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Sample records for single-crystal sapphire optical

  1. Single-Crystal Sapphire Optical Fiber Sensor Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Pickrell, Gary [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States); Scott, Brian [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States); Wang, Anbo [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States); Yu, Zhihao [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States)

    2013-12-31

    This report summarizes technical progress on the program “Single-Crystal Sapphire Optical Fiber Sensor Instrumentation,” funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. This project was completed in three phases, each with a separate focus. Phase I of the program, from October 1999 to April 2002, was devoted to development of sensing schema for use in high temperature, harsh environments. Different sensing designs were proposed and tested in the laboratory. Phase II of the program, from April 2002 to April 2009, focused on bringing the sensor technologies, which had already been successfully demonstrated in the laboratory, to a level where the sensors could be deployed in harsh industrial environments and eventually become commercially viable through a series of field tests. Also, a new sensing scheme was developed and tested with numerous advantages over all previous ones in Phase II. Phase III of the program, September 2009 to December 2013, focused on development of the new sensing scheme for field testing in conjunction with materials engineering of the improved sensor packaging lifetimes. In Phase I, three different sensing principles were studied: sapphire air-gap extrinsic Fabry-Perot sensors; intensity-based polarimetric sensors; and broadband polarimetric sensors. Black body radiation tests and corrosion tests were also performed in this phase. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. At the beginning of Phase II, in June 2004, the BPDI sensor was tested at the Wabash River coal gasifier

  2. Neutron transmission of single-crystal sapphire filters

    International Nuclear Information System (INIS)

    Adib, M.; Kilany, M.; Habib, N.; Fathallah, M.

    2005-01-01

    An additive formula is given that permits the calculation of the nuclear capture, thermal diffuse and Bragg scattering cross-sections as a function of sapphire temperature and crystal parameters. We have developed a computer program that allows calculations of the thermal neutron transmission for the sapphire rhombohedral structure and its equivalent trigonal structure. The calculated total cross-section values and effective attenuation coefficient for single-crystalline sapphire at different temperatures are compared with measured values. Overall agreement is indicated between the formula fits and experimental data. We discuss the use of sapphire single crystal as a thermal neutron filter in terms of the optimum crystal thickness, mosaic spread, temperature, cutting plane and tuning for efficient transmission of thermal-reactor neutrons. (author)

  3. Neutron Transmission of Single-crystal Sapphire Filters

    Science.gov (United States)

    Adib, M.; Kilany, M.; Habib, N.; Fathallah, M.

    2005-05-01

    An additive formula is given that permits the calculation of the nuclear capture, thermal diffuse and Bragg scattering cross-sections as a function of sapphire temperature and crystal parameters. We have developed a computer program that allows calculations of the thermal neutron transmission for the sapphire rhombohedral structure and its equivalent trigonal structure. The calculated total cross-section values and effective attenuation coefficient for single-crystalline sapphire at different temperatures are compared with measured values. Overall agreement is indicated between the formula and experimental data. We discuss the use of sapphire single crystal as a thermal neutron filter in terms of the optimum cystal thickness, mosaic spread, temperature, cutting plane and tuning for efficient transmission of thermal-reactor neutrons.

  4. Neutron transmission of single-crystal sapphire filters

    International Nuclear Information System (INIS)

    Adib, M.; Kilany, M.; Habib, N.; Fathallah, M.

    2004-01-01

    A simple additive formula is given that permits the calculation of the nuclear capture, thermal diffuse and Bragg scattering cross-sections as a function of sapphire temperature and crystal parameters. We have developed a computer program that allows calculations of the thermal neutron transmission for the sapphire rhombohedral structure and its equivalent trigonal structure. The calculated total cross-section values and effective attenuation coefficient for mono-crystalline sapphire at different temperatures are compared with measured values. Overall agreement is indicated between the formula fits and experimental data. We discuss the use of sapphire single-crystal as a thermal neutron filter in terms of the optimum crystal thickness, mosaic spread, temperature, cutting plane and tuning for efficient transmission of thermal-reactor neutrons

  5. On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2005-11-01

    This report summarizes technical progress April-September 2005 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Due to the difficulties described on the last report, field testing of the BPDI system has not continued to date. However, we have developed an alternative high temperature sensing solution, which is described in this report. The sensing system will be installed and tested at TECO's Polk Power Station. Following a site visit in June 2005, our efforts have been focused on preparing for that field test, including he design of the sensor mechanical packaging, sensor electronics, the data transfer module, and the necessary software codes to accommodate this application.. We are currently ready to start sensor fabrication.

  6. Review and perspective: Sapphire optical fiber cladding development for harsh environment sensing

    Science.gov (United States)

    Chen, Hui; Buric, Michael; Ohodnicki, Paul R.; Nakano, Jinichiro; Liu, Bo; Chorpening, Benjamin T.

    2018-03-01

    The potential to use single-crystal sapphire optical fiber as an alternative to silica optical fibers for sensing in high-temperature, high-pressure, and chemically aggressive harsh environments has been recognized for several decades. A key technological barrier to the widespread deployment of harsh environment sensors constructed with sapphire optical fibers has been the lack of an optical cladding that is durable under these conditions. However, researchers have not yet succeeded in incorporating a high-temperature cladding process into the typical fabrication process for single-crystal sapphire fibers, which generally involves seed-initiated fiber growth from the molten oxide state. While a number of advances in fabrication of a cladding after fiber-growth have been made over the last four decades, none have successfully transitioned to a commercial manufacturing process. This paper reviews the various strategies and techniques for fabricating an optically clad sapphire fiber which have been proposed and explored in published research. The limitations of current approaches and future prospects for sapphire fiber cladding are discussed, including fabrication methods and materials. The aim is to provide an understanding of the past research into optical cladding of sapphire fibers and to assess possible material systems for future research on this challenging problem for harsh environment sensors.

  7. Facet Appearance on the Lateral Face of Sapphire Single-Crystal Fibers during LHPG Growth

    Directory of Open Access Journals (Sweden)

    Liudmila D. Iskhakova

    2016-08-01

    Full Text Available Results of the study of the lateral surface of single-crystal (SC sapphire fibers grown along crystallographic directions [ 0001 ] and [ 11 2 ¯ 0 ] by the LHPG method are presented. The appearance or absence of faceting of the lateral surface of the fibers depending on the growth direction is analyzed. The crystallographic orientation of the facets is investigated. The microstructure of the samples is investigated with the help of an optical microscope and a JSM-5910LV scanning electronic microscope (JEOL. The crystallographic orientations of the facets on the SC sapphire fiber surface are determined by electron backscatter diffraction (EBSD. The seed orientation is studied by means of XRD techniques.

  8. Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors

    Directory of Open Access Journals (Sweden)

    Keisuke Iwano

    2016-10-01

    Full Text Available We investigate the optical transmittances of ion-irradiated sapphire crystals as potential vacuum ultraviolet (VUV to near-infrared (NIR window materials of fusion reactors. Under potential conditions in fusion reactors, sapphire crystals are irradiated with hydrogen (H, deuterium (D, and helium (He ions with 1-keV energy and ∼ 1020-m-2 s-1 flux. Ion irradiation decreases the transmittances from 140 to 260 nm but hardly affects the transmittances from 300 to 1500 nm. H-ion and D-ion irradiation causes optical absorptions near 210 and 260 nm associated with an F-center and an F+-center, respectively. These F-type centers are classified as Schottky defects that can be removed through annealing above 1000 K. In contrast, He-ion irradiation does not cause optical absorptions above 200 nm because He-ions cannot be incorporated in the crystal lattice due to the large ionic radius of He-ions. Moreover, the significant decrease in transmittance of the ion-irradiated sapphire crystals from 140 to 180 nm is related to the light scattering on the crystal surface. Similar to diamond polishing, ion irradiation modifies the crystal surface thereby affecting the optical properties especially at shorter wavelengths. Although the transmittances in the VUV wavelengths decrease after ion irradiation, the transmittances can be improved through annealing above 1000 K. With an optical transmittance in the VUV region that can recover through simple annealing and with a high transparency from the ultraviolet (UV to the NIR region, sapphire crystals can therefore be used as good optical windows inside modern fusion power reactors in terms of light particle loadings of hydrogen isotopes and helium.

  9. Thermal neutron scattering kernels for sapphire and silicon single crystals

    International Nuclear Information System (INIS)

    Cantargi, F.; Granada, J.R.; Mayer, R.E.

    2015-01-01

    Highlights: • Thermal cross section libraries for sapphire and silicon single crystals were generated. • Debye model was used to represent the vibrational frequency spectra to feed the NJOY code. • Sapphire total cross section was measured at Centro Atómico Bariloche. • Cross section libraries were validated with experimental data available. - Abstract: Sapphire and silicon are materials usually employed as filters in facilities with thermal neutron beams. Due to the lack of the corresponding thermal cross section libraries for those materials, necessary in calculations performed in order to optimize beams for specific applications, here we present the generation of new thermal neutron scattering kernels for those materials. The Debye model was used in both cases to represent the vibrational frequency spectra required to feed the NJOY nuclear data processing system in order to produce the corresponding libraries in ENDF and ACE format. These libraries were validated with available experimental data, some from the literature and others obtained at the pulsed neutron source at Centro Atómico Bariloche

  10. The density and compositional analysis of titanium doped sapphire single crystal grown by the Czocharlski method

    Science.gov (United States)

    Kusuma, H. H.; Ibrahim, Z.; Othaman, Z.

    2018-03-01

    Titanium doped sapphire (Ti:Al2O3) crystal has attracted attention not only as beautiful gemstones, but also due to their applications as high power laser action. It is very important crystal for tunable solid state laser. Ti:Al2O3 crystals have been success grown using the Czocharlski method with automatic diameter control (ADC) system. The crystals were grown with different pull rates. The structure of the crystal was characterized with X-Ray Diffraction (XRD). The density of the crystal was measurement based on the Archimedes principle and the chemical composition of the crystal was confirmed by the Energy Dispersive X-ray (EDX) Spectroscopy. The XRD patterns of crystals are showed single main peak with a high intensity. Its shows that the samples are single crystal. The Ti:Al2O3 grown with different pull rate will affect the distribution of the concentration of dopant Ti3+ and densities on the sapphire crystals boules as well on the crystal growth process. The increment of the pull rate will increase the percentage distribution of Ti3+ and on the densities of the Ti:Al2O3 crystal boules. This may be attributed to the speed factor of the pull rate of the crystal that then caused changes in the heat flow in the furnace and then causes the homogeneities is changed of species distribution of atoms along crystal.

  11. Characterization of single crystal uranium-oxide thin films grown via reactive-gas magnetron sputtering on yttria-stabilized zirconia and sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Strehle, Melissa M.; Heuser, Brent J., E-mail: bheuser@illinois.edu; Elbakhshwan, Mohamed S.; Han Xiaochun; Gennardo, David J.; Pappas, Harrison K.; Ju, Hyunsu

    2012-06-30

    The microstructure and valence states of three single crystal thin film systems, UO{sub 2} on (11{sup Macron }02) r-plane sapphire, UO{sub 2} on (001) yttria-stabilized zirconia, and U{sub 3}O{sub 8} on (11{sup Macron }02) r-plane sapphire, grown via reactive-gas magnetron sputtering are analyzed primarily with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). XRD analysis indicates the growth of single crystal domains with varying degrees of mosaicity. XPS and UPS analyses yield U-4f, U-5f, O-1s, and O-2p electron binding energies consistent with reported bulk values. A change from p-type to n-type semiconductor behavior induced by preferential sputtering of oxygen during depth profile analysis was observed with both XPS and UPS. Trivalent cation impurities (Nd and Al) in UO{sub 2} lower the Fermi level, shifting the XPS spectral weight. This observation is consistent with hole-doping of a Mott-Hubbard insulator. The uranium oxide-(11{sup Macron }02) sapphire system is unstable with respect to Al interdiffusion across the film-substrate interface at elevated temperature. - Highlights: Black-Right-Pointing-Pointer Single crystal uranium-oxides grown on sapphire and yttria-stabilized zirconia. Black-Right-Pointing-Pointer Anion and cation valence states studied by photoelectron emission spectroscopy. Black-Right-Pointing-Pointer Trivalent Nd and Al impurities lower the Fermi level. Black-Right-Pointing-Pointer Uranium-oxide films on sapphire found to be unstable with respect to Al interdiffusion.

  12. Neurosurgery contact handheld probe based on sapphire shaped crystal

    Science.gov (United States)

    Shikunova, I. A.; Stryukov, D. O.; Rossolenko, S. N.; Kiselev, A. M.; Kurlov, V. N.

    2017-01-01

    A handheld contact probe based on sapphire shaped crystal is developed for intraoperative spectrally-resolved optical diagnostics, laser coagulation and aspiration of malignant brain tissue. The technology was integrated into the neurosurgical workflow for intraoperative real-time identification and removing of invasive brain cancer.

  13. Light refraction in sapphire plates with a variable angle of crystal optical axis to the surface

    International Nuclear Information System (INIS)

    Vetrov, V. N.; Ignatenkov, B. A.

    2013-01-01

    The modification of sapphire by inhomogeneous plastic deformation makes it possible to obtain plates with a variable angle of inclination of the crystal optical axis to the plate surface. The refraction of light in this plate at perpendicular and oblique incidence of a parallel beam of rays is considered. The algorithm of calculating the refractive index of extraordinary ray and the birefringence is proposed.

  14. High performance sapphire windows

    Science.gov (United States)

    Bates, Stephen C.; Liou, Larry

    1993-02-01

    High-quality, wide-aperture optical access is usually required for the advanced laser diagnostics that can now make a wide variety of non-intrusive measurements of combustion processes. Specially processed and mounted sapphire windows are proposed to provide this optical access to extreme environment. Through surface treatments and proper thermal stress design, single crystal sapphire can be a mechanically equivalent replacement for high strength steel. A prototype sapphire window and mounting system have been developed in a successful NASA SBIR Phase 1 project. A large and reliable increase in sapphire design strength (as much as 10x) has been achieved, and the initial specifications necessary for these gains have been defined. Failure testing of small windows has conclusively demonstrated the increased sapphire strength, indicating that a nearly flawless surface polish is the primary cause of strengthening, while an unusual mounting arrangement also significantly contributes to a larger effective strength. Phase 2 work will complete specification and demonstration of these windows, and will fabricate a set for use at NASA. The enhanced capabilities of these high performance sapphire windows will lead to many diagnostic capabilities not previously possible, as well as new applications for sapphire.

  15. Response of Seven Crystallographic Orientations of Sapphire Crystals to Shock Stresses of 16 to 86 GPa

    OpenAIRE

    Kanel, G. I.; Nellis, W. J.; Savinykh, A. S.; Razorenov, S. V.; Rajendran, A. M.

    2009-01-01

    Shock-wave profiles of sapphire (single-crystal Al2O3) with seven crystallographic orientations were measured with time-resolved VISAR interferometry at shock stresses in the range 16 to 86 GPa. Shock propagation was normal to the surface of each cut. The angle between the c-axis of the hexagonal crystal structure and the direction of shock propagation varied from 0 for c-cut up to 90 degrees for m-cut in the basal plane. Based on published shock-induced transparencies, shock-induced optical ...

  16. Third order nonlinear optical properties of a paratellurite single crystal

    Science.gov (United States)

    Duclère, J.-R.; Hayakawa, T.; Roginskii, E. M.; Smirnov, M. B.; Mirgorodsky, A.; Couderc, V.; Masson, O.; Colas, M.; Noguera, O.; Rodriguez, V.; Thomas, P.

    2018-05-01

    The (a,b) plane angular dependence of the third-order nonlinear optical susceptibility, χ(3) , of a c-cut paratellurite (α-TeO2) single crystal was quantitatively evaluated here by the Z-scan technique, using a Ti:sapphire femtosecond laser operated at 800 nm. In particular, the mean value Re( ⟨χ(3)⟩a,b )(α-TeO2) of the optical tensor has been extracted from such experiments via a direct comparison with the data collected for a fused silica reference glass plate. A R e (⟨χ(3)⟩(a,b )(α-TeO2)):R e (χ(3))(SiO2 glass) ratio roughly equal to 49.1 is found, and our result compares thus very favourably with the unique experimental value (a ratio of ˜50) reported by Kim et al. [J. Am. Ceram. Soc. 76, 2486 (1993)] for a pure TeO2 glass. In addition, it is shown that the angular dependence of the phase modulation within the (a,b) plane can be fully understood in the light of the strong dextro-rotatory power known for TeO2 materials. Taking into account the optical activity, some analytical model serving to estimate the diagonal and non-diagonal components of the third order nonlinear susceptibility tensor has been thus developed. Finally, Re( χxxxx(3) ) and Re( χxxyy(3) ) values of 95.1 ×10-22 m 2/V2 and 42.0 ×10-22 m2/V2 , respectively, are then deduced for a paratellurite single crystal, considering fused silica as a reference.

  17. Frequency-doubled diode laser for direct pumping of Ti:sapphire lasers

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2012-01-01

    . However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20...... fs are measured. These results open the opportunity of establishing diode laser pumped Ti:sapphire lasers for e.g. biophotonic applications like retinal optical coherence tomography or pumping of photonic crystal fibers for CARS microscopy.......A single-pass frequency doubled high-power tapered diode laser emitting nearly 1.3 W of green light suitable for direct pumping of Ti:sapphire lasers generating ultrashort pulses is demonstrated. The pump efficiencies reached 75 % of the values achieved with a commercial solid-state pump laser...

  18. LASER PROCESSING ON SINGLE CRYSTALS BY UV PULSE LASER

    OpenAIRE

    龍見, 雅美; 佐々木, 徹; 高山, 恭宜

    2009-01-01

    Laser processing by using UV pulsed laser was carried out on single crystal such as sapphire and diamond in order to understand the fundamental laser processing on single crystal. The absorption edges of diamond and sapphire are longer and shorter than the wave length of UV laser, respectively. The processed regions by laser with near threshold power of processing show quite different state in each crystal.

  19. Neutron Transmission through Sapphire Crystals

    DEFF Research Database (Denmark)

    of simulations, in order to reproduce the transmission of cold neutrons through sapphire crystals. Those simulations were part of the effort of validating and improving the newly developed interface between the Monte-Carlo neutron transport code MCNP and the Monte Carlo ray-tracing code McStas....

  20. Single crystal and optical ceramic multicomponent garnet scintillators: A comparative study

    International Nuclear Information System (INIS)

    Wu, Yuntao; Luo, Zhaohua; Jiang, Haochuan; Meng, Fang; Koschan, Merry; Melcher, Charles L.

    2015-01-01

    Multicomponent garnet materials can be made in optical ceramic as well as single crystal form due to their cubic crystal structure. In this work, high-quality Gd 3 Ga 3 Al 2 O 12 :0.2 at% Ce (GGAG:Ce) single crystal and (Gd,Lu) 3 Ga 3 Al 2 O 12 :1 at% Ce (GLuGAG:Ce) optical ceramics were fabricated by the Czochralski method and a combination of hot isostatic pressing (HIPing) and annealing treatment, respectively. Under optical and X-ray excitation, the GLuGAG:Ce optical ceramic exhibits a broad Ce 3+ transition emission centered at 550 nm, while the emission peak of the GGAG:Ce single crystal is centered at 540 nm. A self-absorption effect in GLuGAG:Ce optical ceramic results in this red-shift of the Ce 3+ emission peak compared to that in the GGAG:Ce single crystal. The light yield under 662 keV γ-ray excitation was 45,000±2500 photons/MeV and 48,200±2410 photons/MeV for the GGAG:Ce single crystal and GLuGAG:Ce optical ceramic, respectively. An energy resolution of 7.1% for 662 keV γ-rays was achieved in the GLuGAG:Ce optical ceramic with a Hamamatsu R6231 PMT, which is superior to the value of 7.6% for a GGAG:Ce single crystal. Scintillation decay time measurements under 137 Cs irradiation show two exponential decay components of 58 ns (47%) and 504 ns (53%) for the GGAG:Ce single crystal, and 84 ns (76%) and 148 ns (24%) for the GLuGAG:Ce optical ceramic. The afterglow level after X-ray cutoff in the GLuGAG:Ce optical ceramic is at least one order of magnitude lower than in the GGAG:Ce single crystal. - Highlights: • GGAG:Ce single crystal and GLuGAG:Ce optical ceramics were fabricated. • The light yield of both ceramic and crystal G(Lu)GAG:Ce reached the level of 45,000 photons/MeV. • GLuGAG:Ce optical ceramic showed a better energy resolution of 7.1% for 662 keV. • GLuGAG:Ce ceramics exhibited lower afterglow level than that of GGAG:Ce single crystals. • The possible optimization strategies for multicomponent aluminate garnets are discussed

  1. Numerical simulation of terahertz-wave propagation in photonic crystal waveguide based on sapphire shaped crystal

    International Nuclear Information System (INIS)

    Zaytsev, Kirill I; Katyba, Gleb M; Mukhina, Elena E; Kudrin, Konstantin G; Karasik, Valeriy E; Yurchenko, Stanislav O; Kurlov, Vladimir N; Shikunova, Irina A; Reshetov, Igor V

    2016-01-01

    Terahertz (THz) waveguiding in sapphire shaped single crystal has been studied using the numerical simulations. The numerical finite-difference analysis has been implemented to characterize the dispersion and loss in the photonic crystalline waveguide containing hollow cylindrical channels, which form the hexagonal lattice. Observed results demonstrate the ability to guide the THz-waves in multi-mode regime in wide frequency range with the minimal power extinction coefficient of 0.02 dB/cm at 1.45 THz. This shows the prospectives of the shaped crystals for highly-efficient THz waveguiding. (paper)

  2. Single Crystal Filters for Neutron Spectrometry

    International Nuclear Information System (INIS)

    Habib, N.

    2008-01-01

    A study of neutron transmission properties trough a large single crystals specimens of Si, Ge, Pb, Bi and sapphire at 300 K and 80 K have been made for a wide range of neutron energies. The effectiveness of such filters is given by the ratio of the total cross-section of unwanted epithermal neutrons to that the desired thermal neutron beam and by the optimum choice of the crystal orientation, its mosaic spread, thickness and temperature.Our study indicates that sapphire is significantly more effective than the others for a wide range of neutron energies

  3. Reduced cost and improved figure of sapphire optical components

    Science.gov (United States)

    Walters, Mark; Bartlett, Kevin; Brophy, Matthew R.; DeGroote Nelson, Jessica; Medicus, Kate

    2015-10-01

    Sapphire presents many challenges to optical manufacturers due to its high hardness and anisotropic properties. Long lead times and high prices are the typical result of such challenges. The cost of even a simple 'grind and shine' process can be prohibitive. The high precision surfaces required by optical sensor applications further exacerbate the challenge of processing sapphire thereby increasing cost further. Optimax has demonstrated a production process for such windows that delivers over 50% time reduction as compared to traditional manufacturing processes for sapphire, while producing windows with less than 1/5 wave rms figure error. Optimax's sapphire production process achieves significant improvement in cost by implementation of a controlled grinding process to present the best possible surface to the polishing equipment. Following the grinding process is a polishing process taking advantage of chemical interactions between slurry and substrate to deliver excellent removal rates and surface finish. Through experiments, the mechanics of the polishing process were also optimized to produce excellent optical figure. In addition to reducing the cost of producing large sapphire sensor windows, the grinding and polishing technology Optimax has developed aids in producing spherical sapphire components to better figure quality. In addition to reducing the cost of producing large sapphire sensor windows, the grinding and polishing technology Optimax has developed aids in producing spherical sapphire components to better figure quality. Through specially developed polishing slurries, the peak-to-valley figure error of spherical sapphire parts is reduced by over 80%.

  4. A peek into the history of sapphire crystal growth

    Science.gov (United States)

    Harris, Daniel C.

    2003-09-01

    After the chemical compositions of sapphire and ruby were unraveled in the middle of the 19th century, chemists set out to grow artificial crystals of these valuable gemstones. In 1885 a dealer in Geneva began to sell ruby that is now believed to have been created by flame fusion. Gemnologists rapidly concluded that the stones were artificial, but the Geneva ruby stimulated A. V. L. Verneuil in Paris to develop a flame fusion process to produce higher quality ruby and sapphire. By 1900 there was brisk demand for ruby manufactured by Verneuil's method, even though Verneuil did not publicly announce his work until 1902 and did not publish details until 1904. The Verneuil process was used with little alteration for the next 50 years. From 1932-1953, S. K. Popov in the Soviet Union established a capability for manufacturing high quality sapphire by the Verneuil process. In the U.S., under government contract, Linde Air Products Co. implemented the Verneuil process for ruby and sapphire when European sources were cut off during World War II. These materials were essential to the war effort for jewel bearings in precision instruments. In the 1960s and 1970s, the Czochralski process was implemented by Linde and its successor, Union Carbide, to make higher crystal quality material for ruby lasers. Stimulated by a government contract for structural fibers in 1966, H. LaBelle invented edge-defined film-fed growth (EFG). The Saphikon company, which is currently owned by Saint-Gobain, evolved from this effort. Independently and simultaneously, Stepanov developed edge-defined film-fed growth in the Soviet Union. In 1967 F. Schmid and D. Viechnicki at the Army Materials Research Lab grew sapphire by the heat exchanger method (HEM). Schmid went on to establish Crystal Systems, Inc. around this technology. Rotem Industries, founded in Israel in 1969, perfected the growth of sapphire hemispheres and near-net-shape domes by gradient solidification. In the U.S., growth of near

  5. Nanostructured sapphire optical fiber for sensing in harsh environments

    Science.gov (United States)

    Chen, Hui; Liu, Kai; Ma, Yiwei; Tian, Fei; Du, Henry

    2017-05-01

    We describe an innovative and scalable strategy of transforming a commercial unclad sapphire optical fiber to an allalumina nanostructured sapphire optical fiber (NSOF) that overcomes decades-long challenges faced in the field of sapphire fiber optics. The strategy entails fiber coating with metal Al followed by subsequent anodization to form anodized alumina oxide (AAO) cladding of highly organized pore channel structure. We show that Ag nanoparticles entrapped in AAO show excellent structural and morphological stability and less susceptibility to oxidation for potential high-temperature surface-enhanced Raman Scattering (SERS). We reveal, with aid of numerical simulations, that the AAO cladding greatly increases the evanescent-field overlap both in power and extent and that lower porosity of AAO results in higher evanescent-field overlap. This work has opened the door to new sapphire fiber-based sensor design and sensor architecture.

  6. Growth and characterization of nonlinear optical single crystals: bis ...

    Indian Academy of Sciences (India)

    Administrator

    molecules have received great attention for NLO applica- tions. However ... Figure 3. Single crystals of bis(cyclohexylammonium) terephthalate (crystal a) and cyclohexylammo- .... from ground state to higher energy states.17 Optical window ...

  7. Use of sapphire as a neutron damage monitor for pressure vessel steels

    International Nuclear Information System (INIS)

    Pells, G.P.; Fudge, A.J.; Murphy, M.J.; Watt, S.

    1989-01-01

    Single crystal α-Al 2 O 3 (sapphire) has been neutron irradiated over a range of dose, dose rate and neutron energy spectra at temperatures from 60 to 310 0 C. Values of optical absorption at 400 nm, the peak of the aluminum vacancy absorption band, were plotted against damage dose expressed in terms of dpa of Al in sapphire obtained from measurements of induced radio-activity in activation foils irradiated with the sapphires and from calculation of the neutron energy spectrum at the irradiation position. The neutron energy spectrum was calculated using modern neutron transport computer codes and adjusted in the light of measurements obtained from multiple foil activation experiments. A simple response curve was obtained for all sapphires irradiated at temperatures between 220 to 310 0 C and for sapphires irradiated below 200 0 C which had been annealed at 290 0 C irrespective of dose rate or neutron beam energy spectrum. The single response curve for irradiations performed in a variety of neutron energy spectra validate the neutron energy spectrum computational procedures

  8. Crystal growth and characterization of new semiorganic nonlinear optical single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kulshrestha, Shobha, E-mail: shobha011986@gmail.com; Shrivastava, A. K., E-mail: ashwaniaks@rediffmail.com [School of Studies in Physics, Jiwaji University Gwalior (M.P.) – 474 011 (India)

    2016-05-06

    An organic material of a L-histidine monohydrochloride single crystal was grown in a distilled water solution using the slow evaporation method at 40–45°C. The grown crystal was transparent and colourless, with a size of about 20 × 9 × 5 mm{sup 3}, obtained within a period of 21 days. The solubility of grown crystals have found out at various temperatures. The UV-visible transmittance studies show that the grown crystals have wide optical transparency in the entire visible region It is observed that the crystal has transparency window from 255nm to 700nm and its energy gap (Eg) found to be is 3.1eV. The grown crystal was subjected to powder X-ray diffraction analysis, confirming that the orthorhombic crystalline nature of the crystal. To identify the surface morphology, the as grown crystal was subjected to FE-SEM technique. The chemical composition of the grown crystal was estimated by Energy dispersive X-ray analysis. The optical behaviour of the grown crystal was analyzed by PL study.

  9. Synthesis, crystal growth, optical, thermal, and mechanical properties of a nonlinear optical single crystal: ammonium sulfate hydrogen sulphamate (ASHS)

    Science.gov (United States)

    Sudhakar, K.; Nandhini, S.; Muniyappan, S.; Arumanayagam, T.; Vivek, P.; Murugakoothan, P.

    2018-04-01

    Ammonium sulfate hydrogen sulphamate (ASHS), an inorganic nonlinear optical crystal, was grown from the aqueous solution by slow evaporation solution growth technique. The single-crystal XRD confirms that the grown single crystal belongs to the orthorhombic system with the space group of Pna21. Powder XRD confirms the crystalline nature and the diffraction planes were indexed. Crystalline perfection of grown crystal was analysed by high-resolution X-ray diffraction rocking curve technique. UV-Vis-NIR studies revealed that ASHS crystal has optical transparency 65% and lower cut-off wavelength at 218 nm. The violet light emission of the crystal was identified by photoluminescence studies. The particle size-dependent second-harmonic generation efficiency for ASHS crystal was evaluated by Kurtz-Perry powder technique using Nd:YAG laser which established the existence of phase matching. Surface laser damage threshold value was evaluated using Nd:YAG laser. Optical homogeneity of the crystal was evaluated using modified channel spectrum method through birefringence study. Thermal analysis reveals that ASHS crystal is stable up to 213 °C. The mechanical behaviour of the ASHS crystal was analysed using Vickers microhardness study.

  10. Synthesis, growth, crystal structure, optical and third order nonlinear optical properties of quinolinium derivative single crystal: PNQI

    Science.gov (United States)

    Karthigha, S.; Krishnamoorthi, C.

    2018-03-01

    An organic quinolinium derivative nonlinear optical (NLO) crystal, 1-ethyl-2-[2-(4-nitro-phenyl)-vinyl]-quinolinium iodide (PNQI) was synthesized and successfully grown by slow evaporation solution growth technique. Formation of a crystalline compound was confirmed by single crystal X-ray diffraction. The quinolinium compound PNQI crystallizes in the triclinic crystal system with a centrosymmetric space group of P-1 symmetry. The molecular structure of PNQI was confirmed by 1H NMR and 13C NMR spectral studies. The thermal properties of the crystal have been investigated by thermogravimetric (TG) and differential scanning calorimetry (DSC) studies. The optical characteristics obtained from UV-Vis-NIR spectral data were described and the cut-off wavelength observed at 506 nm. The etching study was performed to analyse the growth features of PNQI single crystal. The third order NLO properties such as nonlinear refractive index (n2), nonlinear absorption coefficient (β) and nonlinear susceptibility (χ (3)) of the crystal were investigated using Z-scan technique at 632.8 nm of Hesbnd Ne laser.

  11. single crystals

    Indian Academy of Sciences (India)

    2018-05-18

    May 18, 2018 ... Abstract. 4-Nitrobenzoic acid (4-NBA) single crystals were studied for their linear and nonlinear optical ... studies on the proper growth, linear and nonlinear optical ..... between the optic axes and optic sign of the biaxial crystal.

  12. Kerr-lens mode-locked Ti:Sapphire laser pumped by a single laser diode

    Science.gov (United States)

    Kopylov, D. A.; Esaulkov, M. N.; Kuritsyn, I. I.; Mavritskiy, A. O.; Perminov, B. E.; Konyashchenko, A. V.; Murzina, T. V.; Maydykovskiy, A. I.

    2018-04-01

    The performance of a Ti:sapphire laser pumped by a single 461 nm laser diode is presented for both the continuous-wave and the mode-locked regimes of operation. We introduce a simple astigmatism correction scheme for the laser diode beam consisting of two cylindrical lenses affecting the pump beam along the fast axis of the laser diode, which provides the mode-matching between the nearly square-shaped pump beam and the cavity mode. The resulting efficiency of the suggested Ti:Sapphire oscillator pumped by such a laser diode is analyzed for the Ti:sapphire crystals of 3 mm, 5 mm and 10 mm in length. We demonstrate that such a system provides the generation of ultrashort pulses up to 15 fs in duration with the repetition rate of 87 MHz, the average power being 170 mW.

  13. Crystal growth and characterization of a semiorganic nonlinear optical single crystal of gamma glycine

    International Nuclear Information System (INIS)

    Prakash, J. Thomas Joseph; Kumararaman, S.

    2008-01-01

    Gamma glycine has been successfully synthesized by taking glycine and potassium chloride and single crystals have been grown by solvent evaporation method for the first time. The grown single crystals have been analyzed with XRD, Fourier transform infrared (FTIR), and thermo gravimetric and differential thermal analyses (TG/DTA) measurements. Its mechanical behavior has been assessed by Vickers microhardness measurements. Its nonlinear optical property has been tested by Kurtz powder technique. Its optical behavior was examined by UV-vis., and found that the crystal is transparent in the region between 240 and 1200 nm. Hence, it may be very much useful for the second harmonic generation (SHG) applications

  14. Crystal Structure and Ferroelectric Properties of ε-Ga2O3 Films Grown on (0001)-Sapphire.

    Science.gov (United States)

    Mezzadri, Francesco; Calestani, Gianluca; Boschi, Francesco; Delmonte, Davide; Bosi, Matteo; Fornari, Roberto

    2016-11-21

    The crystal structure and ferroelectric properties of ε-Ga 2 O 3 deposited by low-temperature MOCVD on (0001)-sapphire were investigated by single-crystal X-ray diffraction and the dynamic hysteresis measurement technique. A thorough investigation of this relatively unknown polymorph of Ga 2 O 3 showed that it is composed of layers of both octahedrally and tetrahedrally coordinated Ga 3+ sites, which appear to be occupied with a 66% probability. The refinement of the crystal structure in the noncentrosymmetric space group P6 3 mc pointed out the presence of uncompensated electrical dipoles suggesting ferroelectric properties, which were finally demonstrated by independent measurements of the ferroelectric hysteresis. A clear epitaxial relation is observed with respect to the c-oriented sapphire substrate, with the Ga 2 O 3 [10-10] direction being parallel to the Al 2 O 3 direction [11-20], yielding a lattice mismatch of about 4.1%.

  15. Optical properties of Sulfur doped InP single crystals

    Science.gov (United States)

    El-Nahass, M. M.; Youssef, S. B.; Ali, H. A. M.

    2014-05-01

    Optical properties of InP:S single crystals were investigated using spectrophotometric measurements in the spectral range of 200-2500 nm. The absorption coefficient and refractive index were calculated. It was found that InP:S crystals exhibit allowed and forbidden direct transitions with energy gaps of 1.578 and 1.528 eV, respectively. Analysis of the refractive index in the normal dispersion region was discussed in terms of the single oscillator model. Some optical dispersion parameters namely: the dispersion energy (Ed), single oscillator energy (Eo), high frequency dielectric constant (ɛ∞), and lattice dielectric constant (ɛL) were determined. The volume and the surface energy loss functions (VELF & SELF) were estimated. Also, the real and imaginary parts of the complex conductivity were calculated.

  16. Luminescence and scintillation properties of YAG:Ce single crystal and optical ceramics

    CERN Document Server

    Mihóková, E; Mareš, J A; Beitlerová, A; Vedda, A; Nejezchleb, K; Blažek, K; D’Ambrosio, C

    2007-01-01

    We use various techniques to study optical and scintillation properties of Ce-doped yttrium aluminum garnet, Y3Al5O12 (YAG:Ce), in the form of a high-quality industrial single crystal. This was compared to optical ceramics prepared from YAG:Ce nanopowders. We present experimental data in the areas of optical absorption, radioluminescence, scintillation decay, photoelectron yield, thermally stimulated luminescence and radiation-induced absorption. The results point to an interesting feature—the absence of antisite (YAl, i.e. Y at the Al site) defects in optical ceramics. The scintillation decay of the ceramics is faster than that of the single crystal, but its photoelectron yield (measured with 1 μs integration time) is about 30–40% lower. Apart from the photoelectron yield value the YAG:Ce optical ceramic is fully comparable to a high quality industrial YAG:Ce single crystal and can become a competitive scintillator material.

  17. Preparation of a Non-Polar ZnO Film on a Single-Crystal NdGaO3 Substrate by the RF Sputtering Method

    Science.gov (United States)

    Kashiwaba, Y.; Tanaka, Y.; Sakuma, M.; Abe, T.; Imai, Y.; Kawasaki, K.; Nakagawa, A.; Niikura, I.; Kashiwaba, Y.; Osada, H.

    2018-04-01

    Preparation of non-polar ZnO ( 11\\overline{2} 0 ) films on single-crystal NdGaO3 (NGO) (001) substrates was successfully achieved by the radio frequency (RF) sputtering method. Orientation, deposition rate, and surface roughness of ZnO films strongly depend on the working pressure. Characteristics of ZnO films deposited on single-crystal NGO (001) substrates were compared with those of ZnO films deposited on single-crystal sapphire ( 01\\overline{1} 2 ) substrates. An x-ray diffraction peak of the ZnO ( 11\\overline{2} 0 ) plane was observed on ZnO films deposited on single-crystal NGO (001) substrates under working pressure of less than 0.5 Pa. On the other hand, uniaxially oriented ZnO ( 11\\overline{2} 0 ) films on single-crystal sapphire ( 01\\overline{1} 2 ) substrates were observed under working pressure of 0.1 Pa. The mechanism by which the diffraction angle of the ZnO ( 11\\overline{2} 0 ) plane on single-crystal NGO (001) substrates was shifted is discussed on the basis of anisotropic stress of lattice mismatch. The deposition rate of ZnO films decreased with an increase in working pressure, and the deposition rate on single-crystal NGO (001) substrates was larger than that on single-crystal sapphire ( 01\\overline{1} 2 ) substrates. Root mean square (RMS) roughness of ZnO films increased with an increase in working pressure, and RMS roughness of ZnO films on single-crystal NGO (001) substrates was smaller than that of ZnO films on single-crystal sapphire ( 01\\overline{1} 2 ) substrates even though the film thickness on single-crystal NGO (001) substrates was greater than that on sapphire substrates. It is thought that a single-crystal NGO (001) substrate is useful for deposition of non-polar ZnO ( 11\\overline{2} 0 ) films.

  18. Efficient continuous-wave and passively Q-switched pulse laser operations in a diffusion-bonded sapphire/Er:Yb:YAl3(BO3)4/sapphire composite crystal around 1.55 μm.

    Science.gov (United States)

    Chen, Yujin; Lin, Yanfu; Huang, Jianhua; Gong, Xinghong; Luo, Zundu; Huang, Yidong

    2018-01-08

    A composite crystal consisting of a 1.5-mm-thick Er:Yb:YAl 3 (BO 3 ) 4 crystal between two 1.2-mm-thick sapphire crystals was fabricated by the thermal diffusion bonding technique. Compared with a lone Er:Yb:YAl 3 (BO 3 ) 4 crystal measured under the identical experimental conditions, higher laser performances were demonstrated in the sapphire/Er:Yb:YAl 3 (BO 3 ) 4 /sapphire composite crystal due to the reduction of the thermal effects. End-pumped by a 976 nm laser diode in a hemispherical cavity, a 1.55 μm continuous-wave laser with a maximum output power of 1.75 W and a slope efficiency of 36% was obtained in the composite crystal when the incident pump power was 6.54 W. Passively Q-switched by a Co 2+ :MgAl 2 O 4 crystal, a 1.52 μm pulse laser with energy of 10 μJ and repetition frequency of 105 kHz was also realized in the composite crystal. Pulse width was 315 ns. The results show that the sapphire/Er:Yb:YAl 3 (BO 3 ) 4 /sapphire composite crystal is an excellent active element for 1.55 μm laser.

  19. Growth and characterization of nonlinear optical single crystal: Nicotinic L-tartaric

    Energy Technology Data Exchange (ETDEWEB)

    Sheelarani, V.; Shanthi, J., E-mail: shanthinelson@gmail.com [Department of Physics, Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore-641043 (India)

    2015-06-24

    Nonlinear optical single crystals were grown from Nicotinic and L-Tartaric acid by slow evaporation technique at room temperature. Structure of the grown crystal was confirmed by single crystal X-ray diffraction studies, The crystallinity of the Nicotinic L-Tartaric (NLT) crystals was confirmed from the powder XRD pattern. The transparent range and cut off wavelength of the grown crystal was studied by the UV–Vis spectroscopic analysis.The thermal stability of the crystal was studied by TG-DTA. The second harmonic generation (SHG) efficiency of NLT was confirmed by Kurtz Perry technique.

  20. Generation of continuous-wave single-frequency 1.5 W 378 nm radiation by frequency doubling of a Ti:sapphire laser.

    Science.gov (United States)

    Cha, Yong-Ho; Ko, Kwang-Hoon; Lim, Gwon; Han, Jae-Min; Park, Hyun-Min; Kim, Taek-Soo; Jeong, Do-Young

    2010-03-20

    We have generated continuous-wave single-frequency 1.5 W 378 nm radiation by frequency doubling a high-power Ti:sapphire laser in an external enhancement cavity. An LBO crystal that is Brewster-cut and antireflection coated on both ends is used for a long-term stable frequency doubling. By optimizing the input coupler's reflectivity, we could generate 1.5 W 378 nm radiation from a 5 W 756 nm Ti:sapphire laser. According to our knowledge, this is the highest CW frequency-doubled power of a Ti:sapphire laser.

  1. Formation of Au nanoparticles in sapphire by using Ar ion implantation and thermal annealing

    International Nuclear Information System (INIS)

    Zhou, L.H.; Zhang, C.H.; Yang, Y.T.; Li, B.S.; Zhang, L.Q.; Fu, Y.C.; Zhang, H.H.

    2009-01-01

    In this paper, we present results of the synthesis of gold nanoclusters in sapphire, using Ar ion implantation and annealing in air. Unlike the conventional method of Au implantation followed by thermal annealing, Au was deposited on the surface of m- and a- cut sapphire single crystal samples including those pre-implanted with Ar ions. Au atoms were brought into the substrate by subsequent implantation of Ar ions to form Au nanoparticles. Samples were finally annealed stepwisely in air at temperatures ranging from 400 to 800 deg. C and then studied using UV-vis absorption spectrometry, transmission electron microscopy and Rutherford backscattered spectrometry. Evidence of the formation Au nanoparticles in the sapphire can be obtained from the characteristic surface plasmon resonance (SPR) absorption band in the optical absorption spectra or directly from the transmission electron microscopy. The results of optical absorption spectra indicate that the specimen orientations and pre-implantation also influence the size and the volume fraction of Au nanoparticles formed. Theoretical calculations using Maxwell-Garnett effective medium theory supply a good interpretation of the optical absorption results.

  2. Site location and optical properties of Eu implanted sapphire

    International Nuclear Information System (INIS)

    Marques, C.; Wemans, A.; Maneira, M.J.P.; Kozanecki, A.; Silva, R.C. da; Alves, E.

    2005-01-01

    Synthetic colourless transparent (0 0 0 1) sapphire crystals were implanted at room temperature with 100 keV europium ions to fluences up to 1 x 10 16 cm -2 . Surface damage is observed at low fluences, as seen by Rutherford backscattering spectrometry under channelling conditions. Optical absorption measurements revealed a variety of structures, most probably related to F-type defects characteristic of implantation damage. Thermal treatments in air or in vacuum up to 1000 deg. C do not produce noticeable changes both in the matrix or the europium profiles. However, the complete recovery of the implantation damage and some redistribution of the europium ions is achieved after annealing at 1300 deg. C in air. Detailed lattice site location studies performed for various axial directions allowed to assess the damage recovery and the incorporation of the Eu ions into well defined crystallographic sites, possibly in an oxide phase also inferred from optical absorption measurements

  3. Single-crystal films of a combination of materials (co-crystal) involving DAST and IR-125 for electro-optic applications

    Science.gov (United States)

    Narayanan, A.; Titus, J.; Rajagopalan, H.; Vippa, P.; Thakur, M.

    2006-03-01

    Single-crystal film of DAST (4'-dimethylamino-N-methyl-4-stilbazolium tosylate) has been shown [1] to have exceptionally large electro-optic coefficients (r11 ˜ 770 pm/V at 633 nm). In this report, single crystal film of a combination of materials (co-crystal) involving DAST and a dye molecule IR-125 will be discussed. Modified shear method was used to prepare the co-crystal films. The film has been characterized using polarized optical microscopy, optical absorption spectroscopy and x-ray diffraction. The optical absorption spectrum has two major bands: one at about 350--600 nm corresponding to DAST and the other at about 600-900 nm corresponding to IR-125. The x-ray diffraction results show peaks involving the presence of DAST and IR-125 within the co-crystal film. Since the co-crystal has strong absorption at longer wavelengths it is expected to show higher electro-optic coefficients at longer wavelengths. Preliminary measurements at 1.55 μm indicate a high electro-optic coefficient of the co-crystal film. [1] Swamy, Kutty, Titus, Khatavkar, Thakur, Appl. Phys. Lett. 2004, 85, 4025; Kutty, Thakur, Appl. Phys. Lett. 2005, 87, 191111.

  4. Wrinkle-Free Single-Crystal Graphene Wafer Grown on Strain-Engineered Substrates.

    Science.gov (United States)

    Deng, Bing; Pang, Zhenqian; Chen, Shulin; Li, Xin; Meng, Caixia; Li, Jiayu; Liu, Mengxi; Wu, Juanxia; Qi, Yue; Dang, Wenhui; Yang, Hao; Zhang, Yanfeng; Zhang, Jin; Kang, Ning; Xu, Hongqi; Fu, Qiang; Qiu, Xiaohui; Gao, Peng; Wei, Yujie; Liu, Zhongfan; Peng, Hailin

    2017-12-26

    Wrinkles are ubiquitous for graphene films grown on various substrates by chemical vapor deposition at high temperature due to the strain induced by thermal mismatch between the graphene and substrates, which greatly degrades the extraordinary properties of graphene. Here we show that the wrinkle formation of graphene grown on Cu substrates is strongly dependent on the crystallographic orientations. Wrinkle-free single-crystal graphene was grown on a wafer-scale twin-boundary-free single-crystal Cu(111) thin film fabricated on sapphire substrate through strain engineering. The wrinkle-free feature of graphene originated from the relatively small thermal expansion of the Cu(111) thin film substrate and the relatively strong interfacial coupling between Cu(111) and graphene, based on the strain analyses as well as molecular dynamics simulations. Moreover, we demonstrated the transfer of an ultraflat graphene film onto target substrates from the reusable single-crystal Cu(111)/sapphire growth substrate. The wrinkle-free graphene shows enhanced electrical mobility compared to graphene with wrinkles.

  5. Growth Aspects, Structural and Optical Properties of 2-aminopyridinium 2,4 Dinitrophenolate Single Crystal

    Directory of Open Access Journals (Sweden)

    S. Reena Devi

    2017-06-01

    Full Text Available Organic single crystal of 2-aminopyridinium 2,4-dinitrophenolate single crystal was grown by slow evaporation technique. The cell parameters and space group (P were determined from single X-ray diffraction analysis. HRXRD studies ascertained the crystalline quality. UV-Visible and PL spectral studies revealed the emission in red region, transparency (75% cutoff wavelength around 440 nm respectively. The laser damage threshold of grown crystal was estimated by using Nd:YAG laser beam and these results were mutually related with specific heat capacity of the grown crystal. The third-order nonlinear optical parameters were estimated by Z-scan technique which is useful for optical applications.

  6. Study of structural and optical properties of YAG and Nd:YAG single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kostić, S. [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Lazarević, Z.Ž., E-mail: lzorica@yahoo.com [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Radojević, V. [Faculty of Technology and Metallurgy, University of Belgrade, Belgrade (Serbia); Milutinović, A.; Romčević, M.; Romčević, N.Ž. [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Valčić, A. [Faculty of Technology and Metallurgy, University of Belgrade, Belgrade (Serbia)

    2015-03-15

    Highlights: • Transparent YAG and pale pink Nd:YAG single crystals were produced by the Czochralski technique. • Growth mechanisms and shape of the liquid/solid interface and incorporation of Nd{sup 3+} were studied. • The structure of the crystals was investigated by X-ray diffraction, Raman and IR spectroscopy. • The 15 Raman and 17 IR modes were observed. • The obtained YAG and Nd:YAG single crystals were without core and of good optical quality. - Abstract: Yttrium aluminum garnet (YAG, Y{sub 3}Al{sub 5}O{sub 12}) and yttrium aluminum garnet doped with neodymium (Nd:YAG) single crystals were grown by the Czochralski technique. The critical diameter and the critical rate of rotation were calculated. Suitable polishing and etching solutions were determined. As a result of our experiments, the transparent YAG and pale pink Nd:YAG single crystals were produced. The obtained crystals were studied by X-ray diffraction, Raman and IR spectroscopy. The crystal structure was confirmed by XRD. The 15 Raman and 17 IR modes were observed. The Raman and IR spectroscopy results are in accordance with X-ray diffraction analysis. The obtained YAG and Nd:YAG single crystals were without core and of good optical quality. The absence of a core was confirmed by viewing polished crystal slices. Also, it is important to emphasize that the obtained Nd:YAG single crystal has a concentration of 0.8 wt.% Nd{sup 3+} that is characteristic for laser materials.

  7. Fundamental optical absorption edge in MnGa2Te4 single crystals

    International Nuclear Information System (INIS)

    Medvedkin, G.A.; Rud, Yu.V.; Tairov, M.A.

    1988-01-01

    A study is made of the optical properties of oriented MnGa 2 Te 4 crystals in the region of the fundamental absorption edge. The energy gap width for the temperatures 77, 300, and 370 K is determined to be E G = 1.635, 1.52, and 1.50 eV. The spectral response α(ℎω/2π) is found to follow Urbach's rule thoughout the temperature range studied, the slope of the absorption edge remaining constant (α = 10 2 cm -1 ). Crystal annealing with subsequent rapid cooling results in a shift of the absorption edge longward by 25 meV with the exponential form of α(ℎω/2π) prevailing over the range T = 77 to 370 K. An analysis shows the optical absorption in the region of the fundamental edge to be a sum of the effects coming from the density-of-states tails, local scattering centers associated with a high vacancy concentration, and electron-phonon interaction. Optical linear dichroism of the absorption edge of MnGa 2 Te 4 single crystals with pseudotetragonal structure is revealed and studied. The single crystals are established to be optically uniaxial, their optical transmission dichroism being negative. It is shown that the minimal direct optical transitions in MnGa 2 Te 4 are allowed in the E parallel c polarization in the temperature range 77 to 370 K, the crystal-field splitting of the valence band increasing with temperature. (author)

  8. Self-cavity lasing in optically pumped single crystals of p-sexiphenyl

    International Nuclear Information System (INIS)

    Yanagi, Hisao; Tamura, Kenji; Sasaki, Fumio

    2016-01-01

    Organic single-crystal self-cavities are prepared by solution growth of p-sexiphenyl (p-6P). Based on Fabry-Pérot feedback inside a quasi-lozenge-shaped platelet crystal, edge-emitting laser is obtained under optical pumping. The multimode lasing band appears at the 0-1 or 0-2 vibronic progressions depending on the excitation conditions which affect the self-absorption effect. Cavity-size dependence of amplified spontaneous emission (ASE) is investigated with laser-etched single crystals of p-6P. As the cavity length of square-shaped crystal is reduced from 100 to 10 μm, ASE threshold fluence is decreased probably due to size-dependent light confinement in the crystal cavity.

  9. Self-reporting inhibitors: single crystallization process to get two optically pure enantiomers.

    Science.gov (United States)

    Wan, Xinhua; Ye, Xichong; Cui, Jiaxi; Li, Bowen; Li, Na; Zhang, Jie

    2018-05-22

    Collection of two optically pure enantiomers in a single crystallization process can significantly increase the chiral separation efficiency but it's hard to realize nowadays. Herein we describe, for the first time, a self-reporting strategy for visualizing the crystallization process by a kind of dyed self-assembled inhibitors made from the copolymers with tri(ethylene glycol)-grafting polymethylsiloxane as main chains and poly(N6-methacryloyl-L-lysine) as side chains. When applied with seeds together for the fractional crystallization of conglomerates, the inhibitors can label the formation of the secondary crystals and guide us to completely separate the crystallization process of two enantiomers with colorless crystals as the first product and red crystals as the secondary product. This method leads to high optical purity of D/L-Asn·H2O (99.9 ee% for D-crystals and 99.5 ee% for L-crystals) in a single crystallization process. Moreover, it requires low feeding amount of additives and shows excellent recyclability. We foresee its great potential in developing novel chiral separation methods that can be used in different scales. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Optical power limiting and transmitting properties of cadmium iodide single crystals: Temperature dependence

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. Idrish, E-mail: m.miah@griffith.edu.a [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

    2009-09-14

    Optical limiting properties of the single crystals of cadmium iodide are investigated using ns laser pulses. It is found that the transmissions in the crystals increase with increasing temperature. However, they limit the transmissions at high input powers. The limiting power is found to be higher at higher temperature. From the measured transmission data, the photon absorption coefficients are estimated. The temperature dependence of the coefficients shows a decrease in magnitude with increasing temperature. This might be due to the temperature-dependent bandgap shift of the material. The results demonstrate that the cadmium iodide single crystals are promising materials for applications in optical power limiting devices.

  11. Optical power limiting and transmitting properties of cadmium iodide single crystals: Temperature dependence

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2009-01-01

    Optical limiting properties of the single crystals of cadmium iodide are investigated using ns laser pulses. It is found that the transmissions in the crystals increase with increasing temperature. However, they limit the transmissions at high input powers. The limiting power is found to be higher at higher temperature. From the measured transmission data, the photon absorption coefficients are estimated. The temperature dependence of the coefficients shows a decrease in magnitude with increasing temperature. This might be due to the temperature-dependent bandgap shift of the material. The results demonstrate that the cadmium iodide single crystals are promising materials for applications in optical power limiting devices.

  12. Detection of solar neutrinos with a torsion balance with sapphire crystal

    Science.gov (United States)

    Cruceru, M.; Nicolescu, G.

    2018-01-01

    The solar neutrinos (antineutrinos) are detected with a dedicated torsion balance in the case when they interact coherently on stiff crystals (sapphire with high Debye temperature ∼1000K and lead with ∼100K Debye temperature). The balance consists in two equal masses of lead and sapphire, of 25g. An autocollimator coupled to this balance measures small rotation angles of the balance. The force with which neutrino flux interacts with these crystals is between 10-5 dyn and 10-8 dyn, comparable with that reported in Weber’s experiments [1]. A diurnal effect is observed for solar neutrinos due to the rotation of the Earth around its own axes. The solar neutrino flux obtained at the site of our experiment is ∼3.8*1010neutrinos/cm2*s [2]. Experimental data for neutrinos signals from this high sensitivity torsion balance are presented and commented [3].

  13. Testing of Sapphire Optical Fiber and Sensors in Intense Radiation Fields When Subjected to Very High Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Blue, Thomas [The Ohio State Univ., Columbus, OH (United States); Windl, Wolfgang [The Ohio State Univ., Columbus, OH (United States)

    2017-12-15

    The primary objective of this project was to determine the optical attenuation and signal degradation of sapphire optical fibers & sensors (temperature & strain), in-situ, operating at temperatures up to 1500°C during reactor irradiation through experiments and modeling. The results will determine the feasibility of extending sapphire optical fiber-based instrumentation to extremely high temperature radiation environments. This research will pave the way for future testing of sapphire optical fibers and fiber-based sensors under conditions expected in advanced high temperature reactors.

  14. Growth, optical, ICP and thermal studies of nonlinear optical single crystal: Sodium acid phthalate (NaAP)

    Science.gov (United States)

    Mahadevan, M.; Arivanandhan, M.; Elangovan, K.; Anandan, P.; Ramachandran, K.

    2017-07-01

    Good quality single crystals of sodium acid phthalate (NaAP) were grown by slow evaporation technique. Single crystal X-ray diffraction study of the grown crystal reveals that the crystal belongs to orthorhombic system with space group B2ab. Fourier transform infrared spectrum confirms the presence of the functional groups of the grown material. Inductively coupled plasma emission spectroscopy analysis is used to confirm the presence of Na element in the sample. Thermal analysis of the NaAP crystal shows that the crystal is stable up to 140°C. Optical transmittance of the grown crystal was recorded in the wavelength range from 200 and 800 nm using UV-Vis-NIR spectrophotometer. The second harmonic generation of NaAP was analysed using Kurtz powder technique.

  15. Cross-section of single-crystal materials used as thermal neutron filters

    International Nuclear Information System (INIS)

    Adib, M.

    2005-01-01

    Transmission properties of several single crystal materials important for neutron scattering instrumentation are presented. A computer codes are developed which permit the calculation of thermal diffuse and Bragg-scattering cross-sections of silicon., and sapphire as a function of material's constants, temperature and neutron energy, E, in the range 0.1 MeV .A discussion of the use of their single-crystal as a thermal neutron filter in terms of the optimum crystal thickness, mosaic spread, temperature, cutting plane and tuning for efficient transmission of thermal-reactor neutrons is given

  16. Synthesis, crystal structure, growth, optical and third order nonlinear optical studies of 8HQ2C5N single crystal - An efficient third-order nonlinear optical material

    Energy Technology Data Exchange (ETDEWEB)

    Divya Bharathi, M.; Ahila, G.; Mohana, J. [Department of Physics, Presidency College, Chennai 600005 (India); Chakkaravarthi, G. [Department of Physics, CPCL Polytechnic College, Chennai 600068 (India); Anbalagan, G., E-mail: anbu24663@yahoo.co.in [Department of Nuclear Physics, University of Madras, Chennai 600025 (India)

    2017-05-01

    A neoteric organic third order nonlinear optical material 8-hydroxyquinolinium 2-chloro-5-nitrobenzoate dihydrate (8HQ2C5N) was grown by slow cooling technique using ethanol: water (1:1) mixed solvent. The calculated low value of average etch pit solidity (4.12 × 10{sup 3} cm{sup −2}) indicated that the title crystal contain less defects. From the single crystal X-ray diffraction data, it was endowed that 8HQ2C5N crystal belongs to the monoclinic system with centrosymmetric space group P2{sub 1}/c and the cell parameters values, a = 9.6546 (4) Ǻ, b = 7.1637(3) Ǻ, c = 24.3606 (12) Ǻ, α = γ = 90°, β = 92.458(2)° and volume = 1683.29(13) Ǻ{sup 3}. The FT-IR and FT-Raman spectrum were used to affirm the functional group of the title compound. The chemical structure of 8HQ2C5N was scrutinized by {sup 13}C and {sup 1}H NMR spectral analysis and thermal stability through the differential scanning calorimetry study. Using optical studies the lower cut-off wavelength and optical band gap of 8HQ2C5N were found to be 364 nm and 3.17 eV respectively. Using the single oscillator model suggested by Wemple – Didomenico, the oscillator energy (E{sub o}), the dispersion energy (E{sub d}) and static dielectric constant (ε{sub o}) were estimated. The third-order susceptibility were determined as Im χ{sup (3)} = 2.51 × 10{sup −5} esu and Re χ{sup (3)} = 4.46 × 10{sup −7} esu. The theoretical third-order nonlinear optical susceptibility χ{sup (3)} was calculated and the results were compared with experimental value. Photoluminescence spectrum of 8HQ2C5N crystal showed the yellow emission. The crystal had the single shot laser damage threshold of 5.562 GW/cm{sup 2}. Microhardness measurement showed that 8HQ2C5N belongs to a soft material category. - Highlights: • A new organic single crystals were grown and the crystal structure was reported. • Crystal possess, good transmittance, thermal and mechanical stability. • Single shot LDT value is found to be

  17. Optical and structural behaviour of Mn implanted sapphire

    International Nuclear Information System (INIS)

    Marques, C.; Franco, N.; Kozanecki, A.; Silva, R.C. da; Alves, E.

    2006-01-01

    Sapphire single crystals were implanted at room temperature with 180 keV manganese ions to fluences up to 1.8 x 10 17 cm -2 . The samples were annealed at 1000 deg. C in oxidizing or reducing atmosphere. Surface damage was observed after implantation of low fluences, the amorphous phase being observed after implantation of 5 x 10 16 cm -2 , as seen by Rutherford backscattering spectroscopy under channelling conditions. Thermal treatments in air annealed most of the implantation related defects and promoted the redistribution of the manganese ions, in a mixed oxide phase. X-ray diffraction studies revealed the presence of MnAl 2 O 4 . On the contrary, similar heat treatments in vacuum led to enhanced out diffusion of Mn while the matrix remained highly damaged. The analysis of laser induced luminescence performed after implantation showed the presence of an intense red emission

  18. Infrared-active optical phonons in LiFePO4 single crystals

    Science.gov (United States)

    Stanislavchuk, T. N.; Middlemiss, D. S.; Syzdek, J. S.; Janssen, Y.; Basistyy, R.; Sirenko, A. A.; Khalifah, P. G.; Grey, C. P.; Kostecki, R.

    2017-07-01

    Infrared-active optical phonons were studied in olivine LiFePO4 oriented single crystals by means of both rotating analyzer and rotating compensator spectroscopic ellipsometry in the spectral range between 50 and 1400 cm-1. The eigenfrequencies, oscillator strengths, and broadenings of the phonon modes were determined from fits of the anisotropic harmonic oscillator model to the data. Optical phonons in a heterosite FePO4 crystal were measured from the delithiated ab-surface of the LiFePO4 crystal and compared with the phonon modes of the latter. Good agreement was found between experimental data and the results of solid-state hybrid density functional theory calculations for the phonon modes in both LiFePO4 and FePO4.

  19. Crystal growth and optical properties of Sm:CaNb2O6 single crystal

    International Nuclear Information System (INIS)

    Di Juqing; Xu Xiaodong; Xia Changtai; Zeng Huidan; Cheng Yan; Li Dongzhen; Zhou Dahua; Wu Feng; Cheng Jimeng; Xu Jun

    2012-01-01

    Highlights: ► Sm:CaNb 2 O 6 single crystal was grown by the Czochralski method. ► Thermal expansion coefficients and J–O parameters were calculated. ► We found that this crystal had high quantum efficiency of 97%. - Abstract: Sm:CaNb 2 O 6 single crystal has been grown by the Czochralski method. Its high-temperature X-ray powder diffraction, optical absorption, emission spectroscopic as well as lifetime have been studied. Thermal expansion coefficients (α), J–O parameters (Ω i ), radiative lifetime (τ rad ), branching ratios (β) and stimulated emission cross-sections (σ e ) were calculated. The quantum efficiency (η) was calculated to be 97%. The intense peak emission cross section at 610, 658 nm were calculated to be 2.40 × 10 −21 , 2.42 × 10 −21 cm 2 . These results indicate that Sm:CaNb 2 O 6 crystal has potential use in visible laser and photonic devices area.

  20. Effect of Metal Dopant on Ninhydrin—Organic Nonlinear Optical Single Crystals

    Directory of Open Access Journals (Sweden)

    R. S. Sreenivasan

    2013-01-01

    Full Text Available In the present work, metal (Cu2+-substituted ninhydrin single crystals were grown by slow evaporation method. The grown crystals have been subjected to single crystal XRD, powder X-ray diffraction, FTIR, dielectric and SHG studies. Single crystal X-ray diffraction analysis reveals that the compound crystallizes in monoclinic system with noncentrosymmetric space group P21 with lattice parameters a=11.28 Å, b=5.98 Å, c=5.71 Å, α=90∘, β=98.57, γ=90∘, and V=381 (Å3, which agrees very well with the reported value. The sharp and strong peaks in the powder X-ray diffraction pattern confirm the good crystallinity of the grown crystals. The presence of dopants marginally altered the lattice parameters without affecting the basic structure of the crystal. The UV-Vis transmittance spectrum shows that the crystal has a good optical transmittance in the entire visible region with lower cutoff wavelength 314 nm. The vibrational frequencies of various functional groups in the crystals have been derived from FT-IR analysis. Based on the shifts in the vibrations, the presence of copper in the lattice of the grown crystal is clearly established from the pure ninhydrin crystals. Both dielectric constant and dielectric loss decrease with the increase in frequency. The second harmonic generation efficiency was measured by employing powder Kurtz method.

  1. Origin for the shape of Au small crystals formed inside sapphire by ion implantation

    International Nuclear Information System (INIS)

    Ohkubo, M.; Hioki, T.

    1989-01-01

    In ion-implanted oxides, precipitation is usually formed except the case of forming solid solution. The precipitation comprises the metallic particles of implanted atoms, the oxide of implanted atoms, the metal of matrix elements, the compound of implanted atoms and matrix and so on. In particular, the metallic particles of implanted atoms are frequently faceted. From the facets, the equilibrium shape of crystals can be imagined. The equilibrium shape is determined so that the surface free energy is to be minimized. However, the shape of the metallic particles precipitated inside oxides should not be such equilibrium shape because they come in contact with foreign crystals. As the result, in the precipitation phenomena induced by ion implantation, the crystal structures of precipitated particles and substrates, the crystallographic relation between two crystals, interfacial energy and so on must be taken in consideration. In this paper, the report is made on the shape of the metallic gold particles formed inside sapphires by ion implantation that it was caused by only the crystal habit of sapphires regardless of the above-mentioned complexity. (K.I.)

  2. Intensity Noise Transfer Through a Diode-pumped Titanium Sapphire Laser System

    DEFF Research Database (Denmark)

    Tawfieq, Mahmoud; Hansen, Anders Kragh; Jensen, Ole Bjarlin

    2017-01-01

    higher RIN than a setup with only a single nonlinear crystal. The Ti:S is shown to have a cut-off frequency around 500 kHz, which means that noise structures of the pump laser above this frequency are strongly suppressed. Finally, the majority of the Ti:S noise seems to originate from the laser itself......In this paper, we investigate the noise performance and transfer in a titanium sapphire (Ti:S) laser system. This system consists of a DBR tapered diode laser, which is frequency doubled in two cascaded nonlinear crystals and used to pump the Ti:S laser oscillator. This investigation includes...... electrical noise characterizations of the utilized power supplies, the optical noise of the fundamental light, the second harmonic light, and finally the optical noise of the femtosecond pulses emitted by the Ti:S laser. Noise features originating from the electric power supply are evident throughout...

  3. Thermal stress resistance of ion implanted sapphire crystals

    International Nuclear Information System (INIS)

    Gurarie, V.N.; Jamieson, D.N.; Szymanski, R.; Orlov, A.V.; Williams, J.S.; Conway, M.

    1999-01-01

    Monocrystals of sapphire have been subjected to ion implantation with 86 keV Si - and 80 keV Cr - ions to doses in the range of 5x10 14 -5x10 16 cm -2 prior to thermal stress testing in a pulsed plasma. Above a certain critical dose ion implantation is shown to modify the near-surface structure of samples by introducing damage, which makes crack nucleation easier under the applied stress. The effect of ion dose on the stress resistance is investigated and the critical doses which produce a noticeable change in the stress resistance are determined. The critical dose for Si ions is shown to be much lower than that for Cr - ions. However, for doses exceeding 2x10 16 cm -2 the stress resistance parameter decreases to approximately the same value for both implants. The size of the implantation-induced crack nucleating centers and the density of the implantation-induced defects are considered to be the major factors determining the stress resistance of sapphire crystals irradiated with Si - and Cr - ions

  4. Structural and optical properties of WTe2 single crystals synthesized by DVT technique

    Science.gov (United States)

    Dixit, Vijay; Vyas, Chirag; Pathak, V. M.; Soalanki, G. K.; Patel, K. D.

    2018-05-01

    Layered transition metal di-chalcogenide (LTMDCs) crystals have attracted much attention due to their potential in optoelectronic device applications recently due to realization of their monolayer based structures. In the present investigation we report growth of WTe2 single crystals by direct vapor transport (DVT) technique. These crystals are then characterized by energy dispersive analysis of x-rays (EDAX) to study stoichiometric composition after growth. The structural properties are studied by x-ray diffraction (XRD) and selected area electron diffraction (SAED) is used to confirm orthorhombic structure of grown WTe2 crystal. Surface morphological properties of the crystals are also studied by scanning electron microscope (SEM). The optical properties of the grown crystals are studied by UV-Visible spectroscopy which gives direct band gap of 1.44 eV for grown WTe2 single crystals.

  5. Analyses of significant features of L-Prolinium Picrate single crystal: An excellent material for non linear optical applications

    Energy Technology Data Exchange (ETDEWEB)

    Thukral, Kanika [Academy of Scientific and Innovative Research, CSIR- National Physical Laboratory, New Delhi, 110012 (India); CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi, 110 012 (India); Vijayan, N., E-mail: nvijayan@nplindia.org [CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi, 110 012 (India); Vij, Mahak [CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi, 110 012 (India); Nagaraja, C.M. [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, 140001, Punjab (India); Jayaramakrishnan, V. [Centro De Investigations En Optica, Loma del Bosque 115, Colonia Lomas del Campestre, León, Guanajuato, Código Postal, 37150 (Mexico); Jayalakshmy, M.S. [International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam, Kerala, 686560 (India); Kant, Rajni [Department of Physics and Electronics, University of Jammu, Jammu Tawi, 180006 (India)

    2017-06-15

    Today the fundamental aspect of the researchers is to explore maximum physical properties of the material for device fabrication. In the present article, single crystal X-ray diffraction has been carried out to verify the formation of the synthesized compound. In addition to that, powder X-ray diffraction has been performed to obtain diffraction pattern of L-Prolinium Picrate single crystal. The strain present inside the single crystal was measured using Hall-Williamson equation from PXRD measurements. The dark current and photon current was obtained from photoconductivity technique whose plot depicted that the sample was negative photoconducting material. Optical homogeneity of the single crystal was analyzed using birefringence technique. Its resistance towards Nd: YAG laser was scrutinized for L-Prolinium Picrate single crystal by applying 1 pulse per second. Different thermal parameters like thermal conductivity, thermal diffusivity, thermal effusivity and specific heat were computed using photo-pyroelectric technique. Solid state parameters were calculated from Clausius Mossotti relation by taking structural information of the title compound. Also, optical parameters like refractive index, reflectance etc were calculated through UV–Vis–NIR analysis. - Highlights: • An optically transparent L-Prolinium Picrate single crystal was harvested from slow evaporation solution growth technique. • The compound shows negative photoconducting nature. • Its optical homogeneity was analyzed using birefringence. • Single shot of laser was applied to sample to measure laser damage threshold value. • The thermal parameters were computed from Photopyroelectric technique.

  6. Nano-optical functionality based on local photoisomerization in photochromic single crystal

    Science.gov (United States)

    Nakagomi, Ryo; Uchiyama, Kazuharu; Kubota, Satoru; Hatano, Eri; Uchida, Kingo; Naruse, Makoto; Hori, Hirokazu

    2018-01-01

    Towards the construction of functional devices and systems using optical near-field processes, we demonstrate the multivalent features in the path-branching phenomena in a photochromic single crystal observed in optical phase change between colorless (1o) and blue-colored (1c) phases that transmits in subwavelength scale over a macroscopic spatial range associated with local mechanical distortions induced. To observe the near-field optical processes of transmission path branching, we have developed a top-to-bottom double-probe scanning near-field optical microscope capable of nanometer-scale correlation measurements by two individually position-controlled probes that face each other sandwiching the photochromic material. We have experimentally confirmed that a local near-field optical excitation applied to one side of the photochromic crystal by a probe tip resulted in characteristic structures of subwavelength scale around 100 nm or less that are observed by the other probe tip located on the opposite side. The structures are different from those resulting from far-field excitations that are quantitively evaluated by autocorrelations. The results suggest that the mechanical distortion caused by the local phase change in the photochromic crystal suppresses the phase change of the neighboring molecules. This new type of optical-near-field-induced local photoisomerization has the potential to allow the construction of functional devices with multivalent properties for natural intelligence.

  7. Towards rhombohedral SiGe epitaxy on 150mm c-plane sapphire substrates

    Science.gov (United States)

    Duzik, Adam J.; Park, Yeonjoon; Choi, Sang H.

    2015-04-01

    Previous work demonstrated for the first time the ability to epitaxially grow uniform single crystal diamond cubic SiGe (111) films on trigonal sapphire (0001) substrates. While SiGe (111) forms two possible crystallographic twins on sapphire (0001), films consisting primarily of one twin were produced on up to 99.95% of the total wafer area. This permits new bandgap engineering possibilities and improved group IV based devices that can exploit the higher carrier mobility in Ge compared to Si. Models are proposed on the epitaxy of such dissimilar crystal structures based on the energetic favorability of crystallographic twins and surface reconstructions. This new method permits Ge (111) on sapphire (0001) epitaxy, rendering Ge an economically feasible replacement for Si in some applications, including higher efficiency Si/Ge/Si quantum well solar cells. Epitaxial SiGe films on sapphire showed a 280% increase in electron mobility and a 500% increase in hole mobility over single crystal Si. Moreover, Ge possesses a wider bandgap for solar spectrum conversion than Si, while the transparent sapphire substrate permits an inverted device structure, increasing the total efficiency to an estimated 30-40%, much higher than traditional Si solar cells. Hall Effect mobility measurements of the Ge layer in the Si/Ge/Si quantum well structure were performed to demonstrate the advantage in carrier mobility over a pure Si solar cell. Another application comes in the use of microelectromechanical devices technology, where high-resistivity Si is currently used as a substrate. Sapphire is a more resistive substrate and offers better performance via lower parasitic capacitance and higher film carrier mobility over the current Si-based technology.

  8. Crystal growth, structural, optical, thermal, mechanical, laser damage threshold and electrical properties of triphenylphosphine oxide 4-nitrophenol (TP4N) single crystals for nonlinear optical applications

    Science.gov (United States)

    Karuppasamy, P.; Senthil Pandian, Muthu; Ramasamy, P.; Verma, Sunil

    2018-05-01

    The optically good quality single crystals of triphenylphosphine oxide 4-nitrophenol (TP4N) with maximum dimension of 15 × 10 × 5 mm3 were grown by slow evaporation solution technique (SEST) at room temperature. The cell dimensions of the grown TP4N crystal were confirmed by single crystal X-ray diffraction (SXRD) and the crystalline purity was confirmed and planes were indexed by powder X-ray diffraction (PXRD) analysis. Functional groups of TP4N crystal were confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical transmittance of the grown crystal was determined by the UV-Vis NIR spectral analysis and it has good optical transparency in the entire visible region. The band tail (Urbach) energy of the grown crystal was analyzed and it appears to be minimum, which indicates that the TP4N has good crystallinity. The position of valence band (Ev) and conduction band (Ec) of the TP4N have been determined from the electron affinity energy (EA) and the ionization energy (EI) of its elements and using the optical band gap. The thermal behaviour of the grown crystal was investigated by thermogravimetric and differential thermal analysis (TG-DTA). Vickers microhardness analysis was carried out to identify the mechanical stability of the grown crystal and their indentation size effect (ISE) was explained by the Meyer's law (ML), Hays-Kendall's (HK) approach, proportional specimen resistance (PSR) model, modified PSR model (MPSR), elastic/plastic deformation (EPD) model and indentation induced cracking (IIC) model. Chemical etching study was carried out to find the etch pit density (EPD) of the grown crystal. Laser damage threshold (LDT) value was measured by using Nd:YAG laser (1064 nm). The dielectric permittivity (ε՛) and dielectric loss (tan δ) as a function of frequency was measured. The electronic polarizability (α) of the TP4N crystal was calculated. It is well matched to the value which was calculated from Clausius-Mossotti relation

  9. Occurrence and elimination of in-plane misoriented crystals in AlN epilayers on sapphire via pre-treatment control

    International Nuclear Information System (INIS)

    Wang Hu; Xiong Hui; Wu Zhi-Hao; Yu Chen-Hui; Tian Yu; Dai Jiang-Nan; Fang Yan-Yan; Zhang Jian-Bao; Chen Chang-Qing

    2014-01-01

    AlN epilayers are grown directly on sapphire (0001) substrates each of which has a low temperature AlN nucleation layer. The effects of pretreatments of sapphire substrates, including exposures to NH 3 /H 2 and to H 2 only ambients at different temperatures, before the growth of AlN epilayers is investigated. In-plane misoriented crystals occur in N-polar AlN epilayers each with pretreatment in a H 2 only ambient, and are characterized by six 60°-apart peaks with splits in each peak in (101-bar 2) phi scan and two sets of hexagonal diffraction patterns taken along the [0001] zone axis in electron diffraction. These misoriented crystals can be eliminated in AlN epilayers by the pretreatment of sapphire substrates in the NH 3 /H 2 ambient. AlN epilayers by the pretreatment of sapphire substrates in the NH 3 /H 2 ambient are Al-polar. Our results show the pretreatments and the nucleation layers are responsible for the polarities of the AlN epilayers. We ascribe these results to the different strain relaxation mechanisms induced by the lattice mismatch of AlN and sapphire. (interdisciplinary physics and related areas of science and technology)

  10. Crucial role of molecular planarity on the second order nonlinear optical property of pyridine based chalcone single crystals

    Science.gov (United States)

    Menezes, Anthoni Praveen; Jayarama, A.; Ng, Seik Weng

    2015-05-01

    An efficient nonlinear optical material 2E-3-(4-bromophenyl)-1-(pyridin-3-yl) prop-2-en-1-one (BPP) was synthesized and single crystals were grown using slow evaporation solution growth technique at room temperature. Grown crystal had prismatic morphology and its structure was confirmed by various spectroscopic studies, elemental analysis, and single crystal X-ray diffraction (XRD) technique. The single crystal XRD of the crystal showed that BPP crystallizes in monoclinic system with noncentrosymmetric space group P21 and the cell parameters are a = 5.6428(7) Å, b = 3.8637(6) Å, c = 26.411(2) Å, β = 97.568(11) deg and v = 575.82(12) Å3. The UV-Visible spectrum reveals that the crystal is optically transparent and has high optical energy band gap of 3.1 eV. The powder second harmonic generation efficiency (SHG) of BPP is 6.8 times that of KDP. From thermal analysis it is found that the crystal melts at 139 °C and decomposes at 264 °C. High optical transparency down to blue region, higher powder SHG efficiency and better thermal stability than that of urea makes this chalcone derivative a promising candidate for SHG applications. Furthermore, effect of molecular planarity on SHG efficiency and role of pyridine ring adjacent to carbonyl group in forming noncentrosymmetric crystal systems of chalcone family is also discussed.

  11. Crystal growth, morphology, thermal and spectral studies of an organosulfur nonlinear optical bis(guanidinium) 5-sulfosalicylate (BG5SS) single crystals

    Science.gov (United States)

    Dhavamurthy, M.; Peramaiyan, G.; Babu, K. Syed Suresh; Mohan, R.

    2015-04-01

    Organosulfur nonlinear optical single crystals of orthorhombic bis(guanidinium) 5-sulfosalicylate (2CH6N3 +·C7H4O6S2-·H2O) with dimension 14 mm × 4 mm × 5 mm have been grown from methanol and water solvents in 1:1 ratio by the slow evaporation growth technique. The crystal structure and morphology of the crystals have been studied by single-crystal X-ray diffraction. FTIR spectroscopic studies were carried out to identify the functional groups and vibrational modes present in the grown crystals. The UV-Vis spectrum was studied to analyze the linear optical properties of the grown crystals. The thermal gravimetric analysis was conducted on the grown crystals, and the result revealed that the grown crystal is thermally stable up to 65 °C. The dielectric tensor components ɛ 11, ɛ 22 and ɛ 33 of BG5SS crystal were evaluated as a function of frequency at 40 °C. The surface laser damage threshold for the grown crystal was measured using Nd:YAG laser. Further, Vickers micro-hardness study was carried out to analyze the mechanical strength of the grown crystals for various loads.

  12. Rise and fall of ferromagnetism in O-irradiated Al2O3 single crystals

    International Nuclear Information System (INIS)

    Li, Qiang; Xu, Juping; Liu, Jiandang; Du, Huaijiang; Ye, Bangjiao

    2015-01-01

    In dilute magnetic semiconductors studies, sapphire was usually used as non-magnetic substrate for films. We observed weak ferromagnetic component in Al 2 O 3 single crystal substrate, and excluded the possibility of ferromagnetic contaminations carefully by inductively coupled plasma mass spectrometry and X-ray photoelectron spectroscopy. The ferromagnetism rise and fall during the process of annealing-oxygen irradiation-annealing of the sapphire. The ferromagnetic changes are consistent with Al-vacancy related defects detected by positron annihilation spectroscopy. With first-principle calculations, we confirm that Al-vacancy can introduce magnetic moment for 3 μB in Al 2 O 3 crystal and form stable V Al -V Al ferromagnetic coupling at room temperature

  13. Low-leakage superconducting tunnel junctions with a single-crystal Al{sub 2}O{sub 3} barrier

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Department of Physics, University of Illinois, Urbana, IL 61801 (United States); Cicak, K; Osborn, K D; Simmonds, R W; Pappas, D P [National Institute of Standards and Technology, Boulder, CO 80305 (United States); McDermott, R; Cooper, K B; Steffen, M; Martinis, J M [University of California, Santa Barbara, CA 93106 (United States)

    2005-10-01

    We have developed a two-step growth scheme for single-crystal Al{sub 2}O{sub 3} tunnel barriers. The barriers are epitaxially grown on single-crystal rhenium (Re) base electrodes that are grown epitaxially on a sapphire substrate, while polycrystalline Al is used as the top electrode. We show that by first growing an amorphous aluminium (Al) oxide layer at room temperature and crystallizing it at a high temperature in oxygen environment, a morphologically intact single-crystal Al{sub 2}O{sub 3} layer is obtained. Tunnel junctions fabricated from these trilayers show very low subgap leakage current. This single-crystal Al{sub 2}O{sub 3} junction may open a new venue for coherent quantum devices.

  14. Sapphire scintillation tests for cryogenic detectors in the Edelweiss dark matter search

    Energy Technology Data Exchange (ETDEWEB)

    Luca, M

    2007-07-15

    Identifying the matter in the universe is one of the main challenges of modern cosmology and astrophysics. An important part of this matter seems to be made of non-baryonic particles. Edelweiss is a direct dark matter search using cryogenic germanium bolometers in order to look for particles that interact very weakly with the ordinary matter, generically known as WIMPs (weakly interacting massive particles). An important challenge for Edelweiss is the radioactive background and one of the ways to identify it is to use a larger variety of target crystals. Sapphire is a light target which can be complementary to the germanium crystals already in use. Spectroscopic characterization studies have been performed using different sapphire samples in order to find the optimum doping concentration for good low temperature scintillation. Ti doped crystals with weak Ti concentrations have been used for systematic X ray excitation tests both at room temperature and down to 30 K. The tests have shown that the best Ti concentration for optimum room temperature scintillation is 100 ppm and 50 ppm at T = 45 K. All concentrations have been checked by optical absorption and fluorescence. After having shown that sapphire had interesting characteristics for building heat-scintillation detectors, we have tested if using a sapphire detector was feasible within a dark matter search. During the first commissioning tests of Edelweiss-II, we have proved the compatibility between a sapphire heat scintillation detector and the experimental setup. (author)

  15. Studies of Second Order Optical Nonlinearities of 4-Aminobenzophenone (ABP) Single Crystal Films

    Science.gov (United States)

    Bhowmik, Achintya; Thakur, Mrinal

    1998-03-01

    Specific organic materials exhibit very high second order optical susceptibilities. Growth of single crystal films of these materials and characterization of nonlinear optical properties are necessary for implementation of device applications. We have grown large-area films ( 1 cm^2 area, 4 μm thick) of ABP by a modification of the shear method. Single crystal nature of the films was confirmed by polarized optical microscopy. X-ray diffraction analysis showed a [100] surface orientation. The absorption spectra revealed transparency from 390 nm to 1940 nm. Significant elements of the second order optical susceptibility tensor were measured by detailed SHG experiments using a Nd:YAG laser (1064 nm, 100 ps, 82 MHz). Second-harmonic power was measured using lock-in detection with carefully selected polarization conditions while the film was rotated about the propagation direction. Using LiNbØas the reference, d-coefficients of ABP were found to be d_23=7.2 pm/V and d_22=0.7 pm/V. Type-I and type-II phase-matching directions were identified on the film by analyzing the optical indicatrix surfaces at fundamental and second-harmonic frequencies.

  16. Transformation of a Plane Wavefront in Hemispherical Lenses Made of Leuco-Sapphire

    Science.gov (United States)

    Vetrov, V. N.; Ignatenkov, B. A.; Yakobson, V. E.

    2018-01-01

    An algorithm for wavefront calculation of ordinary and extraordinary waves after propagation through hemispherical components made of a uniaxial crystal is developed. The influence of frequency dispersion of n o and n e , as well as change in the direction of the optic axis of the crystal, on extraordinary wavefront in hemispheres made of from leuco-sapphire and a plastically deformed analog thereof is determined.

  17. Direct pumping of ultrashort Ti:sapphire lasers by a frequency doubled diode laser

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2011-01-01

    electro-optical efficiency of the diode laser. Autocorrelation measurements show that pulse widths of less than 20 fs can be expected with an average power of 52 mW when using our laser. These results indicate the high potential of direct diode laser pumped Ti: sapphire lasers to be used in applications....... When using our diode laser system, the optical conversion efficiencies from green to near-infrared light reduces to 75 % of the values achieved with the commercial pump laser. Despite this reduction the overall efficiency of the Ti: sapphire laser is still increased by a factor > 2 due to the superior...... like retinal optical coherence tomography (OCT) or pumping of photonic crystal fibers for CARS (coherent anti-stokes Raman spectroscopy) microscopy....

  18. Optical properties of GaS:Ho3+ and GaS:Tm3+ single crystals

    International Nuclear Information System (INIS)

    Jin, Moon-Seog; Kim, Chang-Dae; Kim, Wha-Tek

    2004-01-01

    GaS:Ho 3+ and GaS:Tm 3+ single crystals were grown by using the chemical transport reaction method. We measured the optical absorption, the infra-red absorption, and the photoluminescence spectra of the single crystals. The direct and the indirect energy band gaps of the single crystals at 13 K were identified. Infra-red absorption peaks at 6 K appeared in the single crystals. Broad emission bands at 6 K were observed at 464 nm and 580 nm for GaS:Ho 3+ and 462 nm and 581 nm for GaS:Tm 3+ . These broad emission bands were identified as originating from donor-acceptor pair recombinations. Sharp emission peak groups were observed near 435 nm, 495 nm, and 660 nm for GaS:Ho 3+ and near 672 nm for GaS:Tm 3+ . These sharp emission peak groups were identified as being due to the electron transitions between the energy levels of Ho 3+ and Tm 3+ . Especially, white photoluminescence was obtained in the GaS:Ho 3+ single crystal.

  19. Phonon anomalies in optical spectra of LiNbO3 single crystals

    Directory of Open Access Journals (Sweden)

    ANDREJA VALCIC

    2004-06-01

    Full Text Available LiNbO3 single crystals were grown by the Czochralski technique in an air atmosphere. The critical crystal diameter Dc = 1.5 cm and the critical rate of rotation wc = 35 rpm were calculated by equations from the hydrodynamics of the melt. The domain inversion was carried out at 1430 K using a 3.75 V/cm electric field for 10 min. The obtained crystals were cut, polished and etched to determine the presence of dislocations and single domain structures. The optical properties were studied by infrared and Raman spectroscopy as a function of temperature. With decreasing temperature, an atypical behaviour of the phonon modes could be seen in the ferroelectrics LiNbO3. The obtained results are discussed and compared with published data.

  20. Growth, spectral and optical characterization of a novel nonlinear optical organic material: D-Alanine DL-Mandelic acid single crystal

    Science.gov (United States)

    Jayaprakash, P.; Mohamed, M. Peer; Caroline, M. Lydia

    2017-04-01

    An organic nonlinear optical single crystal, D-alanine DL-mandelic acid was synthesized and successfully grown by slow evaporation solution growth technique at ambient temperature using solvent of aqueous solution. The unit cell parameters were assessed from single crystal X-ray diffraction analysis. The presence of diverse functional groups and vibrational modes were identified using Fourier Transform Infra Red and Fourier Transform Raman spectral analyses. The chemical structure of grown crystal has been identified by Nuclear Magnetic Resonance spectroscopic study. Ultraviolet-visible spectral analysis reveal that the crystal has lower cut-off wavelength down to 259 nm, is a key factor to exhibit second harmonic generation signal. The electronic optical band gap and Urbach energy is calculated as 5.31 eV and 0.2425 eV respectively from the UV absorption profile. The diverse optical properties such as, extinction coefficient, reflectance, linear refractive index, optical conductivity was calculated using UV-visible data. The relative second harmonic efficiency of the compound is found to be 0.81 times greater than that of KH2PO4 (KDP). The thermal stability of the grown crystal was studied by thermogravimetric analysis and differential thermal analysis techniques. The luminescence spectrum exhibited two peaks (520 nm, 564 nm) due to the donation of protons from carboxylic acid to amino group. The Vickers microhardness test was carried out employing one of the as-grown hard crystal and there by hardness number (Hv), Meyer's index (n), yield strength (σy), elastic stiffness constant (C11) and Knoop hardness number (HK) were assessed. The dielectric behaviour of the as-grown crystal was analyzed for different temperatures (313 K, 333 K, 353 K, and 373 K) at different frequencies.

  1. Design of all solid state tunable single-mode Ti: sapphire laser for nuclear industry

    International Nuclear Information System (INIS)

    Lee, J.H.; Nam, S.M.; Lee, Y.J.; Lee, J.M.; Horn, Roland E.; Wendt, Klaus

    1999-01-01

    We designed a Ti:Sapphire laser pumped by a diode laser pumped solid state laser (DPSSL). The DPSSL was intra-cavity frequency doubled and it had 20 W output power. The Ti:Sapphire laser was designed for single longitudinal mode lasing. For single mode lasing, the laser used several solid etalons. We simulated temporal evolution of the laser pulse and single pass amplification rate of the photons in each modes from rate equations. From the result, we found that single mode lasing is viable in this cavity

  2. Chiral multichromic single crystals for optical devices (LDRD 99406).

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Richard Alan; Felix, Ana M. (University of New Mexico, Albuquerque, NM)

    2006-12-01

    This report summarizes our findings during the study of a novel system that yields multi-colored materials as products. This system is quite unusual as it leads to multi-chromic behavior in single crystals, where one would expect that only a single color would exist. We have speculated that these novel solids might play a role in materials applications such as non-linear optics, liquid crystal displays, piezoelectric devices, and other similar applications. The system examined consisted of a main-group alkyl compound (a p block element such as gallium or aluminum) complexed with various organic di-imines. The di-imines had substituents of two types--either alkyl or aromatic groups attached to the nitrogen atoms. We observed that single crystals, characterized by X-ray crystallography, were obtained in most cases. Our research during January-July, 2006, was geared towards understanding the factors leading to the multi-chromic nature of the complexes. The main possibilities put forth initially considered (a) the chiral nature of the main group metal, (b) possible reduction of the metal to a lower-valent, radical state, (c) the nature of the ligand(s) attached to the main group metal, and (d) possible degradation products of the ligand leading to highly-colored products. The work carried out indicates that the most likely explanation considered involves degradation of the aromatic ligands (a combination of (c) and (d)), as the experiments performed can clearly rule out (a) and (b).

  3. Bulk crystal growth and nonlinear optical characterization of semiorganic single crystal: Cadmium (II) dibromide L - Proline monohydrate

    Energy Technology Data Exchange (ETDEWEB)

    Balakrishnan, T., E-mail: balacrystalgrowth@gmail.com [Crystal Growth Laboratory, PG & Research Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023, Tamil Nadu (India); Sathiskumar, S. [Crystal Growth Laboratory, PG & Research Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023, Tamil Nadu (India); Ramamurthi, K. [Crystal Growth and Thin Film Laboratory, Department of Physics and Nanotechnology, SRM University, Kattankulathur, 603 203, Kancheepuram, Tamil Nadu (India); Thamotharan, S. [Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA University, Thanjavur, 613 401 (India)

    2017-01-15

    Single crystal of a novel metal organic nonlinear optical (NLO) cadmium (II) dibromide L - proline monohydrate (CBLPM) of size 7 × 7 × 5 mm{sup 3} was grown from slow evaporation technique. Single crystal X – ray diffraction analysis reveals that the crystal belongs to orthorhombic system with lattice parameters a = 10.1891 (8) Å, b = 13.4961 (11) Å, c = 7.4491 (5) Å and space group P2{sub 1}2{sub 1}2{sub 1}. The powder X – ray diffraction pattern of CBLPM was recorded and the X – ray diffraction peaks were indexed. The various functional groups of CBLPM were identified by the FT – IR and FT – Raman spectral analyses. The optical transmittance window and lower cut off wavelength of CBLPM were identified from UV – Vis – NIR studies. The mechanical strength of the grown crystal was estimated using Vickers microhardness test. Dielectric constant and dielectric loss measurements were carried out at different temperatures in the frequency range of 50 Hz - 2 MHz. The photoluminescence spectrum was recorded in the wavelength range 200–400 nm and the estimated optical band gap was ∼4.1 eV. Etching studies were carried out for different etching time. Thermal stability of CBLPM was determined using thermogravimetric analysis. Laser induced damage threshold study was carried out for the grown crystal using Nd:YAG laser. Size dependent second harmonic generation efficiency of the grown crystal was determined by Kurtz and Perry powder technique with different particle size using Nd:YAG laser with wavelength 1064 nm. Second harmonic generation efficiency of the powdered CBLPM crystal was ∼2.3 times that of potassium dihydrogen orthophosphate. - Highlights: • CBLPM crystal belongs to orthorhombic crystal system with space group P2{sub 1}2{sub 1}2{sub 1.} • Transmittance of CBLPM is ∼80% in the 650–1100 nm range. • Powder SHG efficiency of CBLPM increases with increase in particle size. • SHG efficiency of 0.57 μm size powdered CBLPM is ∼2

  4. Principles of crystallization, and methods of single crystal growth

    International Nuclear Information System (INIS)

    Chacra, T.

    2010-01-01

    Most of single crystals (monocrystals), have distinguished optical, electrical, or magnetic properties, which make from single crystals, key elements in most of technical modern devices, as they may be used as lenses, Prisms, or grating sin optical devises, or Filters in X-Ray and spectrographic devices, or conductors and semiconductors in electronic, and computer industries. Furthermore, Single crystals are used in transducer devices. Moreover, they are indispensable elements in Laser and Maser emission technology.Crystal Growth Technology (CGT), has started, and developed in the international Universities and scientific institutions, aiming at some of single crystals, which may have significant properties and industrial applications, that can attract the attention of international crystal growth centers, to adopt the industrial production and marketing of such crystals. Unfortunately, Arab universities generally, and Syrian universities specifically, do not give even the minimum interest, to this field of Science.The purpose of this work is to attract the attention of Crystallographers, Physicists and Chemists in the Arab universities and research centers to the importance of crystal growth, and to work on, in the first stage to establish simple, uncomplicated laboratories for the growth of single crystal. Such laboratories can be supplied with equipment, which are partly available or can be manufactured in the local market. Many references (Articles, Papers, Diagrams, etc..) has been studied, to conclude the most important theoretical principles of Phase transitions,especially of crystallization. The conclusions of this study, are summarized in three Principles; Thermodynamic-, Morphologic-, and Kinetic-Principles. The study is completed by a brief description of the main single crystal growth methods with sketches, of equipment used in each method, which can be considered as primary designs for the equipment, of a new crystal growth laboratory. (author)

  5. Growth and physicochemical properties of second-order nonlinear optical 2-amino-5-chloropyridinium trichloroacetate single crystals

    Science.gov (United States)

    Renugadevi, R.; Kesavasamy, R.

    2015-09-01

    The growth of organic nonlinear optical (NLO) crystal 2-amino-5-chloropyridinium trichloroacetate (2A5CPTCA) has been synthesized and single crystals have been grown from methanol solvent by slow evaporation technique. The grown crystals were subjected to various characterization analyses in order to find out the suitability for device fabrication. Single crystal X-ray diffraction analysis reveals that 2A5CPTCA crystallizes in monoclinic system with the space group Cc. The grown crystal was further characterized by Fourier transform infrared spectral analysis to find out the functional groups. The nuclear magnetic resonance spectroscopy is a research technique that exploits the magnetic properties of certain atomic nuclei. The optical transparency window in the visible and near-IR (200--1100 nm) regions was found to be good for NLO applications. Thermogravimetric analysis and differential thermal analysis were used to study its thermal properties. The powder second harmonic generation efficiency measurement with Nd:YAG laser (1064 nm) radiation shows that the highest value when compared with the standard potassium dihydrogen phosphate crystal.

  6. (211) oriented ZnTe growth on m-plane sapphire by MBE

    Energy Technology Data Exchange (ETDEWEB)

    Nakasu, Taizo [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kobayashi, Masakazu [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, 2-8-26, Tokyo 169-0051 (Japan); Togo, Hiroyoshi [NTT Microsystem Integration Laboratories, Atugi-shi 243-0198 (Japan); Asahi, Toshiaki [Technology Development Center, JX Nippon Mining and Metals Corporation, Hitachi-shi 317-0056 (Japan)

    2013-11-15

    Single-crystalline and single domain ZnTe thin films are sought for high-performance terahertz wave detectors, and ZnTe/sapphire heterostructures were considered since the Electro-Optical (EO) effect could be obtained only from epilayers. ZnTe epilayers were grown on m-plane sapphire substrates by molecular beam epitaxy, and the potential of single domain epilayers was explored. Through the X-ray diffraction pole figure measurement it was confirmed that one (100) oriented ZnTe domain along with two kinds of (211) oriented domains were formed on the m-plane sapphire when the layer was grown at 340 C. When the layer was grown at 350 C, the (211) oriented domain dominated the film. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Investigation of inorganic nonlinear optical potassium penta borate tetra hydrate (PPBTH) single crystals grown by slow evaporation method

    Science.gov (United States)

    Arivuselvi, R.; Babu, P. Ramesh

    2018-03-01

    Borates family crystals were plays vital role in the field of non linear optics (NLO) due to needs of wide range of applications. In this report, NLO crystals (potassium penta borate tetra hydrate (KB5H8O12) are grown by slow evaporation method at room temperature (28° C) and studied their physical properties. The harvested single crystals are transparent with the dimension of 12 × 10 × 6 mm3 and colourless. X-ray diffraction of single crystals reveals that the grown crystal belongs to orthorhombic system with non-centrosymmetric space group Pba2. All the absorbed functional groups are present in the order of inorganic compounds expect 1688 cm-1 because of water (Osbnd H sbnd O blending) molecule present in the pristine. Crystals show transparent in the entire visible region with 5.9 eV optical band gap and also it shows excellence in both second and third order nonlinear optical properties. Crystals can withstand upto 154 °C without any phase changes which is observed using thermal (TGA/DTA) analysis.

  8. Optical Properties of the Fresnoite Ba2TiSi2O8 Single Crystal

    Directory of Open Access Journals (Sweden)

    Chuanying Shen

    2017-02-01

    Full Text Available In this work, using large-sized single crystals of high optical quality, the optical properties of Ba2TiSi2O8 were systematically investigated, including transmission spectra, refractive indices and nonlinear absorption properties. The crystal exhibits a high transmittance (>84% over a wide wavelength range from 340 to 2500 nm. The refractive indices in the range from 0.31256 to 1.01398 μm were measured, and Sellmeier’s equations were fitted by the least squares method. The nonlinear absorption properties were studied by using the open-aperture Z-scan technique, with a nonlinear absorption coefficient measured to be on the order of 0.257 cm/GW at the peak power density of 16.4 GW/cm2. Such high transmittance and wide transparency indicate that optical devices using the Ba2TiSi2O8crystal can be applied over a wide wavelength range. Furthermore, the small nonlinear absorption observed in Ba2TiSi2O8 will effectively increase the optical conversion efficiency, decreasing the generation of laser damage of the optical device.

  9. Thermal, mechanical, optical and dielectric properties of piperazinium hydrogen phosphite monohydrate NLO single crystal

    Science.gov (United States)

    Rajkumar, R.; Praveen Kumar, P.

    2018-05-01

    Optical transparent crystal of piperazinium hydrogen phosphite monohydrate (PHPM) was grown by slow evaporation method. The grown crystal was characterized by single crystal X-ray diffraction analysis and the crystal belongs to monoclinic system. The functional groups present in PHPM crystal were confirmed by FTIR analysis. UV-Visible spectrum shows that the PHPM crystal is transparent in the visible region. The mechanical behavior of PHPM crystal was characterized by Vickers hardness test. Thermal stability of PHPM crystal was analyzed by thermogravimetric analysis. Dielectric studies were also carried out for the grown crystal. The third-order nonlinear parameters such as nonlinear refractive index and nonlinear absorption coefficient have been calculated using Z scan technique.

  10. Influence of VO2+ ions on structural and optical properties of potassium succinate-succinic acid single crystal for non-linear optical applications

    Science.gov (United States)

    Juliet sheela, K.; Subramanian, P.

    2018-04-01

    A transparent and good optical quality semi organic single crystal of vanadium doped potassium succinate-succinic acid (KSSA) was synthesized by slow evaporation technique at room temperature. The structural perfection was supported by the powder XRD of the KSSA-VO2+ single crystal. Optical behavior of the material was discovered from the absorption and transmission spectra of UV-vis-NIR characterization. Functional group and presence of metal ion in the specimen are depicted from FTIR traces. From the photoluminescence studies, emission of wavelength in the violet region (418 nm) at the excitation of 243 nm could be ascertained. EDAX, SEM measurements identify presence of elements and pictures the step-line growth and the imperfection presents in the grown crystal. EPR analysis extracts the information about the local site symmetry around the impurity ion, molecular orbital coefficients, admixture coefficients and ground state wave function of VO2+ doped KSSA single crystal. Second harmonic generation (SHG) efficiency of the grown crystal was investigated to explore the NLO characteristic of the material.

  11. Study of the effect of doping on the temperature stability of the optical properties of germanium single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Podkopaev, O. I. [Joint-Stock Company “Germanium” (Russian Federation); Shimanskiy, A. F., E-mail: shimanaf@mail.ru [Siberian Federal University (Russian Federation); Kopytkova, S. A.; Filatov, R. A. [Joint-Stock Company “Germanium” (Russian Federation); Golubovskaya, N. O. [Siberian Federal University (Russian Federation)

    2016-10-15

    The effect of doping on the optical transmittance of germanium single crystals is studied by infrared Fourier spectroscopy. It is established that the introduction of silicon and tellurium additives into germanium doped with antimony provides a means for improving the temperature stability of the optical properties of the crystals.

  12. Study of the effect of doping on the temperature stability of the optical properties of germanium single crystals

    International Nuclear Information System (INIS)

    Podkopaev, O. I.; Shimanskiy, A. F.; Kopytkova, S. A.; Filatov, R. A.; Golubovskaya, N. O.

    2016-01-01

    The effect of doping on the optical transmittance of germanium single crystals is studied by infrared Fourier spectroscopy. It is established that the introduction of silicon and tellurium additives into germanium doped with antimony provides a means for improving the temperature stability of the optical properties of the crystals.

  13. Bulk crystal growth and their effective third order nonlinear optical properties of 2-(4-fluorobenzylidene) malononitrile (FBM) single crystal

    Science.gov (United States)

    Priyadharshini, A.; Kalainathan, S.

    2018-04-01

    2-(4-fluorobenzylidene) malononitrile (FBM), an organic third order nonlinear (TONLO) single crystal with the dimensions of 32 × 7 × 11 mm3, has been successfully grown in acetone solution by slow evaporation technique at 35 °C. The crystal system (triclinic), space group (P-1) and crystalline purity of the titular crystal were measured by single crystal and powder X-ray diffraction, respectively. The molecular weight and the multiple functional groups of the FBM material were confirmed through the mass and FT-IR spectral analysis. UV-Vis-NIR spectral study enroles that the FBM crystal exhibits excellent transparency (83%) in the entire visible and near infra-red region with a wide bandgap 2.90 eV. The low dielectric constant (εr) value of FBM crystal is appreciable for microelectronics industry applications. Thermal stability and melting point (130.09 °C) were ascertained by TGA-DSC analysis. The laser-induced surface damage threshold (LDT) value of FBM specimen is found to be 2.14 GW/cm2, it is fairly good compared to other reported NLO crystals. The third - order nonlinear optical character of the FBM crystal was confirmed through the typical single beam Z-scan technique. All these finding authorized that the organic crystal of FBM is favorably suitable for NLO applications.

  14. Optical properties of Ni-doped MgGa2O4 single crystals grown by floating zone method

    International Nuclear Information System (INIS)

    Suzuki, Takenobu; Hughes, Mark; Ohishi, Yasutake

    2010-01-01

    The single crystal growth conditions and spectroscopic characterization of Ni-doped MgGa 2 O 4 with inverse-spinel structure crystal family are described. Single crystals of this material have been grown by floating zone method. Ni-doped MgGa 2 O 4 single crystals have broadband fluorescence in the 1100-1600 nm wavelength range, 1.6 ms room temperature lifetime, 56% quantum efficiency and 1.05x10 -21 cm 2 stimulated emission cross section at the emission peak. This new material is very promising for tunable laser applications covering the important optical communication and eye safe wavelength region.

  15. Optical and electrical properties of ZrSe3 single crystals grown by chemical vapour transport technique

    International Nuclear Information System (INIS)

    Patel, Kaushik; Prajapati, Jagdish; Vaidya, Rajiv; Patel, S.G.

    2005-01-01

    Single crystals of the lamellar compound, ZrSe 3 , were grown by chemical vapour transport technique using iodine as a transporting agent. The grown crystals were characterized with the help of energy dispersive analysis by X-ray (EDAX), which gave confirmation about the stoichiometry. The optical band gap measurement of as grown crystals was carried out with the help of optical absorption spectra in the range 700-1450 nm. The indirect as well as direct band gap of ZrSe 3 were found to be 1.1 eV and 1.47 eV, respectively. The resistivity of the as grown crystals was measured using van der Pauw method. The Hall parameters of the grown crystals were determined at room temperature from Hall effect measurements. Electrical resistivity measurements were performed on this crystal in the temperature range 303-423 K. The crystals were found to exhibit semiconducting nature in this range. The activation energy and anisotropy measurements were carried out for this crystal. Pressure dependence of electrical resistance was studied using Bridgman opposed anvils set up up to 8 GPa. The semiconducting nature of ZrSe 3 single crystal was inferred from the graph of resistance vs pressure. The results obtained are discussed in detail. (author)

  16. Synthesis, growth, structure, mechanical and optical properties of a new semi-organic 2-methyl imidazolium dihydrogen phosphate single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Nagapandiselvi, P., E-mail: nagapandiselvip@ssn.edu.in [Department of Physics, SSN College of Engineering, Kalavakkam (India); Baby, C. [Sophisticated Analytical Instrument Facility, Indian Institute of Technology Madras, Chennai (India); Gopalakrishnan, R. [Crystal Research Lab, Department of Physics, Anna University, Chennai (India)

    2016-09-15

    Highlights: • 2MIDP crystals were grown by slow evaporation solution growth technique. • Single crystal XRD revealed self-assembled supramolecular framework. • Z scan technique is employed for third order nonlinear optical susceptibility. • Structure-property correlation is established. - Abstract: A new semi-organic compound, 2-methyl imidazolium dihydrogen phosphate (2MIDP), was prepared and good quality single crystals of 2MIDP were grown by slow evaporation solution growth technique. Crystal structure elucidated using Single crystal XRD showed that 2MIDP crystallizes in monoclinic system with P2{sub 1}/c space group. FT-IR, UV-Vis-NIR, Fluorescence and FT-NMR spectra confirm the molecular structure of 2MIDP. The UV-Vis-NIR spectra established the suitability of the compound for NLO applications. TG-DSC showed that 2MIDP is thermally stable up to 200 °C. Mechanical characteristics like hardness number (H{sub v}), stiffness constant (C{sub 11}), yield strength (σ{sub v}), fracture toughness (K{sub c}) and brittleness index (B{sub i}) were assessed using Vicker’s microhardness tester. Third order nonlinear optical properties determined from Z-scan measurement using femto and picosecond lasers showed two photon reverse saturable absorption. The enhancement of nonlinear optical properties in femto second laser, revealed the suitability of 2MIDP for optical limiting applications.

  17. Crystal orientation dependence of the optical bandgap of (1 - x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystals

    International Nuclear Information System (INIS)

    Wan Xinming; Zhao Xiangyong; Chan, H.L.W.; Choy, C.L.; Luo Haosu

    2005-01-01

    The transmission spectra of rhombohedral 0.71Pb(Mg 1/3 Nb 2/3 )O 3 -0.29PbTiO 3 (PMN-0.29PT) and tetragonal PMN-0.38PT single crystals were obtained in the main crystallographic directions , and . The absorption coefficients were computed and the optical bandgaps were calculated in both direct and indirect transitions. The energy of phonons contributing in the indirect transition was also calculated. For PMN-0.38PT single crystal in all the three directions, the values of direct bandgaps E gd are all slightly lower than those of PMN-0.29PT single crystal, while the indirect bandgaps E gi are all higher. For different crystallographic directions, the values of E gi for -direction are lower compared with and directions, both for PMN-0.29PT and PMN-0.38PT single crystals. Some discussions about the B-site cation d-orbits and the O-anion 2p orbits that determine the basic energy level of the single crystals are presented. The optical transition mechanism was also discussed

  18. Mapping the Local Density of Optical States of a Photonic Crystal with Single Quantum Dots

    DEFF Research Database (Denmark)

    Wang, Qin; Stobbe, Søren; Lodahl, Peter

    2011-01-01

    We use single self-assembled InGaAs quantum dots as internal probes to map the local density of optical states of photonic crystal membranes. The employed technique separates contributions from nonradiative recombination and spin-flip processes by properly accounting for the role of the exciton...... fine structure. We observe inhibition factors as high as 70 and compare our results to local density of optical states calculations available from the literature, thereby establishing a quantitative understanding of photon emission in photonic crystal membranes. © 2011 American Physical Society....

  19. Size characterisation of noble-metal nano-crystals formed in sapphire by ion irradiation and subsequent thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Mota-Santiago, Pablo-Ernesto [Instituto de Fisica, Universidad Nacional Autonoma de Mexico A.P. 20-364 01000 Mexico D.F. (Mexico); Crespo-Sosa, Alejandro, E-mail: crespo@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico A.P. 20-364 01000 Mexico D.F. (Mexico); Jimenez-Hernandez, Jose-Luis; Silva-Pereyra, Hector-Gabriel; Reyes-Esqueda, Jorge-Alejandro; Oliver, Alicia [Instituto de Fisica, Universidad Nacional Autonoma de Mexico A.P. 20-364 01000 Mexico D.F. (Mexico)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Systematic study on the formation of Ag and Au nano-particles in Al{sub 2}O{sub 3}. Black-Right-Pointing-Pointer Annealing in a reducing atmosphere, below the metal melting point is more suitable. Black-Right-Pointing-Pointer Au nano-particles grow up to 15 nm and Ag nano-particles up to 45 nm in radius. Black-Right-Pointing-Pointer Ostwald ripening is the mechanism responsible for the formation of large nanoparticles. Black-Right-Pointing-Pointer Optical properties of metallic nano-particles in Al{sub 2}O{sub 3} can be related to their size. - Abstract: Metallic nano-particles embedded in transparent dielectrics are very important for new technological applications because of their unique optical properties. These properties depend strongly on the size and shape of the nano-particles. In order to achieve the synthesis of metallic nano-particles it has been used the technique of ion implantation. This is a very common technique because it allows the control of the depth and concentration of the metallic ions inside the sample, limited mostly by straggling, without introducing other contaminant agents. The purpose of this work was to measure the size of the nano-particles grown under different conditions in Sapphire and its size evolution during the growth process. To achieve this goal, {alpha}-Al{sub 2}O{sub 3} single crystals were implanted with Ag or Au ions at room temperature with different fluences (from 2 Multiplication-Sign 10{sup 16} ions/cm{sup 2} to 8 Multiplication-Sign 10{sup 16} ions/cm{sup 2}). Afterwards, the samples were annealed at different temperatures (from 600 Degree-Sign C to 1100 Degree-Sign C) in oxidising, reducing, Ar or N{sub 2} atmospheres. We measured the ion depth profile by Rutherford Backscattering Spectroscopy (RBS) and the nano-crystals size distribution by using two methods, the surface plasmon resonance in the optical extinction spectrum and the Transmission Electron Microscopy (TEM).

  20. Optical characteristics of BaGa2S4:Ho3+ and BaGa2Se4:Ho3+ single crystals

    International Nuclear Information System (INIS)

    Choe, Sung-Hyu; Jin, Moon-Seog; Kim, Wha-Tek

    2005-01-01

    BaGa 2 S 4 , BaGa 2 S 4 :Ho 3+ , BaGa 2 Se 4 , and BaGa 2 Se 4 :Ho 3+ single crystals were grown by using the chemical transport reaction method. The optical energy gaps of the single crystals were investigated in the temperature region from 11 K to 300 K. The temperature dependence of the optical energy gap was well fitted by the Varshni equation. Two broad emission bands were observed in the photoluminescence spectra of the single crystals. These bands were attributed to donor-acceptor pair recombinations. Sharp emission peaks were observed in the BaGa 2 S 4 :Ho 3+ and the BaGa 2 Se 4 :Ho 3+ single crystals and were assigned to radiation recombination between split Stark levels of Ho 3+ .

  1. MBE growth and characterization of ZnTe epilayers on m-plane sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Nakasu, Taizo; Sun, Wei-Che; Yamashita, Sotaro; Aiba, Takayuki; Taguri, Kosuke [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kobayashi, Masakazu [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, 2-8-26, Tokyo 169-0051 (Japan); Asahi, Toshiaki [Technology Development Center, JX Nippon Mining and Metals Corporation, Hitachi 317-0056 (Japan); Togo, Hiroyoshi [NTT Microsystem Integration Laboratories, Atsugi 243-0198 (Japan)

    2014-07-15

    ZnTe epilayers were grown on transparent (10-10) oriented (m -plane) sapphire substrates by molecular beam epitaxy (MBE). Pole figure imaging was used to study the domain distribution within the layer. (211)-oriented ZnTe domains were formed on m -plane sapphire. The presence of only one kind of (211) ZnTe domain formed on the 2 -tilted m -plane sapphire substrates was confirmed. Thus, single domain (211) ZnTe epilayers can be grown on the m -plane sapphire using MBE. Although differences in the crystal structure and lattice mismatch are large, precise control of the substrate surface lattice arrangement result in the formation of high-quality epitaxial layers. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Crystal orientation mechanism of ZnTe epilayers formed on different orientations of sapphire substrates by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Nakasu, T.; Yamashita, S.; Aiba, T.; Hattori, S.; Sun, W.; Taguri, K.; Kazami, F.; Kobayashi, M.

    2014-01-01

    The electrooptic effect in ZnTe has recently attracted research attention, and various device structures using ZnTe have been explored. For application to practical terahertz wave detector devices based on ZnTe thin films, sapphire substrates are preferred because they enable the optical path alignment to be simplified. ZnTe/sapphire heterostructures were focused upon, and ZnTe epilayers were prepared on highly mismatched sapphire substrates by molecular beam epitaxy. Epitaxial relationships between the ZnTe thin films and the sapphire substrates with their various orientations were investigated using an X-ray diffraction pole figure method. (0001) c-plane, (1-102) r-plane, (1-100) m-plane, and (11-20) a-plane oriented sapphire substrates were used in this study. The epitaxial relationship between ZnTe and c-plane sapphire was found to be (111) ZnTe//(0001) sapphire with an in-plane orientation relationship of [−211] ZnTe//[1-100] sapphire. It was found that the (211)-plane ZnTe layer was grown on the m-plane of the sapphire substrates, and the (100)-plane ZnTe layer was grown on the r-plane sapphire. When the sapphire substrates were inclined from the c-plane towards the m-axis direction, the orientation of the ZnTe thin films was then tilted from the (111)-plane to the (211)-plane. The c-plane of the sapphire substrates governs the formation of the (111) ZnTe domain and the ZnTe epilayer orientation. These crystallographic features were also related to the atom arrangements of ZnTe and sapphire.

  3. High-quality single crystalline NiO with twin phases grown on sapphire substrate by metalorganic vapor phase epitaxy

    Directory of Open Access Journals (Sweden)

    Kazuo Uchida

    2012-12-01

    Full Text Available High-quality single crystalline twin phase NiO grown on sapphire substrates by metalorganic vapor phase epitaxy is reported. X-ray rocking curve analysis of NiO films grown at different temperatures indicates a minimum full width at half maximum of the cubic (111 diffraction peak of 0.107° for NiO film grown at as low as 550 °C. Detailed microstructural analysis by Φ scan X-ray diffraction and transmission electron microscopy reveal that the NiO film consists of large single crystalline domains with two different crystallographic orientations which are rotated relative to each other along the [111] axis by 60°. These single crystal domains are divided by the twin phase boundaries.

  4. Rise and fall of ferromagnetism in O-irradiated Al{sub 2}O{sub 3} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qiang [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei 230026 (China); China Spallation Neutron Source, Institute of High Energy Physics, Chinese Academy of Sciences, Dongguan 523803 (China); Xu, Juping; Liu, Jiandang; Du, Huaijiang; Ye, Bangjiao, E-mail: bjye@ustc.edu.cn [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei 230026 (China)

    2015-06-21

    In dilute magnetic semiconductors studies, sapphire was usually used as non-magnetic substrate for films. We observed weak ferromagnetic component in Al{sub 2}O{sub 3} single crystal substrate, and excluded the possibility of ferromagnetic contaminations carefully by inductively coupled plasma mass spectrometry and X-ray photoelectron spectroscopy. The ferromagnetism rise and fall during the process of annealing-oxygen irradiation-annealing of the sapphire. The ferromagnetic changes are consistent with Al-vacancy related defects detected by positron annihilation spectroscopy. With first-principle calculations, we confirm that Al-vacancy can introduce magnetic moment for 3 μB in Al{sub 2}O{sub 3} crystal and form stable V{sub Al}-V{sub Al} ferromagnetic coupling at room temperature.

  5. Numerical investigation of thermal and residual stress of sapphire during c-axis vertical Bridgman growth process considering the solidification history effect

    Science.gov (United States)

    Hwang, Ji Hoon; Lee, Young Cheol; Lee, Wook Jin

    2018-01-01

    Sapphire single crystals have been highlighted for epitaxial of gallium nitride films in high-power laser and light emitting diode industries. In this study, the evolution of thermally induced stress in sapphire during the vertical Bridgman crystal growth process was investigated using a finite element model that simplified the real Bridgman process. A vertical Bridgman process of cylindrical sapphire crystal with a diameter of 50 mm was considered for the model. The solidification history effect during the growth was modeled by the quite element technique. The effects of temperature gradient, seeding interface shape and seeding position on the thermal stress during the process were discussed based on the finite element analysis results.

  6. Electric-field gradient characterization at 181Ta impurities in sapphire single crystals

    International Nuclear Information System (INIS)

    Renteria, M.; Darriba, G.N.; Errico, L.A.; Munoz, E.L.; Eversheim, P.D.

    2005-01-01

    We report Perturbed-Angular-Correlation (PAC) experiments on corundum Al 2 O 3 single crystals implanted with 181 Hf/ 181 Ta ions at the ISKP at Bonn and measured at La Plata with high efficiency and time-resolution. The magnitude, asymmetry, and orientation (with respect to the crystalline axes) of the electric-field gradient (EFG) tensor were determined measuring the spin-rotation curves as a function of different orientations of the single crystals relative to the detector system. These results are analyzed in the framework of point-charge model and ab initio Full-Potential Linearized-Augmented Plane Wave calculations, and compared with EFG results coming from PAC experiments with 111 In/ 111 Cd impurities. This combined study enables the determination of lattice relaxations induced by the presence of the impurity and the state of charge of a deep impurity donor level in the band gap of the semiconductor. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Sapphire: A kinking nonlinear elastic solid

    Science.gov (United States)

    Basu, S.; Barsoum, M. W.; Kalidindi, S. R.

    2006-03-01

    Kinking nonlinear elastic (KNE) solids are a recently identified large class of solids that deform fully reversibly by the formation of dislocation-based kink bands [Barsoum et al. Phys. Rev. Lett. 92, 255508 (2004)]. We further conjectured that a high c/a ratio-that ensures that only basal slip is operative-is a sufficient condition for a solid to be KNE. The c/a ratio of sapphire is 2.73 and thus, if our conjecture is correct, it should be a KNE solid. Herein by repeatedly loading-up to 30 times-the same location of sapphire single crystals of two orientations-A and C-with a 1 μm radius spherical nanoindenter, followed by atomic force microscopy, we showed that sapphire is indeed a KNE solid. After pop-ins of the order of 100 nm, the repeated loadings give rise to fully reversible, reproducible hysteresis loops wherein the energy dissipated per unit volume per cycle Wd is of the order of 0.5 GJ/m3. Wd is due to the back and fro motion of the dislocations making up the incipient kink bands that are fully reversible. The results presented here strongly suggest that-like in graphite and mica-kink bands play a more critical role in the room temperature constrained deformation of sapphire than had hitherto been appreciated. Our interpretation is also in agreement with, and can explain most, recent nanoindentation results on sapphire.

  8. Intracavity doubling of CW Ti:sapphire laser to 392.5 nm using BiBO-crystal

    DEFF Research Database (Denmark)

    Mortensen, Jesper Liltorp; Thorhauge, Morten; Tidemand-Lichtenberg, Peter

    2005-01-01

    In this work we present results obtained for intra-cavity frequency-doubling of a 785 nm CW Ti:sapphire laser utilising BiBO as the non-linear crystal. Intracavity doubling offers several advantages compared to extra-cavity doubling, such as no need to couple to an external resonance cavity...

  9. Structural properties, crystal quality and growth modes of MOCVD-grown AlN with TMAl pretreatment of sapphire substrate

    KAUST Repository

    Sun, Haiding; Wu, Feng; Altahtamouni, Talal Mohammed Ahmad; Alfaraj, Nasir; Li, Kun; Detchprohm, Theeradetch; Dupuis, Russell; Li, Xiaohang

    2017-01-01

    The growth of high quality AlN epitaxial films relies on precise control of the initial growth stages. In this work, we examined the influence of the trimethylaluminum (TMAl) pretreatment of sapphire substrates on the structural properties, crystal quality and growth modes of heteroepitaxial AlN films on (0001) sapphire substrates. Without the pretreatment, the AlN films nucleated on the smooth surface but exhibited mixed crystallographic Al- (N-) polarity, resulting in rough AlN film surfaces. With increasing the pretreatment time from 1 to 5 s, the N-polarity started to be impeded. However, small islands were formed on sapphire surface due to the decompostion of TMAl. As a result, small voids became noticeable at the nucleation layer (NL) because the growth started as quasi three-dimensional (3D) but transformed to 2D mode as the film grew thicker and got coalesced, leading to smoother and Al-polar films. On the other hand, longer pretreatment time of 40 s formed large 3D islands on sapphire, and thus initiated a 3D-growth mode of the AlN film, generating Al-polar AlN nanocolumns with different facets, which resulted into rougher film surfaces. The epitaxial growth modes and their correlation with the AlN film crystal quality under different TMAl pretreatments are also discussed.

  10. Structural properties, crystal quality and growth modes of MOCVD-grown AlN with TMAl pretreatment of sapphire substrate

    KAUST Repository

    Sun, Haiding

    2017-08-08

    The growth of high quality AlN epitaxial films relies on precise control of the initial growth stages. In this work, we examined the influence of the trimethylaluminum (TMAl) pretreatment of sapphire substrates on the structural properties, crystal quality and growth modes of heteroepitaxial AlN films on (0001) sapphire substrates. Without the pretreatment, the AlN films nucleated on the smooth surface but exhibited mixed crystallographic Al- (N-) polarity, resulting in rough AlN film surfaces. With increasing the pretreatment time from 1 to 5 s, the N-polarity started to be impeded. However, small islands were formed on sapphire surface due to the decompostion of TMAl. As a result, small voids became noticeable at the nucleation layer (NL) because the growth started as quasi three-dimensional (3D) but transformed to 2D mode as the film grew thicker and got coalesced, leading to smoother and Al-polar films. On the other hand, longer pretreatment time of 40 s formed large 3D islands on sapphire, and thus initiated a 3D-growth mode of the AlN film, generating Al-polar AlN nanocolumns with different facets, which resulted into rougher film surfaces. The epitaxial growth modes and their correlation with the AlN film crystal quality under different TMAl pretreatments are also discussed.

  11. Microstructural, optical and electrical properties of Cl-doped CdTe single crystals

    Directory of Open Access Journals (Sweden)

    Choi Hyojeong

    2016-09-01

    Full Text Available Microstructural, optical and electrical properties of Cl-doped CdTe crystals grown by the low pressure Bridgman (LPB method were investigated for four different doping concentrations (unintentionally doped, 4.97 × 1019 cm−3, 9.94 × 1019 cm−3 and 1.99 × 1020 cm−3 and three different locations within the ingots (namely, samples from top, middle and bottom positions in the order of the distance from the tip of the ingot. It was shown that Cl dopant suppressed the unwanted secondary (5 1 1 crystalline orientation. Also, the average size and surface coverage of Te inclusions decreased with an increase in Cl doping concentration. Spectroscopic ellipsometry measurements showed that the optical quality of the Cl-doped CdTe single crystals was enhanced. The resistivity of the CdTe sample doped with Cl at the 1.99 × 1020 cm−3 was above 1010 Ω.cm.

  12. Unidirectional growth and characterization of L-arginine monohydrochloride monohydrate single crystals

    International Nuclear Information System (INIS)

    Sangeetha, K.; Babu, R. Ramesh; Bhagavannarayana, G.; Ramamurthi, K.

    2011-01-01

    Highlights: → L-Arginine monohydrochloride monohydrate (LAHCl) single crystal was grown successfully by unidirectional solution growth method for the first time. → High crystalline perfection was observed for UDS grown crystal compared to CS grown crystal. → The optical transparency and mechanical stability are high for UDS grown LAHCl single crystal. → Optical birefringence measurement on this material. → The piezoelectric resonance frequencies observation - first time observation on this material. - Abstract: L-Arginine monohydrochloride monohydrate (LAHCl) single crystals were grown successfully by conventional and unidirectional solution growth methods. The crystalline perfection of grown crystals was analyzed by high-resolution X-ray diffraction. The linear optical transmittance, mechanical stability of conventional and unidirectional grown LAHCl single crystals were analyzed and compared along (0 0 1) plane. The refractive index and birefringence of LAHCl single crystals were also measured using He-Ne laser source. From the dielectric studies, piezoelectric resonance frequencies were observed in kHz frequency range for both conventional and unidirectional grown LAHCl single crystals along (0 0 1) plane.

  13. Growth, optical, electrical and photoconductivity studies of a novel nonlinear optical single crystal: Mercury cadmium chloride thiocyanate

    Science.gov (United States)

    Kumar, S. M. Ravi; Selvakumar, S.; Sagayaraj, P.; Anbarasi, A.

    2015-02-01

    SCN- ligand based organometallic non-linear optical mercury cadmium chloride thiocyanate (MCCTC) crystals are grown from water plus methanol mixed solvent by slow evaporation technique. The grown crystals are confirmed by single crystal X-ray diffraction analysis which reveals that the MCCTC belongs to rhombohedral system with R3c space group. MCCTC exhibits a SHG efficiency which is nearly 17 times more than that of KDP. The dielectric constant, dielectric loss measurements of the sample have been carried out for different frequencies (100 Hz to 5 MHz) and, temperatures (308 to 388 K) and the results are discussed. Photoconductivity study confirms that the title compound possesses negative photoconducting nature. The surface morphology of MCCTC was also investigated

  14. Antiphase inversion domains in lithium cobaltite thin films deposited on single-crystal sapphire substrates

    International Nuclear Information System (INIS)

    Zheng, S.J.; Fisher, C.A.J.; Hitosugi, T.; Kumatani, A.; Shiraki, S.; Ikuhara, Y.H.; Kuwabara, A.; Moriwake, H.; Oki, H.; Ikuhara, Y.

    2013-01-01

    Antiphase inversion domains in LiCoO 2 thin films prepared by pulsed laser deposition on sapphire single-crystal substrates are analyzed using a combination of (scanning) transmission electron microscopy and first-principles calculations. Domains form epitaxially on the substrates with orientation relationships of [112 ¯ 0] LiCoO 2 (0001) LiCoO 2 //[11 ¯ 00] α-Al 2 O 3 (0001) α-Al 2 O 3 and [1 ¯ 1 ¯ 20] LiCoO 2 (0001) LiCoO 2 //[11 ¯ 00] α-Al 2 O 3 (0001) α-Al 2 O 3 . In addition, substrate/film interfaces with the above orientation relationships always have the same stacking sequence of Al–O–Co–O–Li–O. This is confirmed to be the most energetically stable stacking arrangement according to first-principles calculations. Individual domains form as a result of steps one (0 0 0 1) O–Al–O spacing in height on the otherwise flat substrate surface. Because the orientation of adjacent (0 0 0 1) AlO 6 octahedra in Al 2 O 3 are rotated by 180°, while LiO 6 and CoO 6 octahedra in LiCoO 2 are all aligned in the same direction, substrate steps produce LiCoO 2 domains rotated 180° relative to their neighbors. The similar size of oxygen octahedra in the two materials also means that the step height is close to the layer spacing in LiCoO 2 , so that (0 0 0 1) Li and Co layers of adjacent domains are shifted by one layer relative to each other at each domain boundary, aligning Li layers with Co layers across the boundary. The combination of these two effects generates antiphase inversion domains. The domain boundaries effectively sever Li-ion diffusion pathways in the (0 0 0 1) planes between domains and thus are expected to have a detrimental effect on Li-ion conductivity

  15. Optical properties tailoring by high fluence implantation of Ag ions on sapphire

    International Nuclear Information System (INIS)

    Marques, C.; Silva, R.C. da; Wemans, A.; Maneira, M.J.P.; Kozanecki, A.; Alves, E.

    2006-01-01

    Optical and structural properties of single crystalline α-Al 2 O 3 were changed by the implantation of high fluences of Ag ions. Colourless transparent (101-bar 0) sapphire samples were implanted at room temperature with 160keV silver ions and fluences up to 1x10 17 Agcm -2 . Surface amorphization is observed at the fluence of 6x10 16 Agcm -2 . Except for the lower fluences (below 6x10 16 Agcm -2 ) the optical absorption spectra reveal the presence of a band peaking in the region 450-500nm, depending on the retained fluence. This band has been attributed to the presence of silver colloids, being thus 1x10 16 Agcm -2 below the threshold for colloid formation during the implantation. Annealing in oxidizing atmosphere promotes the recrystallization along with segregation of Ag followed by loss through evaporation. Recrystallization is retarded for annealing in reducing atmosphere and the Ag profile displays now a double peak structure after evaporation. Playing with the implantation fluence, temperature and annealing atmosphere controllable shifts of the position and intensity of the optical bands in the visible were achieved

  16. Near surface mechanical properties of optical single crystals and surface response to deterministic microgrinding

    Science.gov (United States)

    Randi, Joseph A., III

    2005-12-01

    This thesis makes use of microindentation, nanoindentation and nanoscratching methods to better understand the mechanical properties of single crystalline silicon, calcium fluoride, and magnesium fluoride. These properties are measured and are used to predict the material's response to material removal, specifically by grinding and polishing, which is a combination of elastic, plastic and fracture processes. The hardness anisotropy during Knoop microindentation, hardness from nanoindentation, and scratch morphology from nanoscratching are reported. This information is related to the surface microroughness from grinding. We show that mechanical property relationships that predict the surface roughness from lapping and deterministic microgrinding of optical glasses are applicable to single crystals. We show the range of hardness from some of the more common crystallographic faces. Magnesium fluoride, having a tetragonal structure, has 2-fold hardness anisotropy. Nanoindentation, as expected provides higher hardness than microindentation, but anisotropy is not observed. Nanoscratching provides the scratch profile during loading, after the load has been removed, and the coefficient of friction during the loading. Ductile and brittle mode scratching is present with brittle mode cracking being orientation specific. Subsurface damage (SSD) measurements are made using a novel process known as the MRF technique. Magnetorheological finishing is used to polish spots into the ground surface where SSD can be viewed. SSD is measured using an optical microscope and knowledge of the spot profile. This technique is calibrated with a previous technique and implemented to accurately measure SSD in single crystals. The data collected are compared to the surface microroughness of the ground surface, resulting in an upper bound relationship. The results indicate that SSD is always less than 1.4 times the peak-to-valley surface microroughness for single crystals regardless of the

  17. Optical characterization of single-crystal diamond grown by DC arc plasma jet CVD

    Science.gov (United States)

    Hei, Li-fu; Zhao, Yun; Wei, Jun-jun; Liu, Jin-long; Li, Cheng-ming; Lü, Fan-xiu

    2017-12-01

    Optical centers of single-crystal diamond grown by DC arc plasma jet chemical vapor deposition (CVD) were examined using a low-temperature photoluminescence (PL) technique. The results show that most of the nitrogen-vacancy (NV) complexes are present as NV- centers, although some H2 and H3 centers and B-aggregates are also present in the single-crystal diamond because of nitrogen aggregation resulting from high N2 incorporation and the high mobility of vacancies under growth temperatures of 950-1000°C. Furthermore, emissions of radiation-induced defects were also detected at 389, 467.5, 550, and 588.6 nm in the PL spectra. The reason for the formation of these radiation-induced defects is not clear. Although a Ni-based alloy was used during the diamond growth, Ni-related emissions were not detected in the PL spectra. In addition, the silicon-vacancy (Si-V)-related emission line at 737 nm, which has been observed in the spectra of many previously reported microwave plasma chemical vapor deposition (MPCVD) synthetic diamonds, was absent in the PL spectra of the single-crystal diamond prepared in this work. The high density of NV- centers, along with the absence of Ni-related defects and Si-V centers, makes the single-crystal diamond grown by DC arc plasma jet CVD a promising material for applications in quantum computing.

  18. EPR and optical absorption studies of VO2+ doped L-alanine (C3H7NO2) single crystals

    International Nuclear Information System (INIS)

    Biyik, Recep

    2009-01-01

    VO 2+ doped L-alanine (C 3 H 7 NO 2 ) single crystals and powders are examined by electron paramagnetic resonance (EPR) and optical absorption spectroscopy. Three magnetically different sites are resolved from angular variations of L-alanine single crystal EPR spectra. In some specific orientations each VO 2+ line splits into three superhyperfine lines with intensities of 1:2:1 and maximum splitting value of 2.23 mT. The local symmetries of VO 2+ complex sites are nearly axial. The optical absorption spectra show three bands. Spin Hamiltonian parameters are measured and molecular orbital coefficients are calculated by correlating EPR and optical absorption data for the central vanadyl ion.

  19. Frequency-doubled DBR-tapered diode laser for direct pumping of Ti:sapphire lasers generating sub-20 fs pulses

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2011-01-01

    For the first time a single-pass frequency doubled DBR-tapered diode laser suitable for pumping Ti:sapphire lasers generating ultrashort pulses is demonstrated. The maximum output powers achieved when pumping the Ti:sapphire laser are 110 mW (CW) and 82 mW (mode-locked) respectively at 1.2 W...... of pump power. This corresponds to a reduction in optical conversion efficiencies to 75% of the values achieved with a commercial diode pumped solid-state laser. However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2....... The optical spectrum emitted by the Ti:sapphire laser when pumped with our diode laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20 fs can therefore be expected....

  20. Frequency-doubled DBR-tapered diode laser for direct pumping of Ti:sapphire lasers generating sub-20 fs pulses.

    Science.gov (United States)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika; Le, Tuan; Stingl, Andreas; Hasler, Karl-Heinz; Sumpf, Bernd; Erbert, Götz; Andersen, Peter E; Petersen, Paul Michael

    2011-06-20

    For the first time a single-pass frequency doubled DBR-tapered diode laser suitable for pumping Ti:sapphire lasers generating ultrashort pulses is demonstrated. The maximum output powers achieved when pumping the Ti:sapphire laser are 110 mW (CW) and 82 mW (mode-locked) respectively at 1.2 W of pump power. This corresponds to a reduction in optical conversion efficiencies to 75% of the values achieved with a commercial diode pumped solid-state laser. However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser when pumped with our diode laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20 fs can therefore be expected.

  1. Growth and dielectric, mechanical, thermal and etching studies of an organic nonlinear optical L-arginine trifluoroacetate (LATF) single crystal

    International Nuclear Information System (INIS)

    Arjunan, S.; Mohan Kumar, R.; Mohan, R.; Jayavel, R.

    2008-01-01

    L-arginine trifluoroacetate, an organic nonlinear optical material, has been synthesized from aqueous solution. Bulk single crystal of dimension 57 mm x 5 mm x 3 mm has been grown by temperature lowering technique. Powder X-ray diffraction studies confirmed the monoclinic structure of the grown L-arginine trifluoroacetate crystal. Linear optical property of the grown crystal has been studied by UV-vis spectrum. Dielectric response of the L-arginine trifluoroacetate crystal was analysed for different frequencies and temperatures in detail. Microhardness study on the sample reveals that the crystal possesses relatively higher hardness compared to many organic crystals. Thermal analyses confirmed that the L-arginine trifluoroacetate material is thermally stable upto 212 deg. C. The etching studies have been performed to assess the perfection of the L-arginine trifluoroacetate crystal. Kurtz powder second harmonic generation test confirms the nonlinear optical properties of the as-grown L-arginine trifluoroacetate crystal

  2. Crystal structure, growth and nonlinear optical studies of isonicotinamide p-nitrophenol: A new organic crystal for optical limiting applications

    Science.gov (United States)

    Vijayalakshmi, A.; Vidyavathy, B.; Vinitha, G.

    2016-08-01

    Isonicotinamide p-nitrophenol (ICPNP), a new organic material, was synthesized using methanol solvent. Single crystals of ICPNP were grown using a slow evaporation solution growth technique. Crystal structure of ICPNP is elucidated by single crystal X-ray diffraction analysis. It belongs to monoclinic crystal system with space group of P21/c. It forms two dimensional networks by O-H…O, N-H…O and C-H…O hydrogen bonds. The molecular structure of ICPNP was further confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical transmittance range and the lower cut-off wavelength (421 nm) with the optical band gap (2.90 eV) of the ICPNP crystal were determined by UV-vis-NIR spectral study. Thermal behavior of ICPNP was studied by thermo gravimetric and differential thermal analyses (TG/DTA). The relative dielectric permittivity was calculated for various temperature ranges. Laser damage threshold of ICPNP crystal was found to be 1.9 GW/cm2 using an Nd:YAG laser. A Z-scan technique was employed to measure the nonlinear absorption coefficient, nonlinear refractive index and nonlinear optical susceptibility. Optical limiting behavior of ICPNP was observed at 35 mW input power.

  3. Using a novel spectroscopic reflectometer to optimize a radiation-hardened submicron silicon-on-sapphire CMOS process

    International Nuclear Information System (INIS)

    Do, N.T.; Zawaideh, E.; Vu, T.Q.; Warren, G.; Mead, D.; Do, N.T.; Li, G.P.; Tsai, C.S.

    1999-01-01

    A radiation-hardened sub-micron silicon-on-sapphire CMOS process is monitored and optimized using a novel optical technique based on spectroscopic reflectometry. Quantitative measurements of the crystal quality, surface roughness, and device radiation hardness show excellent correlation between this technique and the Atomic Force Microscopy. (authors)

  4. The effect of a slight mis-orientation angle of c-plane sapphire substrate on surface and crystal quality of MOCVD grown GaN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong-Woo; Suzuki, Toshimasa [Nippon Institute of Technology, 4-1 Gakuendai, Miyashiro, Saitama, 345-8501 (Japan); Aida, Hideo [NAMIKI Precision Jewel Co. Ltd., 3-8-22 Shinden, Adachi-ku, Tokyo, 123-8511 (Japan)

    2004-09-01

    The effect of a slight mis-orientation of c-plane sapphire substrate on the surface morphology and crystal quality of GaN thin films grown by MOCVD has been investigated. The mis-orientation angle of vicinal c-plane sapphire substrate was changed within the range of 0.00(zero)-1.00(one) degree, and the experimental results were compared with those on just angle (zero degree) c-plane sapphire substrate. The surface morphology and crystal quality were found to be very sensitive to mis-orientation angle. Consequently, the mis-orientation angle was optimized to be 0.15 . (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Optical and scintillating properties of Ce:Li(Y,Lu)F4 single crystals

    International Nuclear Information System (INIS)

    Yokota, Yuui; Kurosawa, Shunsuke; Chani, Valery; Kamada, Kei; Yoshikawa, Akira

    2014-01-01

    We have investigated the optical and scintillating properties of Lu co-doped Ce:LiYF 4 single crystals with various Lu content. In the transmittance and absorption spectra, the absorption peaks at 243 nm get systematically red shifted in contrast to the peaks at 197 and 200 nm which get blue shifted with the increase in Lu content. At the same time, emission peaks at 306 nm and 200 nm under 295 nm excitation also get red shifted. The decay time of Ce:Li(Y,Lu)F 4 crystals under 295 nm excitation is found to be faster than that of Ce:LiYF 4 and Ce:LiLuF 4 crystals. The alpha-peak positions in the pulse-height spectra and decay times of crystals under alpha-ray irradiation are found to vary with the Lu content. - Highlights: • Optical and scintillation properties of Ce:Li(Y 1-x Lu x )F 4 crystals were inspected. • Increase of Lu content resulted change of the position of four absorption peaks. • Admixing of Y and Lu decreased the light yield and increased the decay time. • The Ce:LiLuF 4 crystal indicated the largest light yield in the pulse-height spectra. • Li[(Y 0.8 Lu 0.2 ) 0.98 Ce 0.02 ]F 4 indicated larger light yield than Ce:LiYF 4 crystal

  6. Investigations on nucleation, HRXRD, optical, piezoelectric, polarizability and Z-scan analysis of L-arginine maleate dihydrate single crystals

    Science.gov (United States)

    Sakthy Priya, S.; Alexandar, A.; Surendran, P.; Lakshmanan, A.; Rameshkumar, P.; Sagayaraj, P.

    2017-04-01

    An efficient organic nonlinear optical single crystal of L-arginine maleate dihydrate (LAMD) has been grown by slow evaporation solution technique (SEST) and slow cooling technique (SCT). The crystalline perfection of the crystal was examined using high-resolution X-ray diffractometry (HRXRD) analysis. Photoluminescence study confirmed the optical properties and defects level in the crystal lattice. Electromechanical behaviour was observed using piezoelectric co-efficient (d33) analysis. The photoconductivity analysis confirmed the negative photoconducting nature of the material. The dielectric constant and loss were measured as a function of frequency with varying temperature and vice-versa. The laser damage threshold (LDT) measurement was carried out using Nd:YAG Laser with a wavelength of 1064 nm (Focal length is 35 cm) and the obtained results showed that LDT value of the crystal is high compared to KDP crystal. The high laser damage threshold of the grown crystal makes it a potential candidate for second and higher order nonlinear optical device application. The third order nonlinear optical parameters of LAMD crystal is determined by open-aperture and closed-aperture studies using Z-scan technique. The third order linear and nonlinear optical parameters such as the nonlinear refractive index (n2), two photon absorption coefficient (β), Real part (Reχ3) and imaginary part (Imχ3) of third-order nonlinear optical susceptibility are calculated.

  7. Investigation on the growth, spectral, lifetime, mechanical analysis and third-order nonlinear optical studies of L-methionine admixtured D-mandelic acid single crystal: A promising material for nonlinear optical applications

    Science.gov (United States)

    Jayaprakash, P.; Sangeetha, P.; Kumari, C. Rathika Thaya; Caroline, M. Lydia

    2017-08-01

    A nonlinear optical bulk single crystal of L-methionine admixtured D-mandelic acid (LMDMA) has been grown by slow solvent evaporation technique using water as solvent at ambient temperature. The crystallized LMDMA single crystal subjected to single crystal X-ray diffraction study confirmed monoclinic system with the acentric space group P21. The FTIR analysis gives information about the modes of vibration in the various functional groups present in LMDMA. The UV-visible spectral analysis assessed the optical quality and linear optical properties such as extinction coefficient, reflectance, refractive index and from which optical conductivity and electric susceptibility were also evaluated. The frequency doubling efficiency was observed using Kurtz Perry powder technique. A multiple shot laser was utilized to evaluate the laser damage threshold energy of the crystal. Discrete thermodynamic properties were carried out by TG-DTA studies. The hardness, Meyer's index, yield strength, elastic stiffness constant, Knoop hardness, fracture toughness and brittleness index were analyzed using Vickers microhardness tester. Layer growth pattern and the surface defect were examined by chemical etching studies using optical microscope. Fluorescence emission spectrum was recorded and lifetime was also studied. The electric field response of crystal was investigated from the dielectric studies at various temperatures at different frequencies. The third-order nonlinear optical response in LMDMA has been investigated using Z-scan technique with He-Ne laser at 632.8 nm and nonlinear parameters such as refractive index (n2), absorption coefficient (β) and susceptibility (χ3) investigated extensively for they are in optical phase conjucation, high-speed optical switches and optical dielectric devices.

  8. Twisted intra-molecular charge transfer investigations of semiorganic triglycine phosphate single crystal for non linear optical applications

    Science.gov (United States)

    Meera, M. R.; Joselin Beaula, T.; Rayar, S. L.; Bena Jothy, V.

    2017-09-01

    NLO materials are gaining importance in technologies such as optical communication, optical computing and dynamic image processing. Many NLO crystals grown by mixing amino acids with various organic and inorganic acids have been reported in the literature. Hence, glycine mixed semi-organic material will be of special interest as a fundamental building block to develop many complex crystals with improved NLO properties. A semi organic Single crystal of Triglycine Phosphate (TGP) which was grown and spectral analysis have been using FTIR and Raman spectral analysis. Natural Bond Orbital Analysis and the atomic natural charges are also predicted. HOMO LUMO energy gap value suggests the possibility of charge transfer within the molecule.

  9. Non linear optical studies on semiorganic single crystal: L-arginine 4-nitrophenalate 4-nitrophenol dihydrate (LAPP)

    Science.gov (United States)

    Mahadevan, M.; Sankar, P. K.; Vinitha, G.; Arivanandhan, M.; Ramachandran, K.; Anandan, P.

    2017-07-01

    L-arginine 4-nitrophenalate 4-nitrophenol dihydrate (LAPP) has been synthesized and grown by solution growth at room temperature using deionized water as a solvent. The various functional groups of the sample were identified by Fourier transform infra-red and Fourier transforms - Raman spectroscopic analyses. The Laser damage threshold of LAPP has been studied. Refractive index of LAPP single crystal was measured using Metricon prism coupler Instrument. The etching studies were carried out to study the quality of the grown crystals. The third order nonlinear optical properties of LAPP sample was analyzed by the Z-scan technique using 532 nm diode pumped CW Nd: YAG laser. The LAPP material exhibits negative optical nonlinearity. The results show that LAPP sample has potential applications in nonlinear optics and it can be exploited for optical limiting or switching.

  10. A quantum optical transistor with a single quantum dot in a photonic crystal nanocavity

    International Nuclear Information System (INIS)

    Li Jinjin; Zhu Kadi

    2011-01-01

    Laser and strong coupling can coexist in a single quantum dot (QD) coupled to a photonic crystal nanocavity. This provides an important clue towards the realization of a quantum optical transistor. Using experimentally realistic parameters, in this work, theoretical analysis shows that such a quantum optical transistor can be switched on or off by turning on or off the pump laser, which corresponds to attenuation or amplification of the probe laser, respectively. Furthermore, based on this quantum optical transistor, an all-optical measurement of the vacuum Rabi splitting is also presented. The idea of associating a quantum optical transistor with this coupled QD-nanocavity system may achieve images of light controlling light in all-optical logic circuits and quantum computers.

  11. A quantum optical transistor with a single quantum dot in a photonic crystal nanocavity.

    Science.gov (United States)

    Li, Jin-Jin; Zhu, Ka-Di

    2011-02-04

    Laser and strong coupling can coexist in a single quantum dot (QD) coupled to a photonic crystal nanocavity. This provides an important clue towards the realization of a quantum optical transistor. Using experimentally realistic parameters, in this work, theoretical analysis shows that such a quantum optical transistor can be switched on or off by turning on or off the pump laser, which corresponds to attenuation or amplification of the probe laser, respectively. Furthermore, based on this quantum optical transistor, an all-optical measurement of the vacuum Rabi splitting is also presented. The idea of associating a quantum optical transistor with this coupled QD-nanocavity system may achieve images of light controlling light in all-optical logic circuits and quantum computers.

  12. Reliability improvement methods for sapphire fiber temperature sensors

    Science.gov (United States)

    Schietinger, C.; Adams, B.

    1991-08-01

    Mechanical, optical, electrical, and software design improvements can be brought to bear in the enhancement of fiber-optic sapphire-fiber temperature measurement tool reliability in harsh environments. The optical fiber thermometry (OFT) equipment discussed is used in numerous process industries and generally involves a sapphire sensor, an optical transmission cable, and a microprocessor-based signal analyzer. OFT technology incorporating sensors for corrosive environments, hybrid sensors, and two-wavelength measurements, are discussed.

  13. Synthesis, optical, experimental and theoretical investigation of third order nonlinear optical properties of 8-hydroxyquinolinium 2-carboxy-6-nitrophthalate monohydrate single crystal

    Science.gov (United States)

    Bharathi, M. Divya; Bhuvaneswari, R.; Srividya, J.; Vinitha, G.; Prithiviraajan, R. N.; Anbalagan, G.

    2018-02-01

    Single crystals of 8-hydroxyquinolinium 2-carboxy-6-nitrophthalate monohydrate (8HQNP) were obtained from slow evaporation solution growth method using methanol-water (1:1) as a solvent. Powder X-ray diffraction was utilized to compute the unit cell parameters and dislocation density of 8HQNP crystal. The crystalline perfection of the as-grown crystal was investigated by high-resolution X-ray diffraction at room temperature. The molecular structure was analyzed by identifying the functional groups from FT-IR and FT-Raman spectra. The cut-off wavelength and the corresponding optical band gap obtained from an optical spectrum were 376 nm and 3.29 eV respectively. The dispersion nature of refractive index was investigated by the single-oscillator Wemple and Di-Domenico model. Red emission was observed in the photoluminescence spectrum when excited with 376 nm. The low birefringence and high laser damage threshold (8.538 GW/cm2) values dictate the suitability of the crystal for optical devices. Z-scan studies revealed the third order nonlinear absorption coefficient (β) and refractive index (n2) of the 8HQNP crystal. The theoretical value of third order nonlinear susceptibility obtained from density function theory is good accordance with the experimental value. The frontier molecular orbital energy gap decreases with increasing external electric field in different directions which attributed to the enhancement of the second hyperpolarizability. The grown title crystal is thermally stable up to 102 °C which was identified using thermal analysis. Mechanical strength of 8HQNP was estimated by using Vicker's microhardness studies.

  14. Single crystal growth, electronic structure and optical properties of Cs2HgBr4

    Science.gov (United States)

    Lavrentyev, A. A.; Gabrelian, B. V.; Vu, V. T.; Shkumat, P. N.; Parasyuk, O. V.; Fedorchuk, A. O.; Khyzhun, O. Y.

    2015-10-01

    We report on successful synthesis of high-quality single crystal of cesium mercury tetrabromide, Cs2HgBr4, by using the vertical Bridgman-Stockbarger method as well as on studies of its electronic structure. For the Cs2HgBr4 crystal, we have recorded X-ray photoelectron spectra for both pristine and Ar+ ion-bombarded surfaces. Our data indicate that the Cs2HgBr4 single crystal surface is rather sensitive with respect to Ar+ ion-bombardment. In particular, such a treatment of the Cs2HgBr4 single crystal surface alters its elemental stoichiometry. To explore peculiarities of the energy distribution of total and partial densities of states within the valence band and the conduction band of Cs2HgBr4, we have made band-structure calculations based on density functional theory (DFT) employing the augmented plane wave+local orbitals (APW+lo) method as incorporated in the WIEN2k package. The APW+lo calculations allow for concluding that the Br 4p states make the major contributions in the upper portion of the valence band, while its lower portion is dominated by contributors of the Hg 5d and Cs 5p states. Further, the main contributors to the bottom of the conduction band of Cs2HgBr4 are the unoccupied Br p and Hg s states. In addition, main optical characteristics of Cs2HgBr4 such as dispersion of the absorption coefficient, real and imaginary parts of dielectric function, electron energy-loss spectrum, refractive index, extinction coefficient and optical reflectivity have been explored from the first-principles band-structure calculations.

  15. Multifunctional Bi2ZnOB2O6 single crystals for second and third order nonlinear optical applications

    International Nuclear Information System (INIS)

    Iliopoulos, K.; Kasprowicz, D.; Majchrowski, A.; Michalski, E.; Gindre, D.; Sahraoui, B.

    2013-01-01

    Bi 2 ZnOB 2 O 6 nonlinear optical single crystals were grown by means of the Kyropoulos method from stoichiometric melt. The second and third harmonic generation (SHG/THG) of Bi 2 ZnOB 2 O 6 crystals were investigated by the SHG/THG Maker fringes technique. Moreover, SHG microscopy studies were carried out providing two-dimensional SHG images as a function of the incident laser polarization. The high nonlinear optical efficiency combined with the possibility to grow high quality crystals make Bi 2 ZnOB 2 O 6 an excellent candidate for photonic applications

  16. Electric-field gradient characterization at {sup 181}Ta impurities in sapphire single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Renteria, M.; Darriba, G.N.; Errico, L.A.; Munoz, E.L. [Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC 67, 1900 La Plata (Argentina); Eversheim, P.D. [Helmholtz-Institut fuer Strahlen-und Kernphysik (ISKP), Universitaet Bonn, Nussallee 14-16, 53115 Bonn (Germany)

    2005-07-01

    We report Perturbed-Angular-Correlation (PAC) experiments on corundum Al{sub 2}O{sub 3} single crystals implanted with {sup 181}Hf/{sup 181}Ta ions at the ISKP at Bonn and measured at La Plata with high efficiency and time-resolution. The magnitude, asymmetry, and orientation (with respect to the crystalline axes) of the electric-field gradient (EFG) tensor were determined measuring the spin-rotation curves as a function of different orientations of the single crystals relative to the detector system. These results are analyzed in the framework of point-charge model and ab initio Full-Potential Linearized-Augmented Plane Wave calculations, and compared with EFG results coming from PAC experiments with {sup 111}In/{sup 111}Cd impurities. This combined study enables the determination of lattice relaxations induced by the presence of the impurity and the state of charge of a deep impurity donor level in the band gap of the semiconductor. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Growth and characterization of dichlorobis L-proline Zn(II): A semiorganic nonlinear optical single crystal

    Science.gov (United States)

    Lydia Caroline, M.; Kandasamy, A.; Mohan, R.; Vasudevan, S.

    2009-02-01

    A semiorganic nonlinear optical material dichlorobis L-proline Zn (II) (DBLPZ), with molecular formula [ZnCl 2(C 5H 9NO 2) 2], has been synthesized from mixed solvents of deionised water and methanol. Single crystals of DBLPZ were successfully grown by the slow evaporation method at an ambient temperature. Single-crystal X-ray diffractometer was utilized to measure unit cell parameters and to confirm the crystal structure. The powder X-ray diffraction pattern of the grown DBLPZ has been indexed. The modes of vibration of different molecular groups present in the sample were identified by the FTIR spectral analysis. The optical transmittance window and the lower cutoff wavelength of the DBLPZ have been identified by UV-vis-NIR studies. Thermal stability of the DBLPZ was determined from TG/DTA/DSC curves, which indicate that the material is stable up to 242.3 °C. The existence of second harmonic generation signals was observed using Nd:YAG laser with fundamental wavelength of 1064 nm possessing SHG efficiency of 0.5 times of KDP and hence it can be a potential material for the frequency-doubling process.

  18. Study of thermochemically reduced and electron-irradiated LiNbO3 single crystals by positron annihilation and optical absorption measurements

    International Nuclear Information System (INIS)

    Pareja, R.; Gonzalez, R.; Pedrosa, M.A.

    1984-01-01

    Irradiation of LiNbO 3 single crystals using Van de Graaff electrons with an energy of 1.5 MeV introduces an optical absorption band similar to that observed in thermochemically reduced samples. As-grown, reduced, or irradiated crystals show single-component positron lifetime spectra with an average decay time of 234 ps. (author)

  19. Magnetic, transport, and optical properties of Ca0.85Eu0.15MnO3 single crystal

    International Nuclear Information System (INIS)

    Naumov, S.V.; Loshkareva, N.N.; Mostovshchikova, E.V.; Solin, N.I.; Korolev, A.V.; Arbuzova, T.I.; Telegin, S.V.; Patrakov, E.I.

    2013-01-01

    Magnetic, transport and optical properties of the Ca 0.85 Eu 0.15 MnO 3 single crystal are studied and discussed in comparison with the properties of polycrystalline sample. The magnetic data show existence the two magnetic phase transitions under cooling: the transition near 150 K occurs from the paramagnetic orthorhombic to C-type antiferromagnetic monoclinic phase with the charge/orbital ordering in some part of the crystal; and at 90 K the transition from the paramagnetic to G-type antiferromagnetic phase takes place in another part of the crystal with the orthorhombic structure. The magnetoresistance of the Ca 0.85 Eu 0.15 MnO 3 single crystal has features at temperatures of these phase transitions. Differences in the properties of single crystal and polycrystalline sample with the same content of Eu are associated with the ordering of oxygen vacancies that appear under the crystal growth. The reflection spectra in infrared range confirm the existence of the electron conductivity in a narrow band at room temperature.

  20. Nonlinear and quantum optics with liquid crystals

    International Nuclear Information System (INIS)

    Lukishova, Svetlana G

    2014-01-01

    Thermotropic liquid crystals' usual application is display technology. This paper describes experiments on light interaction with pure and doped liquid crystals under for these materials unconventional incident light powers: (1) under high-power laser irradiation, and (2) at the single-photon level. In (1), I will outline several nonlinear optical effects under high-power, nanosecond laser irradiation which should be taken into account in the design of lasers with liquid crystal components and in fabrication of optical power limiters based on liquid crystals: (1.1) athermal helical pitch dilation and unwinding of cholesteric mirrors (both in free space and inside laser resonators); (1.2) some pitfalls in measurements of refractive nonlinearity using z-scan technique under two-photon or linear absorption of liquids; (1.3) the first observation of thermal lens effects in liquid crystals under several-nanosecond, low-pulse-repetition rate (2-10 Hz) laser irradiation in the presence of two-photon absorption; (1.4) feedback-free kaleidoscope of patterns (hexagons, stripes, etc.) in dye-doped liquid crystals. In (2), at the single-photon level, it will be shown that with a proper selection of liquid crystals and a single-emitter dopant spectral range, liquid crystal structures can be used to control emitted single photons (both polarization and count rate). The application of the latter research is absolutely secure quantum communication with polarization coding of information. In particular, in (2.1), definite handedness, circular polarized cholesteric microcavity resonance in quantum dot fluorescence is reported. In (2.2), definite linear polarization of single (antibunched) photons from single-dye-molecules in planar-aligned nematic host is discussed. In (2.3), some results on photon antibunching from NV-color center in nanodiamond in liquid crystal host and circularly polarized fluorescence of definite handedness from nanocrystals doped with trivalent ions of

  1. Optical characteristics of Tl0.995Cu0.005InS2 single crystals

    Science.gov (United States)

    El-Nahass, M. M.; Ali, H. A. M.; Abu-Samaha, F. S. H.

    2013-04-01

    Optical properties of Tl0.995Cu0.005InS2 single crystals were studied using transmittance and reflectance measurements in the spectral wavelength range of 300-2500 nm. The optical constants (n and k) were calculated at room temperature. The analysis of the spectral behavior of the absorption coefficient in the absorption region revealed indirect transition. The refractive index dispersion data were analyzed in terms of the single oscillator model. Dispersion parameters such as the single oscillator energy (Eo), the dispersion energy (Ed), the high frequency dielectric constant (ε∞), the lattice dielectric constant (εL) and the ratio of free charge carrier concentration to the effective mass (N/m*) were estimated. The third order nonlinear susceptibility (χ(3)) was calculated according to the generalized Miller's rule. Also, the real and imaginary parts of the complex dielectric constant were determined.

  2. A novel organic nonlinear optical crystal: Creatininium succinate

    Energy Technology Data Exchange (ETDEWEB)

    Thirumurugan, R.; Anitha, K., E-mail: singlecerystalxrd@gmail.ciom [School of Physics, Madurai Kamraj University, Madurai 625021 (India)

    2015-06-24

    A novel organic material complex of creatininium succinate (CS) has been synthesized and single crystals were grown by the reaction of creatinine and succinic acid from aqueous solution by employing the technique of slow evaporation at room temperature. The structure of the grown crystal has been elucidated using single crystal X-ray diffraction analysis and the structure was refined by least-squares method to R = 0.027 for 1840 reflections. FT-IR spectral investigation has been carried out to identify the various functional groups in the title compound. UV–Vis transmission was carried out which shows the crystal has a good optical transmittance in the visible region with lower cutoff wavelength around 220 nm. Nonlinear optical property of the crystal was confirmed by Kurtz-Perry powder technique.

  3. Attenuation of Reactor Gamma Radiation and Fast Neutrons Through Large Single-Crystal Materials

    International Nuclear Information System (INIS)

    Adib, M.

    2009-01-01

    A generalized formula is given which, for neutron energies in the range 10-4< E< 10 eV and gamma rays with average energy 2 MeV , permits calculation of the transmission properties of several single crystal materials important for neutron scattering instrumentation. A computer program Filter was developed which permits the calculation of attenuation of gamma radiation, nuclear capture, thermal diffuse and Bragg-scattering cross-sections as a function of materials constants, temperature and neutron energy. The applicability of the deduced formula along with the code checked from the obtained agreement between the calculated and experimental neutron transmission through various single-crystals A feasibility study for use of Si, Ge, Pb, Bi and sapphire is detailed in terms of optimum crystal thickness, mosaic spread and cutting plane for efficient transmission of thermal reactor neutrons and for rejection of the accompanying fast neutrons and gamma rays.

  4. Theoretical studies on lattice-oriented growth of single-walled carbon nanotubes on sapphire

    Science.gov (United States)

    Li, Zhengwei; Meng, Xianhong; Xiao, Jianliang

    2017-09-01

    Due to their excellent mechanical and electrical properties, single-walled carbon nanotubes (SWNTs) can find broad applications in many areas, such as field-effect transistors, logic circuits, sensors and flexible electronics. High-density, horizontally aligned arrays of SWNTs are essential for high performance electronics. Many experimental studies have demonstrated that chemical vapor deposition growth of nanotubes on crystalline substrates such as sapphire offers a promising route to achieve such dense, perfectly aligned arrays. In this work, a theoretical study is performed to quantitatively understand the van der Waals interactions between SWNTs and sapphire substrates. The energetically preferred alignment directions of SWNTs on A-, R- and M-planes and the random alignment on the C-plane predicted by this study are all in good agreement with experiments. It is also shown that smaller SWNTs have better alignment than larger SWNTs due to their stronger interaction with sapphire substrate. The strong vdW interactions along preferred alignment directions can be intuitively explained by the nanoscale ‘grooves’ formed by atomic lattice structures on the surface of sapphire. This study provides important insights to the controlled growth of nanotubes and potentially other nanomaterials.

  5. Trapezoidal diffraction grating beam splitters in single crystal diamond

    Science.gov (United States)

    Kiss, Marcell; Graziosi, Teodoro; Quack, Niels

    2018-02-01

    Single Crystal Diamond has been recognized as a prime material for optical components in high power applications due to low absorption and high thermal conductivity. However, diamond microstructuring remains challenging. Here, we report on the fabrication and characterization of optical diffraction gratings exhibiting a symmetric trapezoidal profile etched into a single crystal diamond substrate. The optimized grating geometry diffracts the transmitted optical power into precisely defined proportions, performing as an effective beam splitter. We fabricate our gratings in commercially available single crystal CVD diamond plates (2.6mm x 2.6mm x 0.3mm). Using a sputter deposited hard mask and patterning by contact lithography, the diamond is etched in an inductively coupled oxygen plasma with zero platen power. The etch process effectively reveals the characteristic {111} diamond crystal planes, creating a precisely defined angled (54.7°) profile. SEM and AFM measurements of the fabricated gratings evidence the trapezoidal shape with a pitch of 3.82μm, depth of 170 nm and duty cycle of 35.5%. Optical characterization is performed in transmission using a 650nm laser source perpendicular to the sample. The recorded transmitted optical power as function of detector rotation angle shows a distribution of 21.1% in the 0th order and 23.6% in each +/-1st order (16.1% reflected, 16.6% in higher orders). To our knowledge, this is the first demonstration of diffraction gratings with trapezoidal profile in single crystal diamond. The fabrication process will enable beam splitter gratings of custom defined optical power distribution profiles, while antireflection coatings can increase the efficiency.

  6. Studies on the growth aspects, structural, thermal, dielectric and third order nonlinear optical properties of solution grown 4-methylpyridinium p-nitrophenolate single crystal

    Science.gov (United States)

    Devi, S. Reena; Kalaiyarasi, S.; Zahid, I. MD.; Kumar, R. Mohan

    2016-11-01

    An ionic organic optical crystal of 4-methylpyridinium p-nitrophenolate was grown from methanol by slow evaporation method at ambient temperature. Powder and single crystal X-ray diffraction studies revealed the crystal system and its crystalline perfection. The rocking curve recorded from HRXRD study confirmed the crystal quality. FTIR spectral analysis confirmed the functional groups present in the title compound. UV-visible spectral study revealed the optical window and band gap of grown crystal. The thermal, electrical and surface laser damage threshold properties of harvested crystal were examined by using TGA/DTA, LCR/Impedance Analyzer and Nd:YAG laser system respectively. The third order nonlinear optical property of grown crystal was elucidated by Z-scan technique.

  7. Growth and surface topography of WSe_2 single crystal

    International Nuclear Information System (INIS)

    Dixit, Vijay; Vyas, Chirag; Pataniya, Pratik; Jani, Mihir; Pathak, Vishal; Patel, Abhishek; Pathak, V. M.; Patel, K. D.; Solanki, G. K.

    2016-01-01

    Tungsten Di-Selenide belongs to the family of TMDCs showing their potential applications in the fields of Optoelectronics and PEC solar cells. Here in the present investigation single crystals of WSe_2 were grown by Direct Vapour Transport Technique in a dual zone furnace having temperature difference of 50 K between the two zones. These single crystals were characterized by EDAX which confirms the stiochiometry of the grown crystals. Surface topography of the crystal was studied by optical micrograph showing the left handed spirals on the surface of WSe_2 crystals. Single crystalline nature of the crystals was confirmed by SAED.

  8. Growth, structural, thermal, dielectric and nonlinear optical properties of potassium hexachloro cadmate (IV) a novel single crystal

    Science.gov (United States)

    Umarani, P.; Jagannathan, K.

    2018-02-01

    The Potassium hexachloro cadmate (IV) (PHC) single crystal was grown from the aqueous of the solution by a controlled evaporation method. Single crystal XRD solved the structure. FTIR is used to identify the functional groups of grown crystal. The UV-Vis-NIR spectrometer was used to find out the UV cut off region and to calculate the optical band gap of the Potassium hexachloro cadmate (IV) single crystal. The EDAX spectrum has been used to identify the compounds present in title compound. The TG-DTA profile shows the thermal stability of the grown crystal of Potassium hexachloro cadmate (IV). The Vicker's hardness measurement was used to calculate the material hardness of the title compound. The dielectric loss and constant varied with frequencies and activation energy is also calculated. The solid state parameters like plasma energy, Penn gap, Fermi energy, electronic polarizability using Penn analysis and Clausius-Mossotti equation were also calculated for the title compound. The Z-scan technique is used to calculate the third order nonlinear susceptibility of a real and imaginary part.

  9. Oleophobic properties of the step-and-terrace sapphire surface

    Energy Technology Data Exchange (ETDEWEB)

    Muslimov, A. E., E-mail: amuslimov@mail.ru; Butashin, A. V.; Kanevsky, V. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Research Center “Crystallography and Photonics” (Russian Federation)

    2017-03-15

    Sapphire is widely used in production of optical windows for various devices due to its mechanical and optical properties. However, during operation the surface can be affected by fats, oils, and other organic contaminations. Therefore, it is important to improve the oleophobic properties of sapphire windows. In this study, we investigate the interaction of a supersmooth sapphire surface with oleic acid droplets, which imitate human finger printing. It is established that chemical–mechanical polishing with additional annealing in air, which leads to the formation of an atomically smooth sapphire surface, makes it possible to significantly improve the oleophobic properties of the surface. The results are analyzed using the Ventsel–Deryagin homogeneous wetting model.

  10. Growth of optical-quality anthracene crystals doped with dibenzoterrylene for controlled single photon production

    Energy Technology Data Exchange (ETDEWEB)

    Major, Kyle D., E-mail: kyle.major11@imperial.ac.uk; Lien, Yu-Hung; Polisseni, Claudio; Grandi, Samuele; Kho, Kiang Wei; Clark, Alex S.; Hwang, J.; Hinds, E. A., E-mail: ed.hinds@imperial.ac.uk [Centre for Cold Matter, Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom)

    2015-08-15

    Dibenzoterrylene (DBT) molecules within a crystalline anthracene matrix show promise as quantum emitters for controlled, single photon production. We present the design and construction of a chamber in which we reproducibly grow doped anthracene crystals of optical quality that are several mm across and a few μm thick. We demonstrate control of the DBT concentration over the range 6–300 parts per trillion and show that these DBT molecules are stable single-photon emitters. We interpret our data with a simple model that provides some information on the vapour pressure of DBT.

  11. Research Progress and Development of Sapphire Fiber Sensor

    Directory of Open Access Journals (Sweden)

    Guochang ZHAO

    2014-07-01

    Full Text Available Sapphire fiber thermometers have become a new potential option in the field of high-temperature measurements. Recent research progress of sapphire fiber sensors is summarized; operational principles, advantages, disadvantages, and applications of sapphire fiber sensors are introduced. Research has shown that sapphire fiber sensors can be used to accurately measure very high temperatures in harsh environments and has been widely applied in fields such as aviation, metallurgy, the chemical industry, energy, and other high temperature measurement areas. Sapphire optical fiber temperature measurement technology will move toward miniaturization, intelligence following the advances in materials, micro-fabrication and communication technologies.

  12. Optical absorption in gel grown cadmium tartrate single crystals

    International Nuclear Information System (INIS)

    Arora, S K; Kothari, A J; Patel, R G; Chauha, K M; Chudasama, B N

    2006-01-01

    Single crystals of cadmium tartrate pentahydrate (CTP) have been grown by the famous gel technique. The slow and controlled reaction between Cd 2+ and (C 4 H 4 O 6 ) 2- ions in silica hydrogel results in formation of the insoluble product, CdC 4 H 4 O 6 .5H 2 O. Optical absorption spectra have been recorded in the range 200 to 2500 nm. Fundamental absorption edge for electronic transition has been analyzed. The direct allowed transition is found to be present in the region of relatively higher photon energy. Analysis of the segments of α 1/2 versus hν graph has been made to separate individual contribution of phonons. The phonons involved in the indirect transition are found to correspond to 335 and 420 cm -1 . Scattering of charge carriers in the lattice is found due to acoustic phonons

  13. Optical energy gaps and photoluminescence peaks of BaGa2S4:Er3+ and BaGa2Se4:Er3+ single crystals

    International Nuclear Information System (INIS)

    Choe, Sung-Hyu; Jin, Moon-Seog; Kim, Wha-Tek

    2005-01-01

    BaGa 2 S 4 :Er 3+ and BaGa 2 Se 4 :Er 3+ single crystals were grown by using the chemical transport reaction method. The optical energy gaps of the BaGa 2 S 4 :Er 3+ and the BaGa 2 Se 4 :Er 3+ single crystals were found to be 4.045 eV and 3.073 eV, respectively, at 11 K. The temperature dependence of the optical energy gap was well fitted by the Varshni equation. Sharp emission peaks were observed in the photoluminescence spectra of the single crystals and assigned to radiation recombination between split Stark levels of the Er 3+ ion.

  14. Nonlinearity Mechanism and Correction of Sapphire Fiber Temperature Sensor on Blackbody Cavity

    Directory of Open Access Journals (Sweden)

    Tiejun Cao

    2014-06-01

    Full Text Available Based on the principle of blackbody radiation, sapphire optic fiber temperature sensor has been more widely used in recent years, and its temperature range is between 800 ~ 2000 oC, and the response time is in 10-2 magnitude, and transient temperature measurement can be high precision in harsh environments. Nonlinear constraints on sapphire fiber temperature sensor affect the accuracy and stability of the sensor. In order to solve the nonlinear problems which exist in the measurement, at first, the sapphire fiber optic temperature sensor temperature measurement principle and nonlinear generation mechanism are studied; secondly piecewise linear interpolation and spline interpolation linearization algorithm is designed with combining the nonlinear characteristics of sapphire optical fiber temperature sensor, and the program is designed on its linear and associated signal processing. Experimental results show that a good linearization of sapphire fiber optic temperature sensor can been achieved in this method.

  15. Anisotropy of the optical absorption in layered single crystals of MoRe0.001Se1.999

    International Nuclear Information System (INIS)

    Vora, Mihir M.; Vora, Aditya M.

    2007-01-01

    Energy gap of MoRe 0.001 Se 1.999 single crystal has been determined by fundamental absorption methods. The incident light was polarized along c-axis of the crystals. The interpretion of the data is given within frameworks of two and three dimensional models. Both direct and indirect transitions are involved in the absorption process. The indirect transition was found to be allowed with two phonons participating in the process. The three dimensional model could be used to describe the optical properties of the single crystal. The energy gaps depend upon the amount of the intercalating Re material, which show the anisotropy of the chemical bonds. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. EPR and optical absorption studies of paramagnetic molecular ion (VO2+) in Lithium Sodium Acid Phthalate single crystal

    Science.gov (United States)

    Subbulakshmi, N.; Kumar, M. Saravana; Sheela, K. Juliet; Krishnan, S. Radha; Shanmugam, V. M.; Subramanian, P.

    2017-12-01

    Electron Paramagnetic Resonance (EPR) spectroscopic studies of VO2+ ions as paramagnetic impurity in Lithium Sodium Acid Phthalate (LiNaP) single crystal have been done at room temperature on X-Band microwave frequency. The lattice parameter values are obtained for the chosen system from Single crystal X-ray diffraction study. Among the number of hyperfine lines in the EPR spectra only two sets are reported from EPR data. The principal values of g and A tensors are evaluated for the two different VO2+ sites I and II. They possess the crystalline field around the VO2+ as orthorhombic. Site II VO2+ ion is identified as substitutional in place of Na1 location and the other site I is identified as interstitial location. For both sites in LiNaP, VO2+ are identified in octahedral coordination with tetragonal distortion as seen from the spin Hamiltonian parameter values. The ground state of vanadyl ion in the LiNaP single crystal is dxy. Using optical absorption data the octahedral and tetragonal parameters are calculated. By correlating EPR and optical data, the molecular orbital bonding parameters have been discussed for both sites.

  17. Synthesis of single-crystalline Al layers in sapphire

    International Nuclear Information System (INIS)

    Schlosser, W.; Lindner, J.K.N.; Zeitler, M.; Stritzker, B.

    1999-01-01

    Single-crystalline, buried aluminium layers were synthesized by 180 keV high-dose Al + ion implantation into sapphire at 500 deg. C. The approximately 70 nm thick Al layers exhibit in XTEM investigations locally abrupt interfaces to the single-crystalline Al 2 O 3 top layer and bulk, while thickness and depth position are subjected to variations. The layers grow by a ripening process of oriented Al precipitates, which at low doses exist at two different orientations. With increasing dose, precipitates with one out of the two orientations are observed to exist preferentially, finally leading to the formation of a single-crystalline layer. Al outdiffusion to the surface and the formation of spherical Al clusters at the surface are found to be competing processes to buried layer formation. The formation of Al layers is described by Rutherford Backscattering Spectroscopy (RBS), Cross-section transmission electron microscopy (XTEM) and Scanning electron microscopy (SEM) studies as a function of dose, temperature and substrate orientation

  18. Optical and dielectric studies of KH2PO4 crystal influenced by organic ligand of citric acid and l-valine: A single crystal growth and comparative study

    Directory of Open Access Journals (Sweden)

    Mohd Anis

    Full Text Available In the present study pure, citric acid (CA and l-valine (LV doped potassium dihydrogen phosphate (KDP crystals have been grown with the aim to investigate the nonlinear optical applications facilitated by UV–visible, third order nonlinear optical (TONLO and dielectric properties. The structural parameters of grown crystals have been confirmed by single crystal X-ray diffraction analysis. The enhancement in optical transparency of KDP crystal due to addition of CA and LV has been examined within 200–900 nm by means of UV–visible spectral analysis. In addition, the transmittance data have been used to evaluate the effect of dopants on reflectance, refractive index and extinction coefficient of grown crystals in the visible region. The Z-scan analysis has been performed at 632.8 nm to identify the nature of photoinduced nonlinear refraction and nonlinear absorption in doped KDP crystals. The influence of π-bonded ligand of dopant CA and LV on TONLO susceptibility (χ3, refractive index (n2 and absorption coefficient (β of KDP crystals has been evaluated to discuss laser assisted device applications. The decrease in dielectric constant and dielectric loss of KDP crystal due to addition of CA and LV has been explored using the temperature dependent dielectric studies. Keywords: Crystal growth, Nonlinear optical materials, UV–visible studies, Z-scan analysis, Dielectric studies

  19. Reversible air-induced optical and electrical modulation of methylammonium lead bromide (MAPbBr3) single crystals

    Science.gov (United States)

    Zhang, Huotian; Liu, Yiting; Lu, Haizhou; Deng, Wan; Yang, Kang; Deng, Zunyi; Zhang, Xingmin; Yuan, Sijian; Wang, Jiao; Niu, Jiaxin; Zhang, Xiaolei; Jin, Qingyuan; Feng, Hongjian; Zhan, Yiqiang; Zheng, Lirong

    2017-09-01

    The photoluminescence (PL) variations of organic-inorganic hybrid lead halide perovskites in different atmospheres are well documented, while the fundamental mechanism still lacks comprehensive understandings. This study reports the reversible optical and electrical properties of methylammonium lead bromide (MAPbBr3 or CH3NH3PbBr3) single crystals caused by air infiltration. With the change in the surrounding atmosphere from air to vacuum, the PL intensity of perovskite single crystals decreases, while the conductivity increases. By means of first-principles computational studies, the shallow trap states are considered as key elements in PL and conductivity changes. These results have important implications for the characterization and application of organic-inorganic hybrid lead halide perovskites in vacuum.

  20. Studies on growth, crystal structure and characterization of novel organic nicotinium trifluoroacetate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Dhanaraj, P.V. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Rajesh, N.P., E-mail: rajeshnp@hotmail.com [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Sundar, J. Kalyana; Natarajan, S. [Department of Physics, Madurai Kamaraj University, Madurai 625 021 (India); Vinitha, G. [Department of Physics, Crescent Engineering College, Chennai 600 048 (India)

    2011-09-15

    Highlights: {yields} Good quality crystals of nicotinium trifluoroacetate in monoclinic system were grown for first time. {yields} Nicotinium trifluoroacetate crystal exhibits third order nonlinear optical properties. {yields} The optical spectrum of nicotinium trifluoroacetate crystal reveals the wide transmission in the entire range with cutoff wavelength at 286 nm. {yields} Nicotinium trifluoroacetate is a low dielectric constant material. - Abstract: An organic material, nicotinium trifluoroacetate (NTF) was synthesized and single crystals in monoclinic system were grown from aqueous solution for the first time. Its solubility and metastable zone width were estimated. The crystal structure of NTF was analyzed to reveal the molecular arrangements and the formation of hydrogen bonds in the crystal. High-resolution X-ray diffraction rocking curve measurements were performed to analyze the structural perfection of the grown crystals. Functional groups in NTF were identified by Fourier transform infrared spectral analysis. Thermal behaviour and stability of NTF were studied by thermogravimetric and differential thermal analysis and differential scanning calorimetry. Mechanical and dielectric properties of NTF crystals were analyzed. Optical studies reveal that NTF crystals are transparent in the wavelength range 286-1100 nm. The third order nonlinear optical parameters of NTF were derived by the Z-scan technique.

  1. Coupling of single nitrogen-vacancy defect centers in diamond nanocrystals to optical antennas and photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wolters, Janik; Kewes, Guenter; Schell, Andreas W.; Aichele, Thomas; Benson, Oliver [Humboldt-Universitaet zu Berlin, Institut fuer Physik, Berlin (Germany); Nuesse, Nils; Schoengen, Max; Loechel, Bernd [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Hanke, Tobias; Leitenstorfer, Alfred [Department of Physics and Center for Applied Photonics, Universitaet Konstanz, Konstanz (Germany); Bratschitsch, Rudolf [Department of Physics and Center for Applied Photonics, Universitaet Konstanz, Konstanz (Germany); Technische Universitaet Chemnitz, Institut fuer Physik, Chemnitz (Germany)

    2012-05-15

    We demonstrate the ability to modify the emission properties and enhance the interaction strength of single-photon emitters coupled to nanophotonic structures based on metals and dielectrics. Assembly of individual diamond nanocrystals, metal nanoparticles, and photonic crystal cavities to meta-structures is introduced. Experiments concerning controlled coupling of single defect centers in nanodiamonds to optical nanoantennas made of gold bowtie structures are reviewed. By placing one and the same emitter at various locations with high precision, a map of decay rate enhancements was obtained. Furthermore, we demonstrate the formation of a hybrid cavity quantum electrodynamics system in which a single defect center is coupled to a single mode of a gallium phosphite photonic crystal cavity. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Growth, optical and EPR studies of {sup 151}Eu{sup 2+}:YAG single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Petrosyan, A.G., E-mail: pet@ipr.sci.am [Institute for Physical Research, National Academy of Sciences, Ashtarak, 0203 (Armenia); Asatryan, H.R. [Ioffe Physical-Technical Institute, Politekhnicheskaya ul. 26, St. Petersburg, 194021 (Russian Federation); Hovhannesyan, K.L.; Derdzyan, M.V. [Institute for Physical Research, National Academy of Sciences, Ashtarak, 0203 (Armenia); Feofilov, S.P. [Ioffe Physical-Technical Institute, Politekhnicheskaya ul. 26, St. Petersburg, 194021 (Russian Federation); Eganyan, A.V.; Sargsyan, R.S. [Institute for Physical Research, National Academy of Sciences, Ashtarak, 0203 (Armenia)

    2017-01-01

    Single crystals of {sup 151}Eu:YAG were grown by the vertical Bridgman method using Eu{sub 2}O{sub 3} with isotopic enrichment of {sup 151}Eu of 97.5%. Additional Hf{sup 4+}or Si{sup 4+} ions were introduced to favor a high concentrations of Eu{sup 2+}. As compared to Eu:YAG with natural isotope composition, the EPR spectra of YAG doped with {sup 151}Eu isotope show a reduced number of hyperfine structure components and a well-resolved structure of a bigger number of electronic transitions. Optical properties of obtained crystals and the effects of heat treatments under oxidizing and reducing conditions are reported. Based on the analysis of Eu{sup 3+} distribution in oxidized Eu,Hf:YAG, in comparison to that in Eu:YAG, the concentration of Eu{sup 2+} in as-grown Eu,Hf:YAG is determined. - Highlights: • YAG:Eu,Hf single crystals containing only {sup 151}Eu isotopes were prepared. • isotopic enriched crystals gave a well-resolved EPR hyperfine structure of Eu{sup 2+} centers. • the redox ratio was followed through the Eu{sup 2+} associated absorption band at 250 nm. • the band intensities at 378 nm correlate with the Eu{sup 2+} concentration.

  3. Optical and structural characterization of GaSb and Te-doped GaSb single crystals

    International Nuclear Information System (INIS)

    Tirado-Mejia, L.; Villada, J.A.; Rios, M. de los; Penafiel, J.A.; Fonthal, G.; Espinosa-Arbelaez, D.G.; Ariza-Calderon, H.; Rodriguez-Garcia, M.E.

    2008-01-01

    Optical and structural properties of GaSb and Te-doped GaSb single crystals are reported herein. Utilizing the photoreflectance technique, the band gap energy for doped samples was obtained at 0.814 eV. Photoluminescence (PL) spectra showed a peak at 0.748 eV that according to this research, belongs to electronic states of pure GaSb and not to the longitudinal optical (LO) phonon replica as has been reported by other authors. Analysis of the full width at half maximum (FWHM) values of X-ray diffraction, as well as micro-Raman peaks showed that the inclusion of Te decreases the crystalline quality

  4. Linear, non-linear and thermal properties of single crystal of LHMHCl

    Science.gov (United States)

    Kulshrestha, Shobha; Shrivastava, A. K.

    2018-05-01

    The single crystal of amino acid of L-histidine monohydrochloride was grown by slow evaporation technique at room temperature. High optical quality and appropriate size of crystals were grown under optimized growth conditions. The grown crystals were transparent. Crystals are characterized with different characterizations such as Solubility test, UV-Visible, optical band gap (Eg). With the help of optical data to be calculate absorption coefficient (α), extinction coefficient (k), refractive index (n), dielectric constant (ɛ). These optical constants are shows favorable conditions for photonics devices. Second harmonic generation (NLO) test show the green light emission which is confirm that crystal have properties for laser application. Thermal stability of grown crystal is confirmed by TG/DTA.

  5. Synthesis of titanium sapphire by ion implantation

    International Nuclear Information System (INIS)

    Morpeth, L.D.; McCallum, J.C.; Nugent, K.W.

    1998-01-01

    Since laser action was first demonstrated in titanium sapphire (Ti:Al 2 O 3 ) in 1982, it has become the most widely used tunable solid state laser source. The development of a titanium sapphire laser in a waveguide geometry would yield an elegant, compact, versatile and highly tunable light source useful for applications in many areas including optical telecommunications. We are investigating whether ion implantation techniques can be utilised to produce suitable crystal quality and waveguide geometry for fabrication of a Ti:Al 2 O 3 waveguide laser. The implantation of Ti and O ions into c-axis oriented α-Al 2 O 3 followed by subsequent thermal annealing under various conditions has been investigated as a means of forming the waveguide and optimising the fraction of Ti ions that have the correct oxidation state required for laser operation. A Raman Microprobe is being used to investigate the photo-luminescence associated with Ti 3+ ion. Initial photoluminescence measurements of ion implanted samples are encouraging and reveal a broad luminescence profile over a range of ∼ .6 to .9 μm, similar to that expected from Ti 3+ . Rutherford Backscattering and Ion Channelling analysis have been used to study the crystal structure of the samples following implantation and annealing. This enables optimisation of the implantation parameters and annealing conditions to minimise defect levels which would otherwise limit the ability of light to propagate in the Ti:Al 2O 3 waveguide. (authors)

  6. Structural and optical properties of a NaCl single crystal doped with CuO nanocrystals

    International Nuclear Information System (INIS)

    Addala, S.; Bouhdjer, L.; Halimi, O.; Boudine, B.; Sebais, M.; Chala, A.; Bouhdjar, A.

    2013-01-01

    A cupric oxide (CuO) nanocrystal-doped NaCl single crystal and a pure NaCl single crystal are grown by using the Czochralski (Cz) method. A number of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, optical absorption in the UV—visible range, and photoluminescence (PL) spectroscopy are used to characterize the obtained NaCl and NaCl:CuO crystals. It is observed that the average radius of CuO crystallites in NaCl:CuO crystal is about 29.87 nm, as derived from the XRD data analysis. Moreover, FT-IR and Raman spectroscopy results confirm the existence of the monoclinic CuO phase in NaCl crystal. UV—visible absorption measurements indicate that the band gap of the NaCl:CuO crystal is 434 nm (2.85 eV), and it shows a significant amount of blue-shift (ΔE g = 1 eV) in the band gap energy of CuO, which is due to the quantum confinement effect exerted by the CuO nanocrystals. The PL spectrum of the NaCl:CuO shows a broad emission band centred at around 438 nm, which is consistent with the absorption measurement. (interdisciplinary physics and related areas of science and technology)

  7. Prospects for the synthesis of large single-crystal diamonds

    International Nuclear Information System (INIS)

    Khmelnitskiy, R A

    2015-01-01

    The unique properties of diamond have stimulated the study of and search for its applications in many fields, including optics, optoelectronics, electronics, biology, and electrochemistry. Whereas chemical vapor deposition allows the growth of polycrystalline diamond plates more than 200 mm in diameter, most current diamond application technologies require large-size (25 mm and more) single-crystal diamond substrates or films suitable for the photolithography process. This is quite a challenge, because the largest diamond crystals currently available are 10 mm or less in size. This review examines three promising approaches to fabricating large-size diamond single crystals: growing large-size single crystals, the deposition of heteroepitaxial diamond films on single-crystal substrates, and the preparation of composite diamond substrates. (reviews of topical problems)

  8. Temperature dependence of InN growth on (0001) sapphire substrates by atmospheric pressure hydride vapor phase epitaxy

    International Nuclear Information System (INIS)

    Kumagai, Yoshinao; Adachi, Hirokazu; Otake, Aya; Higashikawa, Yoshihiro; Togashi, Rie; Murakami, Hisashi; Koukitu, Akinori

    2010-01-01

    The temperature dependence of InN growth on (0001) sapphire substrates by atmospheric pressure hydride vapor phase epitaxy (HVPE) was investigated. N-polarity single-crystal InN layers were successfully grown at temperatures ranging from 400 to 500 C. The a and c lattice constants of InN layers grown at 450 C or below were slightly larger than those of InN layers grown above 450 C due to oxygen incorporation that also increased the carrier concentration. The optical absorption edge of the InN layer decreased from above 2.0 to 0.76 eV when the growth temperature was increased from 450 to 500 C. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Contribution to the microwave characterisation of superconductive materials by means of sapphire resonators

    International Nuclear Information System (INIS)

    Hanus, Xavier

    1993-01-01

    The objective of this research thesis is to find a compact resonant structure which would allow the residual surface impedance of superconductive samples to be simply, quickly and economically characterised. The author first explains why he decided to use a sapphire single-crystal as inner dielectric, given some performance reached by resonant structures equipped with such inner dielectrics, and given constraints adopted from the start. He explains the origin of microwave losses which appear in this type of resonant structure, i.e. respectively the surface impedance as far as metallic losses are concerned, and the sapphire dielectric loss angle for as far as dielectric losses are concerned. The experimental installation and the principle of microwave measurements are described. The performance of different possible solutions of resonant structures from starting criteria is presented. The solution of the cavity-sapphire with a TE 011 resonant mode is derived [fr

  10. Optically Anomalous Crystals

    CERN Document Server

    Shtukenberg, Alexander; Kahr, Bart

    2007-01-01

    Optical anomalies in crystals are puzzles that collectively constituted the greatest unsolved problems in crystallography in the 19th Century. The most common anomaly is a discrepancy between a crystal’s symmetry as determined by its shape or by X-ray analysis, and that determined by monitoring the polarization state of traversing light. These discrepancies were perceived as a great impediment to the development of the sciences of crystals on the basis of Curie’s Symmetry Principle, the grand organizing idea in the physical sciences to emerge in the latter half of the 19th Century. Optically Anomalous Crystals begins with an historical introduction covering the contributions of Brewster, Biot, Mallard, Brauns, Tamman, and many other distinguished crystallographers. From this follows a tutorial in crystal optics. Further chapters discuss the two main mechanisms of optical dissymmetry: 1. the piezo-optic effect, and 2. the kinetic ordering of atoms. The text then tackles complex, inhomogeneous crystals, and...

  11. Free-standing nanomechanical and nanophotonic structures in single-crystal diamond

    Science.gov (United States)

    Burek, Michael John

    Realizing complex three-dimensional structures in a range of material systems is critical to a variety of emerging nanotechnologies. This is particularly true of nanomechanical and nanophotonic systems, both relying on free-standing small-scale components. In the case of nanomechanics, necessary mechanical degrees of freedom require physically isolated structures, such as suspended beams, cantilevers, and membranes. For nanophotonics, elements like waveguides and photonic crystal cavities rely on light confinement provided by total internal reflection or distributed Bragg reflection, both of which require refractive index contrast between the device and surrounding medium (often air). Such suspended nanostructures are typically fabricated in a heterolayer structure, comprising of device (top) and sacrificial (middle) layers supported by a substrate (bottom), using standard surface nanomachining techniques. A selective, isotropic etch is then used to remove the sacrificial layer, resulting in free-standing devices. While high-quality, crystalline, thin film heterolayer structures are readily available for silicon (as silicon-on-insulator (SOI)) or III-V semiconductors (i.e. GaAs/AlGaAs), there remains an extensive list of materials with attractive electro-optic, piezoelectric, quantum optical, and other properties for which high quality single-crystal thin film heterolayer structures are not available. These include complex metal oxides like lithium niobate (LiNbO3), silicon-based compounds such as silicon carbide (SiC), III-V nitrides including gallium nitride (GaN), and inert single-crystals such as diamond. Diamond is especially attractive for a variety of nanoscale technologies due to its exceptional physical and chemical properties, including high mechanical hardness, stiffness, and thermal conductivity. Optically, it is transparent over a wide wavelength range (from 220 nm to the far infrared), has a high refractive index (n ~ 2.4), and is host to a vast

  12. Single-pulse CARS based multimodal nonlinear optical microscope for bioimaging.

    Science.gov (United States)

    Kumar, Sunil; Kamali, Tschackad; Levitte, Jonathan M; Katz, Ori; Hermann, Boris; Werkmeister, Rene; Považay, Boris; Drexler, Wolfgang; Unterhuber, Angelika; Silberberg, Yaron

    2015-05-18

    Noninvasive label-free imaging of biological systems raises demand not only for high-speed three-dimensional prescreening of morphology over a wide-field of view but also it seeks to extract the microscopic functional and molecular details within. Capitalizing on the unique advantages brought out by different nonlinear optical effects, a multimodal nonlinear optical microscope can be a powerful tool for bioimaging. Bringing together the intensity-dependent contrast mechanisms via second harmonic generation, third harmonic generation and four-wave mixing for structural-sensitive imaging, and single-beam/single-pulse coherent anti-Stokes Raman scattering technique for chemical sensitive imaging in the finger-print region, we have developed a simple and nearly alignment-free multimodal nonlinear optical microscope that is based on a single wide-band Ti:Sapphire femtosecond pulse laser source. Successful imaging tests have been realized on two exemplary biological samples, a canine femur bone and collagen fibrils harvested from a rat tail. Since the ultra-broad band-width femtosecond laser is a suitable source for performing high-resolution optical coherence tomography, a wide-field optical coherence tomography arm can be easily incorporated into the presented multimodal microscope making it a versatile optical imaging tool for noninvasive label-free bioimaging.

  13. Development of Auto-Seeding System Using Image Processing Technology in the Sapphire Crystal Growth Process via the Kyropoulos Method

    Directory of Open Access Journals (Sweden)

    Churl Min Kim

    2017-04-01

    Full Text Available The Kyropoulos (Ky and Czochralski (Cz methods of crystal growth are used for large-diameter single crystals. The seeding process in these methods must induce initial crystallization by initiating contact between the seed crystals and the surface of the melted material. In the Ky and Cz methods, the seeding process lays the foundation for ingot growth during the entire growth process. When any defect occurs in this process, it is likely to spread to the entire ingot. In this paper, a vision system was constructed for auto seeding and for observing the surface of the melt in the Ky method. An algorithm was developed to detect the time when the internal convection of the melt is stabilized by observing the shape of the spoke pattern on the melt material surface. Then, the vision system and algorithm were applied to the growth furnace, and the possibility of process automation was examined for sapphire growth. To confirm that the convection of the melt was stabilized, the position of the island (i.e., the center of a spoke pattern was detected using the vision system and image processing. When the observed coordinates for the center of the island were compared with the coordinates detected from the image processing algorithm, there was an average error of 1.87 mm (based on an image with 1024 × 768 pixels.

  14. Effect of SHI irradiation on structural, surface morphological and optical studies of CVT grown ZnSSe single crystals

    International Nuclear Information System (INIS)

    Kannappan, P.; Asokan, K.; Krishna, J.B.M.; Dhanasekaran, R.

    2013-01-01

    Highlights: •CVT grown ZnSSe single crystals were irradiated with 120 MeV Au ion. •The GIXRD results show the FWHM increases with increasing ion fluency. •The AFM study show the surface roughness increases with ion fluency. •The optical band gap energy vary with increasing ion fluency. •The PL emission decreases with increasing ion fluency. -- Abstract: The ZnSSe single crystals grown by chemical vapour transport (CVT) method have been irradiated by 120 MeV Au 9+ ions at room temperature with fluences of 1 × 10 12 and 5 × 10 12 ions/cm 2 . The grazing incidence X-ray diffraction (GIXRD) results show that the full width at half maximum (FWHM) value for the as grown ZnSSe crystal is 0.215°; and for the irradiated samples, the FWHM values are 0.413° and 0.625°, with the increase of ion fluences. The atomic force microscopy (AFM) studies reveal the formation of the pits and islands due to irradiation. The optical absorption cut off wavelength is found to be 441 nm for as grown ZnSSe crystal. The cut off values are increased to 447 nm and 457 nm for the irradiated samples with increasing ion fluency. The photoluminescence studies show the emission for the as grown ZnSSe is 590 nm whereas for the irradiated samples in the emission range it is 580–590 nm and 575–595 nm due to SHI irradiation. FT-Raman spectra analysis has been made for the ZnSSe single crystals and irradiated samples. The results are discussed in detail

  15. Effect of SHI irradiation on structural, surface morphological and optical studies of CVT grown ZnSSe single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kannappan, P. [Crystal Growth Centre, Anna University, Chennai 600 025 (India); Asokan, K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Krishna, J.B.M. [UGC-DAE Consortium for Scientific Research, III-/LB-8, Bidhan nagar, Kolkata 700 098 (India); Dhanasekaran, R., E-mail: rdcgc@yahoo.com [Crystal Growth Centre, Anna University, Chennai 600 025 (India)

    2013-12-15

    Highlights: •CVT grown ZnSSe single crystals were irradiated with 120 MeV Au ion. •The GIXRD results show the FWHM increases with increasing ion fluency. •The AFM study show the surface roughness increases with ion fluency. •The optical band gap energy vary with increasing ion fluency. •The PL emission decreases with increasing ion fluency. -- Abstract: The ZnSSe single crystals grown by chemical vapour transport (CVT) method have been irradiated by 120 MeV Au{sup 9+} ions at room temperature with fluences of 1 × 10{sup 12} and 5 × 10{sup 12} ions/cm{sup 2}. The grazing incidence X-ray diffraction (GIXRD) results show that the full width at half maximum (FWHM) value for the as grown ZnSSe crystal is 0.215°; and for the irradiated samples, the FWHM values are 0.413° and 0.625°, with the increase of ion fluences. The atomic force microscopy (AFM) studies reveal the formation of the pits and islands due to irradiation. The optical absorption cut off wavelength is found to be 441 nm for as grown ZnSSe crystal. The cut off values are increased to 447 nm and 457 nm for the irradiated samples with increasing ion fluency. The photoluminescence studies show the emission for the as grown ZnSSe is 590 nm whereas for the irradiated samples in the emission range it is 580–590 nm and 575–595 nm due to SHI irradiation. FT-Raman spectra analysis has been made for the ZnSSe single crystals and irradiated samples. The results are discussed in detail.

  16. Nucleation kinetics and growth aspects of semi organic non-linear optical bis thiourea cadmium acetate single crystals

    International Nuclear Information System (INIS)

    Sankar, R.; Raghavan, C.M.; Jayavel, R.

    2006-01-01

    Nucleation parameters such as metastable zone width, induction period and interfacial energy have been determined for the aqueous solution growth of bis thiourea cadmium acetate (BTCA) single crystals. Solubility of BTCA has been determined for various temperatures. Metastable zone width and induction period values have been estimated in order to optimize the growth parameters. The interfacial tension values derived from experimentally determined induction period are found to be comparable with theoretical values. Bulk crystals of BTCA have been grown using the optimized growth parameters. The grown crystals have been subjected to structural, optical and mechanical property studies. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Order in nanometer thick intergranular films at Au-sapphire interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Baram, Mor [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Garofalini, Stephen H. [Department of Materials Science and Engineering, Rutgers University, Piscataway, NJ 08854-8065 (United States); Kaplan, Wayne D., E-mail: kaplan@tx.technion.ac.il [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel)

    2011-08-15

    Highlights: {yields} Au particles were equilibrated on (0 0 0 1) sapphire in the presence of anorthite. {yields} 1.2 nm thick equilibrium films (complexions) were formed at the Au-sapphire interfaces. {yields} Quantitative HRTEM was used to study the atomistic structure of the films. {yields} Structural order was observed in the 1.2 nm thick films adjacent to the sapphire crystal. {yields} This demonstrates that ordering is an intrinsic part of equilibrium intergranular films. - Abstract: In recent years extensive studies on interfaces have shown that {approx}1 nm thick intergranular films (IGF) exist at interfaces in different material systems, and that IGF can significantly affect the materials' properties. However, there is great deal of uncertainty whether such films are amorphous or partially ordered. In this study specimens were prepared from Au particles that were equilibrated on sapphire substrates in the presence of anorthite glass, leading to the formation of 1.2 nm thick IGF at the Au-sapphire interfaces. Site-specific cross-section samples were characterized using quantitative high resolution transmission electron microscopy to study the atomistic structure of the films. Order was observed in the 1.2 nm thick films adjacent to the sapphire crystal in the form of 'Ca cages', experimentally demonstrating that ordering is an intrinsic part of IGF, as predicted from molecular dynamics and diffuse interface theory.

  18. Magnetic, transport, and optical properties of Ca{sub 0.85}Eu{sub 0.15}MnO{sub 3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Naumov, S.V., E-mail: naumov@imp.uran.ru [Institute of Metal Physics, Ural Branch of RAS, Kovalevskaya Street 18, Ekaterinburg 620990 (Russian Federation); Loshkareva, N.N.; Mostovshchikova, E.V.; Solin, N.I.; Korolev, A.V.; Arbuzova, T.I.; Telegin, S.V.; Patrakov, E.I. [Institute of Metal Physics, Ural Branch of RAS, Kovalevskaya Street 18, Ekaterinburg 620990 (Russian Federation)

    2013-01-01

    Magnetic, transport and optical properties of the Ca{sub 0.85}Eu{sub 0.15}MnO{sub 3} single crystal are studied and discussed in comparison with the properties of polycrystalline sample. The magnetic data show existence the two magnetic phase transitions under cooling: the transition near 150 K occurs from the paramagnetic orthorhombic to C-type antiferromagnetic monoclinic phase with the charge/orbital ordering in some part of the crystal; and at 90 K the transition from the paramagnetic to G-type antiferromagnetic phase takes place in another part of the crystal with the orthorhombic structure. The magnetoresistance of the Ca{sub 0.85}Eu{sub 0.15}MnO{sub 3} single crystal has features at temperatures of these phase transitions. Differences in the properties of single crystal and polycrystalline sample with the same content of Eu are associated with the ordering of oxygen vacancies that appear under the crystal growth. The reflection spectra in infrared range confirm the existence of the electron conductivity in a narrow band at room temperature.

  19. Microscopic single-crystal refractometry as a function of wavelength

    International Nuclear Information System (INIS)

    DeLoach, L.D.

    1994-01-01

    The refractive indices of crystal fragments 50--200 μm in size can be measured for light wavelengths between 365 and 1100 nm with a spindle-stage refractometer. Established methods from optical crystallograpy are used to orient a crystal on the microscope spindle stage and then to match its refractive index to an immersion fluid. The refractive index of the fluid for the wavelength of light and matching temperature is determined by comparison of a reference crystal on a second spindle axis with the fluid under the match conditions. Investigations of new nonlinear-optical crystals admirably demonstrate the advantages of measuring the refractive index to ± 0.0004 in small single crystals

  20. Optically pumped lasing in single crystals of organometal halide perovskites prepared by cast-capping method

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Van-Cao; Katsuki, Hiroyuki; Yanagi, Hisao, E-mail: yanagi@ms.naist.jp [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Sasaki, Fumio [Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2016-06-27

    A simple “cast-capping” method is adopted to prepare single-crystal perovskites of methyl ammonium lead bromide (CH{sub 3}NH{sub 3}PbBr{sub 3}). By capping a CH{sub 3}NH{sub 3}PbBr{sub 3} solution casted on one substrate with another substrate such as glass, mica, and distributed Bragg reflector (DBR), the slow evaporation of solvent enables large-size cubic crystals to grow between the two substrates. Under optical pumping, edge-emitting lasing is observed based on Fabry–Pérot resonation between parallel side facets of a strip-shaped crystal typically with a lateral cavity length of a few tens of μm. On the other hand, vertical-cavity surface-emitting lasing (VCSEL) is obtained from a planar crystal grown between two DBRs with a cavity thickness of a few μm. Simultaneous detection of those edge- and surface-emissions reveals that the threshold excitation fluence of VCSEL is higher than that of the edge-emitting lasing due to thickness gradient in the planar crystal.

  1. Air-void embedded GaN-based light-emitting diodes grown on laser drilling patterned sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hao; Li, Yufeng; Wang, Shuai; Feng, Lungang; Xiong, Han; Yun, Feng, E-mail: fyun2010@mail.xjtu.edu.cn [Key Laboratory of Physical Electronics and Devices of Ministry of Education and Shaanxi Provincial Key Laboratory of Photonics and Information Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Solid-State Lighting Engineering Research Center, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Su, Xilin [Shaanxi Supernova Lighting Technology Co., Ltd., Xi’an, Shaanxi 710075 (China)

    2016-07-15

    Air-void structure was introduced in GaN-based blue light-emitting diodes (LED) with one-step growth on periodic laser drilling patterned sapphire substrate, which free of any photolithography or wet/dry etching process. The influence of filling factors (FF) of air-void on crystal quality and optical performance were investigate. Transmission electron microscopy images and micro-Raman spectroscopy indicated that the dislocation was bended and the partially compressed strain was released. When FF was 55.43%, compared with the LED structure grown on flat sapphire substrate, the incorporation of air-void was observed to reduce the compressed stress of ∼20% and the luminance intensity has improved by 128%. Together with the simulated reflection intensity enhancement by finite difference time-domain (FDTD) method, we attribute the enhanced optical performance to the combined contribution of strong back-side light reflection of air-void and better GaN epitaxial quality. This approach provides a simple replacement to the conventional air-void embedded LED process.

  2. Growth and characterization of β-Ga2O3 crystals

    Science.gov (United States)

    Nikolaev, V. I.; Maslov, V.; Stepanov, S. I.; Pechnikov, A. I.; Krymov, V.; Nikitina, I. P.; Guzilova, L. I.; Bougrov, V. E.; Romanov, A. E.

    2017-01-01

    Here we report on the growth and characterization of β-Ga2O3 bulk crystals and polycrystalline layer on different substrates. Bulk β-Ga2O3 crystals were produced by free crystallisation of gallium oxide melt in sapphire crucible. Transparent single crystals measuring up to 8 mm across were obtained. Good structural quality was confirmed by x-ray diffraction rocking curve FWHM values of 46″. Young's modulus, shear modulus and hardness of the β-Ga2O3 crystals were measured by nanoindentation and Vickers microindentation techniques. Polycrystalline β-Ga2O3 films were deposited on silicon and sapphire substrates by sublimation method. It was found that structure and morphology of the films were greatly influenced by the material and orientation of the substrates. The best results were achieved on a-plane sapphire substrates where predominantly (111) oriented films were obtained.

  3. Optical characteristics of BaGa{sub 2}S{sub 4}:Ho{sup 3+} and BaGa{sub 2}Se{sub 4}:Ho{sup 3+} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Sung-Hyu [Chosun University, Kwangju (Korea, Republic of); Jin, Moon-Seog [Dongshin University, Naju (Korea, Republic of); Kim, Wha-Tek [Chonnam National University, Kwangju (Korea, Republic of)

    2005-11-15

    BaGa{sub 2}S{sub 4}, BaGa{sub 2}S{sub 4}:Ho{sup 3+}, BaGa{sub 2}Se{sub 4}, and BaGa{sub 2}Se{sub 4}:Ho{sup 3+} single crystals were grown by using the chemical transport reaction method. The optical energy gaps of the single crystals were investigated in the temperature region from 11 K to 300 K. The temperature dependence of the optical energy gap was well fitted by the Varshni equation. Two broad emission bands were observed in the photoluminescence spectra of the single crystals. These bands were attributed to donor-acceptor pair recombinations. Sharp emission peaks were observed in the BaGa{sub 2}S{sub 4}:Ho{sup 3+} and the BaGa{sub 2}Se{sub 4}:Ho{sup 3+} single crystals and were assigned to radiation recombination between split Stark levels of Ho{sup 3+}.

  4. Effect of indium and antimony doping in SnS single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chaki, Sunil H., E-mail: sunilchaki@yahoo.co.in; Chaudhary, Mahesh D.; Deshpande, M.P.

    2015-03-15

    Highlights: • Single crystals growth of pure SnS, indium doped SnS and antimony doped SnS by direct vapour transport (DVT) technique. • Doping of In and Sb occurred in SnS single crystals by cation replacement. • The replacement mechanism ascertained by EDAX, XRD and substantiated by Raman spectra analysis. • Dopants concentration affects the optical energy bandgap. • Doping influences electrical transport properties. - Abstract: Single crystals of pure SnS, indium (In) doped SnS and antimony (Sb) doped SnS were grown by direct vapour transport (DVT) technique. Two doping concentrations of 5% and 15% each were employed for both In and Sb dopants. Thus in total five samples were studied viz., pure SnS (S1), 5% In doped SnS (S2), 15% In doped SnS (S3), 5% Sb doped SnS (S4) and 15% Sb doped SnS (S5). The grown single crystal samples were characterized by evaluating their surface microstructure, stoichiometric composition, crystal structure, Raman spectroscopy, optical and electrical transport properties using appropriate techniques. The d.c. electrical resistivity and thermoelectric power variations with temperature showed semiconducting and p-type nature of the as-grown single crystal samples. The room temperature Hall Effect measurements further substantiated the semiconducting and p-type nature of the as-grown single crystal samples. The obtained results are deliberated in detail.

  5. Mechanical and optical nanodevices in single-crystal quartz

    Science.gov (United States)

    Sohn, Young-Ik; Miller, Rachel; Venkataraman, Vivek; Lončar, Marko

    2017-12-01

    Single-crystal α-quartz, one of the most widely used piezoelectric materials, has enabled a wide range of timing applications. Owing to the fact that an integrated thin-film based quartz platform is not available, most of these applications rely on macroscopic, bulk crystal-based devices. Here, we show that the Faraday cage angled-etching technique can be used to realize nanoscale electromechanical and photonic devices in quartz. Using this approach, we demonstrate quartz nanomechanical cantilevers and ring resonators featuring Qs of 4900 and 8900, respectively.

  6. CO2 laser-induced directional recrystallization to produce single crystal silicon-core optical fibers with low loss

    OpenAIRE

    Healy, Noel; Fokine, Michael; Franz, Yohann; Hawkins, Thomas; Jones, Maxwell; Ballato, John; Peacock, Anna C.; Gibson, Ursula J.

    2016-01-01

    Reduced losses in silicon-core fibers are obtained using CO2 laser directional recrystallization of the core. Single crystals with aspect ratios up to 1500:1 are reported, limited by the scan range of the equipment. This processing technique holds promise for bringing crystalline silicon-core fibers to a central role in nonlinear optics and signal processing applications.

  7. Single-crystalline AlN growth on sapphire using physical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas-Valencia, Andres M., E-mail: andres.cardenas@sri.co [SRI International (United States); Onishi, Shinzo; Rossie, Benjamin [SRI International (United States)

    2011-02-07

    A novel technique for growing single crystalline aluminum nitride (AlN) films is presented. The novelty of the technique, specifically, comes from the use of an innovative physical vapor deposition magnetron sputtering tool, which embeds magnets into the target material. A relatively high deposition rates is achieved ({approx}0.2 {mu}m/min), at temperatures between 860 and 940 {sup o}C. The AlN, grown onto sapphire, is single-crystalline as evidenced by observation using transmission electron microscopy. Tool configuration and growth conditions are discussed, as well as a first set of other analytical results, namely, x-ray diffraction and ultraviolet-visible transmission spectrophotometry.

  8. Optically stimulated luminescence of Tb{sup 3+}/Sm{sup 3+} doubly doped K{sub 2}YF{sub 5} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, L.; Marcazzo, J.; Santiago, M.; Caselli, E. [Universidad Nacional del Centro de la Provincia de Buenos Aires, Instituto de Fisica Arroyo Seco, Gral. Pinto 399, B7000GHG, Tandil (Argentina); Khaidukov, N. M., E-mail: jmarcass@exa.unicen.edu.ar [Kurnakov Institute of General and Inorganic Chemistry, RAS, Leninskii Prospekt 31, 119991 Moscow (Russian Federation)

    2014-08-15

    In this work optically stimulated luminescence (OSL) properties of K{sub 2}YF{sub 5} crystals doubly doped with Tb{sup 3+} and Sm{sup 3+} ions have been investigated for the first time. OSL responses for different dopant concentration and for optical stimulation with different wavelengths have been analyzed for each compound. Dosimetric properties of the most efficient composition, namely, K{sub 2}YF{sub 5}:1.0 at.% Tb{sup 3+}; 1.0 at.% Sm{sup 3+}, have been studied. Finally, the possible application of this single crystal as OSL dosimeter has been evaluated. (Author)

  9. Structural, Linear, and Nonlinear Optical and Mechanical Properties of New Organic L-Serine Crystal

    Directory of Open Access Journals (Sweden)

    K. Rajesh

    2014-01-01

    Full Text Available Nonlinear optical single crystal of organic amino acid L-Serine (LS was grown by slow evaporation technique. Solubility study of the compound was measured and metastable zone width was found. Single crystal X-ray diffraction study was carried out for the grown crystal. The linear and nonlinear optical properties of the crystal were confirmed by UV-Vis analysis and powder SHG tester. FT-IR spectrum was recorded and functional groups were analyzed. Vickers’ microhardness studies showed the mechanical strength of the grown crystal. Laser damage threshold value of the crystal was calculated. Photoconductivity studies reveal the conductivity of the crystal.

  10. Electron paramagnetic resonance and optical absorption of uranium ions diluted in CdF2 single crystals

    International Nuclear Information System (INIS)

    Pereira, J.J.C.R.

    1976-08-01

    The electron paramagnetic resonance (EPR) has been studied in conection with the optical absortion spectra of Uranium ions diluted in CdF 2 single crystals. Analyses of the EPR and optical absorption spectra obtained experimentally, and a comparison with known results in the isomorfic CaF 2 , SrF 2 and BaF 2 , allowed the identification of two paramagnetic centers associated with Uranium ions. These are the U(2+) ion in cubic symmetry having the triplet γ 5 as ground state, and the U(3+) ion in cubic symmetry having the dublet γ 6 as ground state. (Author) [pt

  11. Developments of a bonding technique for optical materials by a surface activation method

    International Nuclear Information System (INIS)

    Sugiyama, Akira; Oda, Tomohiro; Abe, Tomoyuki; Kusunoki, Isao

    2007-01-01

    We have been developing a pair of sample holder used for optics in the surface activation bonding equipment. The holder can adjust the relative position of samples in the order of sub mm. To study the degree of dislocation appearing crystal surface activated by a fast atomic beam, irradiated sapphire crystals were examined by RBS, XPS, and AFM analysis. The heat treatment recovered the surface roughness of irradiated sapphire when the heating temperature reached at 1573 K. (author)

  12. Growth and characterization of Sm3+ doped cerium oxalate single crystals

    Directory of Open Access Journals (Sweden)

    Minu Mary C

    2016-07-01

    Full Text Available Single crystals of Sm3+ doped cerium oxalate decahydrate were synthesized using single diffusion gel technique and the conditions influencing the size, morphology, nucleation density and quality of the crystals were optimized. Highly transparent single crystals of average size 3 mm × 2 mm × 1 mm with well-defined hexagonal morphology were grown during a time period of two weeks. X-ray powder diffraction analysis revealed that the grown crystals crystallize in the monoclinic system with space group P21/c as identical with the pure cerium oxalate. The various functional groups of the oxalate ligand and the water of crystallization were identified by Fourier transform infrared spectroscopy. The photoluminescence spectrum of the Sm3+ doped cerium oxalate indicated that the Sm3+ ions are optically active in the cerium oxalate matrix. The crystal has a strong and efficient orange red emission with a wavelength peak at 595 nm and hence can be effectively used for optical amplification. Microhardness measurements of the crystal revealed that they belong to the soft material category.

  13. Optical and transport properties of single crystal rubrene: A theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lipeng [Division of Materials Science, Nanyang Technological University, Singapore 639798 (Singapore); Lu, Jing [Division of Materials Science, Nanyang Technological University, Singapore 639798 (Singapore); Faculty of Chemistry, Northeast Normal University, Changchun (China); Long, Guankui; Zheng, Fulu [Division of Materials Science, Nanyang Technological University, Singapore 639798 (Singapore); Zhang, Jingping [Faculty of Chemistry, Northeast Normal University, Changchun (China); Zhao, Yang, E-mail: YZhao@ntu.edu.sg [Division of Materials Science, Nanyang Technological University, Singapore 639798 (Singapore)

    2016-12-20

    Optical and charge transport properties of single crystal rubrene are investigated using the multi-mode Brownian oscillator (MBO) model, the charge hopping model with quantum nuclear tunneling, and the Munn–Silbey approach. The MBO model is adopted to calculate absorption and photoluminescence spectra, yielding results in excellent agreement with measurements. In addition, temperature dependence of zero phonon lines (ZPL) and phonon sidebands (PSBs) of absorption spectra is also examined using the MBO model, revealing a nearly linear dependence of line widths of the ZPL and the PSBs on temperature. Model parameters obtained from MBO fitting and TD-DFT computation are then utilized for hole mobility calculations. It is found that temperature dependence of the calculated mobility is in general agreement with measurements, exhibiting “band-like” transport behavior.

  14. Growth, structural, optical, thermal and mechanical studies on 4-Aminopyridinium monophthalate: A novel nonlinear optical crystal

    Science.gov (United States)

    Marudhu, G.; Krishnan, S.; Palanichamy, M.

    2016-03-01

    A novel nonlinear optical crystal of 4-Aminopyridinium monophthalate (4-APMP) was grown by slow evaporation technique using methanol as solvent. Single crystal X-ray diffraction analysis confirms that the grown crystal belongs to orthorhombic system. The presence of functional groups was qualitatively determined by FTIR analysis. The optical absorption studies reveal very low absorption in the entire visible region. The fluorescence emission spectrum shows the emission is in blue region. The thermal stability of the grown crystal is found to be around 197.2 °C. The SHG efficiency of the grown crystal is found to be 1.1 times than that of KDP crystals.

  15. Orientation dependence of dispersion and band gap of PIMNT single crystals

    Science.gov (United States)

    He, Chongjun; Chen, Hongbing; Wang, Jiming; Gu, Xiaorong; Wu, Tong; Liu, Youwen

    2018-01-01

    As piezoelectric materials, optical properties of xPb(In1/2Nb1/2)O3-(1-x-y)Pb(Mg1/3Nb2/3)O3-yPbTiO3 single crystals were not perfectly known. Here refractive indices and optical transmission of 0.25Pb(In1/2Nb1/2)O3-0.42Pb(Mg1/3Nb2/3)O3- 0.33PbTiO3 (PIMNT) single crystal are investigated after poled along different directions. Cauchy dispersion equations of the refractive indices were obtained by least square fitting, which can be used to calculate the refractive indices in the low absorption wavelength range. After poled along [011] direction, the optical transmission of PIMNT single crystal is more than 65% above 0.5 μm, which is much higher than that of [001] and [111] directions. Energy band gap was obtained from absorption coefficient.

  16. Hydrothermal growth of PbSO4 (Anglesite) single crystal

    International Nuclear Information System (INIS)

    Kikuta, Ko-ichi; Yoneta, Yasuhito; Yogo, Toshinobu; Hirano, Shin-ichi

    1994-01-01

    Hydrothermal growth of single crystals of PbSO 4 , which is known as a natural mineral called anglesite, was investigated. Lead nitrate and nitric acid solutions were found to be useful for the growth of angle-site on the basis of the experimental results on the dissolution behavior. Relatively large euhedral single crystals bound by {210} and {101} planes were successfully grown in 1.5 mol/kg Pb(NO 3 ) 2 at 400degC and 100 MPa. Optical characterization revealed that the grown anglesite crystals can be useful for scintillators material. (author)

  17. Characterisation of irradiation-induced defects in ZnO single crystals

    International Nuclear Information System (INIS)

    Prochazka, I; Cizek, J; Lukac, F; Melikhova, O; Valenta, J; Havranek, V; Anwand, W; Skuratov, V A; Strukova, T S

    2016-01-01

    Positron annihilation spectroscopy (PAS) combined with optical methods was employed for characterisation of defects in the hydrothermally grown ZnO single crystals irradiated by 167 MeV Xe 26+ ions to fluences ranged from 3×10 12 to 1×10 14 cm -2 . The positron lifetime (LT), Doppler broadening as well as slow-positron implantation spectroscopy (SPIS) techniques were involved. The ab-initio theoretical calculations were utilised for interpretation of LT results. The optical transmission and photoluminescence measurements were conducted, too. The virgin ZnO crystal exhibited a single component LT spectrum with a lifetime of 182 ps which is attributed to saturated positron trapping in Zn vacancies associated with hydrogen atoms unintentionally introduced into the crystal during the crystal growth. The Xe ion irradiated ZnO crystals have shown an additional component with a longer lifetime of ≈ 360 ps which comes from irradiation-induced larger defects equivalent in size to clusters of ≈10 to 12 vacancies. The concentrations of these clusters were estimated on the basis of combined LT and SPIS data. The PAS data were correlated with irradiation induced changes seen in the optical spectroscopy experiments. (paper)

  18. Characterisation of irradiation-induced defects in ZnO single crystals

    Science.gov (United States)

    Prochazka, I.; Cizek, J.; Lukac, F.; Melikhova, O.; Valenta, J.; Havranek, V.; Anwand, W.; Skuratov, V. A.; Strukova, T. S.

    2016-01-01

    Positron annihilation spectroscopy (PAS) combined with optical methods was employed for characterisation of defects in the hydrothermally grown ZnO single crystals irradiated by 167 MeV Xe26+ ions to fluences ranged from 3×1012 to 1×1014 cm-2. The positron lifetime (LT), Doppler broadening as well as slow-positron implantation spectroscopy (SPIS) techniques were involved. The ab-initio theoretical calculations were utilised for interpretation of LT results. The optical transmission and photoluminescence measurements were conducted, too. The virgin ZnO crystal exhibited a single component LT spectrum with a lifetime of 182 ps which is attributed to saturated positron trapping in Zn vacancies associated with hydrogen atoms unintentionally introduced into the crystal during the crystal growth. The Xe ion irradiated ZnO crystals have shown an additional component with a longer lifetime of ≈ 360 ps which comes from irradiation-induced larger defects equivalent in size to clusters of ≈10 to 12 vacancies. The concentrations of these clusters were estimated on the basis of combined LT and SPIS data. The PAS data were correlated with irradiation induced changes seen in the optical spectroscopy experiments.

  19. Electrically-pumped, broad-area, single-mode photonic crystal lasers.

    Science.gov (United States)

    Zhu, Lin; Chak, Philip; Poon, Joyce K S; DeRose, Guy A; Yariv, Amnon; Scherer, Axel

    2007-05-14

    Planar broad-area single-mode lasers, with modal widths of the order of tens of microns, are technologically important for high-power applications and improved coupling efficiency into optical fibers. They may also find new areas of applications in on-chip integration with devices that are of similar size scales, such as for spectroscopy in microfluidic chambers or optical signal processing with micro-electromechanical systems. An outstanding challenge is that broad-area lasers often require external means of control, such as injection-locking or a frequency/spatial filter to obtain single-mode operation. In this paper, we propose and demonstrate effective index-guided, large-area, edge-emitting photonic crystal lasers driven by pulsed electrical current injection at the optical telecommunication wavelength of 1550 nm. By suitable design of the photonic crystal lattice, our lasers operate in a single mode with a 1/e(2) modal width of 25 microm and a length of 600 microm.

  20. Measurement of AC electrical conductivity of single crystal Al2O3 during spallation-neutron irradiation

    International Nuclear Information System (INIS)

    Kennedy, J.C. III; Farnum, E.H.; Sommer, W.F.; Clinard, F.W. Jr.

    1993-01-01

    Samples of single crystal Al 2 O 3 , commonly known as sapphire, and polycrystalline Al 2 O 3 were irradiated with spallation neutrons at the Los Alamos Spallation Radiation Effects Facility (LASREF) under various temperature conditions and with a continuously applied alternating electric field. This paper describes the results of measurements on the sapphire samples. Neutron fluence and flux values are estimated values pending recovery and analysis of dosimetry packages. The conductivity increased approximately with the square root of the neutron flux at fluences less than 3 x 10 21 n/m 2 . The increase in conductivity reached saturated levels as high as 2 x 10 -2 (ohm-m) -1 at fluences as low as 2 x 10 22 n/m 2 . Frequency swept impedance measurements indicated a change in the electrical properties from capacitive to resistive behavior with increasing fluence

  1. Random photonic crystal optical memory

    International Nuclear Information System (INIS)

    Wirth Lima Jr, A; Sombra, A S B

    2012-01-01

    Currently, optical cross-connects working on wavelength division multiplexing systems are based on optical fiber delay lines buffering. We designed and analyzed a novel photonic crystal optical memory, which replaces the fiber delay lines of the current optical cross-connect buffer. Optical buffering systems based on random photonic crystal optical memory have similar behavior to the electronic buffering systems based on electronic RAM memory. In this paper, we show that OXCs working with optical buffering based on random photonic crystal optical memories provides better performance than the current optical cross-connects. (paper)

  2. Optical Microcavity: Sensing down to Single Molecules and Atoms

    Directory of Open Access Journals (Sweden)

    Shu-Yu Su

    2011-02-01

    Full Text Available This review article discusses fundamentals of dielectric, low-loss, optical micro-resonator sensing, including figures of merit and a variety of microcavity designs, and future perspectives in microcavity-based optical sensing. Resonance frequency and quality (Q factor are altered as a means of detecting a small system perturbation, resulting in realization of optical sensing of a small amount of sample materials, down to even single molecules. Sensitivity, Q factor, minimum detectable index change, noises (in sensor system components and microcavity system including environments, microcavity size, and mode volume are essential parameters to be considered for optical sensing applications. Whispering gallery mode, photonic crystal, and slot-type microcavities typically provide compact, high-quality optical resonance modes for optical sensing applications. Surface Bloch modes induced on photonic crystals are shown to be a promising candidate thanks to large field overlap with a sample and ultra-high-Q resonances. Quantum optics effects based on microcavity quantum electrodynamics (QED would provide novel single-photo-level detection of even single atoms and molecules via detection of doublet vacuum Rabi splitting peaks in strong coupling.

  3. Quadrupolar interactions in non-cubic crystal and related extra heat capacities. Possible effects on a sapphire bolometer

    Energy Technology Data Exchange (ETDEWEB)

    Bassou, M. [Tunis Univ. (Tunisia)]|[CEA/DSM/DRECAM/SPEC, Gif-wur-Yvette (France); Rotter, M. [Karlova Univ., Prague (Czech Republic)]|[CEA/DSM/DRECAM/SPEC, Gif-wur-Yvette (France); Bernier, M. [CEA/DSM/DRECAM/SPEC, Gif-wur-Yvette (France); Chapellier, M. [CEA/DSM/DRECAM/SPEC, Gif-wur-Yvette (France)

    1996-02-11

    It is shown that in a non-cubic crystal, the extra heat capacity due to quadrupolar interaction of nuclear spins >1/2 could be much bigger than the phonon heat capacity when the temperature decreases. The possible coupling between quadrupolar and phonon heat reservoir via paramagnetic impurities is stressed. A NMR experiment done on sapphire is presented with an evaluation of the coupling between the two reservoirs and its consequence on the performance of the bolometer. (orig.).

  4. Quadrupolar interactions in non-cubic crystal and related extra heat capacities. Possible effects on a sapphire bolometer

    International Nuclear Information System (INIS)

    Bassou, M.; Rotter, M.; Bernier, M.; Chapellier, M.

    1996-01-01

    It is shown that in a non-cubic crystal, the extra heat capacity due to quadrupolar interaction of nuclear spins >1/2 could be much bigger than the phonon heat capacity when the temperature decreases. The possible coupling between quadrupolar and phonon heat reservoir via paramagnetic impurities is stressed. A NMR experiment done on sapphire is presented with an evaluation of the coupling between the two reservoirs and its consequence on the performance of the bolometer. (orig.)

  5. Optical characterization of epitaxial single crystal CdTe thin films on Al{sub 2}O{sub 3} (0001) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Jovanovic, S.M.; Devenyi, G.A., E-mail: devenyga@mcmaster.ca; Jarvis, V.M.; Meinander, K.; Haapamaki, C.M.; Kuyanov, P.; Gerber, M.; LaPierre, R.R.; Preston, J.S.

    2014-11-03

    The optoelectronic properties of single crystal CdTe thin films were investigated by photoluminescence spectroscopy, photoreflectance spectroscopy and variable angle spectroscopic ellipsometry. The room temperature bandgap was measured to be 1.51 eV and was consistent between spectroscopic measurements and previously reported values. Breadth of bandgap emission was consistent with high quality material. Low temperature photoluminescence spectra indicated a dominant emission consistent with bound excitons. Emissions corresponding to self-compensation defects, doping and contaminants were not found. Variable angle spectroscopic ellipsometry measurements over the near-UV to infrared range demonstrated sharp resonance peaks. All spectroscopic measurements indicate high quality thin film material of comparable or better quality than bulk CdTe. - Highlights: • High quality epitaxial CdTe thin films were grown. • Two dimensional X-ray diffraction characterization confirmed single crystal material. • Photoluminescence indicated low defect density when compared to bulk single crystals. • Optical characterization indicated the presence of room temperature excitons.

  6. An optical, electro-optic and thermal characterisation of various organic crystals

    International Nuclear Information System (INIS)

    Lochran, Stephen

    1997-01-01

    The organic materials S - 3 - methyl - 5 - nitro - N - (1 - phenylethyl) - 2 - pyridinamine [3- methyl-MBANP] and S - N - methyl - 5 - nitro - N -(1 - phenylethyl) - 2 - pyridinamine [N- methyl-MBANP] belong to a family of compounds based on the 2-(α-methylbenzylamino)-5- nitropyridine molecule and were identified as promising nonlinear optical materials by the powder disk test. Large single crystals were grown from solution for N-methyl-MBANP, which crystallises in a monoclinic space group, and from the melt and solution for 3-methyl-MBANP which crystallises in an orthorhombic space group. Orthoscopic examination of N-methyl-MBANP revealed no dispersion of the dielectric axes unlike the parent molecule and the position of the dielectric axes was correlated with the molecular structure. Preparation of prisms from single crystals of both materials facilitated the measurement of refractive indices in the visible and the near infra-red. The values obtained were correlated with the crystal structure and a Sellmeier equation fitted to each of the dispersion curves. The nonlinear optical properties of both materials were evaluated by use of the Maker fringe technique and phase matched intensities. By means of these two methods, the full nonlinear d ij tensor was obtained for both materials at a fundamental wavelength of 1064nm. The linear electro-optic properties of N-methyl-MBANP were evaluated using a conoscopic experiment and correlated with the crystal structure together with the magnitude of all non-zero elements in the d ij tensor. Separately, the thermal properties of N-methylurea (NMU), 4-nitro-4'-methylbenzylidene aniline (NMBA) and Zinc TrisThiourea Sulfate (ZTS) were evaluated and all correlated with the crystal structure and bonding. (author)

  7. Growth and spectroscopic, thermodynamic and nonlinear optical studies of L-threonine phthalate crystal

    Science.gov (United States)

    Theras, J. Elberin Mary; Kalaivani, D.; Jayaraman, D.; Joseph, V.

    2015-10-01

    L-threonine phthalate (LTP) single crystal has been grown using a solution growth technique at room temperature. Single crystal X-ray diffraction analysis reveals that LTP crystallizes in monoclinic crystal system with space group C2/c. The optical absorption studies show that the crystal is transparent in the entire visible region with a cut-off wavelength 309 nm. The optical band gap is found to be 4.05 eV. The functional groups of the synthesized compound have been identified by FTIR spectral analysis. The functional groups present in the material were also confirmed by FT-RAMAN spectroscopy. Surface morphology and the presence of various elements were studied by SEM-EDAX analysis. The thermal stability of LTP single crystal has been analyzed by TGA/DTA studies. The thermodynamic parameters such as activation energy, entropy, enthalpy and Gibbs free energy were determined for the grown material using TG data and Coats-Redfern relation. Since the grown crystal is centrosymmetric, Z-Scan studies were carried out for analyzing the third order nonlinear optical property. The nonlinear absorption coefficient, nonlinear refractive index and susceptibility have been measured using Z-Scan technique.

  8. Polishing Sapphire Substrates by 355 nm Ultraviolet Laser

    Directory of Open Access Journals (Sweden)

    X. Wei

    2012-01-01

    Full Text Available This paper tries to investigate a novel polishing technology with high efficiency and nice surface quality for sapphire crystal that has high hardness, wear resistance, and chemical stability. A Q-switched 355 nm ultraviolet laser with nanosecond pulses was set up and used to polish sapphire substrate in different conditions in this paper. Surface roughness Ra of polished sapphire was measured with surface profiler, and the surface topography was observed with scanning electronic microscope. The effects of processing parameters as laser energy, pulse repetition rate, scanning speed, incident angle, scanning patterns, and initial surface conditions on surface roughness were analyzed.

  9. Growth and Characterization of Lithium Potassium Phthalate (LiKP) Single Crystals for Third Order Nonlinear Optical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Sivakumar, B.; Mohan, R. [Preidency College, Bangalore (India); Raj, S. Gokul [RR and Dr. SR Technical Univ., Avadi (India); Kumar, G. Ramesh [Anna Univ., Arni (India)

    2012-11-15

    Single crystals of lithium potassium phthalate (LiKP) were successfully grown from aqueous solution by solvent evaporation technique. The grown crystals were characterized by single crystal X-ray diffraction. The lithium potassium phthalate C{sub 16} H{sub 12} K Li{sub 3} O{sub 11} belongs to triclinic system with the following unit-cell dimensions at 298(2) K; a = 7.405(5) A; b = 9.878(5) A; c = 13.396(5) A; α = 71.778(5) .deg.; β = 87.300(5) .deg.; γ = 85.405(5) .deg.; having a space group P1. Mass spectrometric analysis provides the molecular weight of the compound and possible ways of fragmentations occurs in the compound. Thermal stability of the crystal was also studied by both simultaneous TGA/DTA analyses. The UV-Vis-NIR spectrum shows a good transparency in the whole of Visible and as well as in the near IR range. Third order nonlinear optical studies have also been studied by Z-scan technique. Nonlinear absorption and nonlinear refractive index were found out and the third order bulk susceptibility of compound was also estimated.

  10. Polarization singularities of optical fields caused by structural dislocations in crystals

    International Nuclear Information System (INIS)

    Savaryn, V; Vasylkiv, Yu; Krupych, O; Skab, I; Vlokh, R

    2013-01-01

    We analyze polarization singularities of optical beams that propagate through crystals possessing structural dislocations. We show that screw dislocations of crystalline structure can lead to the appearance of purely screw-type dislocations of light wavefronts. This can happen only in crystals that belong to trigonal and cubic systems. These polarization singularities will give rise to optical vortices with the topological charge equal to ±1, whenever a crystal sample is placed between crossed circular polarizers. We have also found that edge dislocations present in the cubic and trigonal crystals, with the Burgers vector perpendicular to the three-fold symmetry axes, can impose mixed screw-edge dislocations in the wavefronts of optical beams and generate singly charged optical vortices. The results of our analysis can be applied for detecting and identifying dislocations of different types available in crystals. (paper)

  11. Growth and optical characterizations on 3-aminophenol perchlorate (3-AMPP) crystal

    Energy Technology Data Exchange (ETDEWEB)

    Boopathi, K., E-mail: ramasamyp@ssn.edu.in; Ramasamy, P., E-mail: ramasamyp@ssn.edu.in [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam-603110 (India)

    2014-04-24

    A single crystal of organic nonlinear optical material 3-aminophenol perchlorate (3-AMP) was successfully grown by the slow evaporation solution method. Single-crystal X-ray diffractrometer was utilized to measure unit cell parameters and to confirm lattice parameter. 3-aminophenol perchlorate belongs to monoclinic space group P2{sub 1}. The optical transparency window in the UV-vis-NIR region is found to be good for nonlinear optical applications second harmonic studies were carried out. The second harmonic output intensity was tested using the Kurtz and Perry powder method and was found to be 1.1 times that of potassium dihydrogen phosphate (KDP)

  12. Optimizing Ti:Sapphire laser for quantitative biomedical imaging

    Science.gov (United States)

    James, Jeemol; Thomsen, Hanna; Hanstorp, Dag; Alemán Hérnandez, Felipe Ademir; Rothe, Sebastian; Enger, Jonas; Ericson, Marica B.

    2018-02-01

    Ti:Sapphire lasers are powerful tools in the field of scientific research and industry for a wide range of applications such as spectroscopic studies and microscopic imaging where tunable near-infrared light is required. To push the limits of the applicability of Ti:Sapphire lasers, fundamental understanding of the construction and operation is required. This paper presents two projects, (i) dealing with the building and characterization of custom built tunable narrow linewidth Ti:Sapphire laser for fundamental spectroscopy studies; and the second project (ii) the implementation of a fs-pulsed commercial Ti:Sapphire laser in an experimental multiphoton microscopy platform. For the narrow linewidth laser, a gold-plated diffraction grating with a Littrow geometry was implemented for highresolution wavelength selection. We demonstrate that the laser is tunable between 700 to 950 nm, operating in a pulsed mode with a repetition rate of 1 kHz and maximum average output power around 350 mW. The output linewidth was reduced from 6 GHz to 1.5 GHz by inserting an additional 6 mm thick etalon. The bandwidth was measured by means of a scanning Fabry Perot interferometer. Future work will focus on using a fs-pulsed commercial Ti:Sapphire laser (Tsunami, Spectra physics), operating at 80 MHz and maximum average output power around 1 W, for implementation in an experimental multiphoton microscopy set up dedicated for biomedical applications. Special focus will be on controlling pulse duration and dispersion in the optical components and biological tissue using pulse compression. Furthermore, time correlated analysis of the biological samples will be performed with the help of time correlated single photon counting module (SPCM, Becker&Hickl) which will give a novel dimension in quantitative biomedical imaging.

  13. Sapphire: Canada's Answer to Space-Based Surveillance of Orbital Objects

    Science.gov (United States)

    Maskell, P.; Oram, L.

    The Canadian Department of National Defence is in the process of developing the Canadian Space Surveillance System (CSSS) as the main focus of the Surveillance of Space (SofS) Project. The CSSS consists of two major elements: the Sapphire System and the Sensor System Operations Centre (SSOC). The space segment of the Sapphire System is comprised of the Sapphire Satellite - an autonomous spacecraft with an electro-optical payload which will act as a contributing sensor to the United States (US) Space Surveillance Network (SSN). It will operate in a circular, sunsynchronous orbit at an altitude of approximately 750 kilometers and image a minimum of 360 space objects daily in orbits ranging from 6,000 to 40,000 kilometers in altitude. The ground segment of the Sapphire System is composed of a Spacecraft Control Center (SCC), a Satellite Processing and Scheduling Facility (SPSF), and the Sapphire Simulator. The SPSF will be responsible for data transmission, reception, and processing while the SCC will serve to control and monitor the Sapphire Satellite. Surveillance data will be received from Sapphire through two ground stations. Following processing by the SPSF, the surveillance data will then be forwarded to the SSOC. The SSOC will function as the interface between the Sapphire System and the US Joint Space Operations Center (JSpOC). The JSpOC coordinates input from various sensors around the world, all of which are a part of the SSN. The SSOC will task the Sapphire System daily and provide surveillance data to the JSpOC for correlation with data from other SSN sensors. This will include orbital parameters required to predict future positions of objects to be tracked. The SSOC receives daily tasking instructions from the JSpOC to determine which objects the Sapphire spacecraft is required to observe. The advantage of this space-based sensor over ground-based telescopes is that weather and time of day are not factors affecting observation. Thus, space-based optical

  14. A multistep single-crystal-to-single-crystal bromodiacetylene dimerization

    Science.gov (United States)

    Hoheisel, Tobias N.; Schrettl, Stephen; Marty, Roman; Todorova, Tanya K.; Corminboeuf, Clémence; Sienkiewicz, Andrzej; Scopelliti, Rosario; Schweizer, W. Bernd; Frauenrath, Holger

    2013-04-01

    Packing constraints and precise placement of functional groups are the reason that organic molecules in the crystalline state often display unusual physical or chemical properties not observed in solution. Here we report a single-crystal-to-single-crystal dimerization of a bromodiacetylene that involves unusually large atom displacements as well as the cleavage and formation of several bonds. Density functional theory computations support a mechanism in which the dimerization is initiated by a [2 + 1] photocycloaddition favoured by the nature of carbon-carbon short contacts in the crystal structure. The reaction proceeded up to the theoretical degree of conversion without loss of crystallinity, and it was also performed on a preparative scale with good yield. Moreover, it represents the first synthetic pathway to (E)-1,2-dibromo-1,2-diethynylethenes, which could serve as synthetic intermediates for the preparation of molecular carbon scaffolds. Our findings both extend the scope of single-crystal-to-single-crystal reactions and highlight their potential as a synthetic tool for complex transformations.

  15. Distinct crystallinity and orientations of hydroxyapatite thin films deposited on C- and A-plane sapphire substrates

    Science.gov (United States)

    Akazawa, Housei; Ueno, Yuko

    2014-10-01

    We report how the crystallinity and orientation of hydroxyapatite (HAp) films deposited on sapphire substrates depend on the crystallographic planes. Both solid-phase crystallization of amorphous HAp films and crystallization during sputter deposition at elevated temperatures were examined. The low-temperature epitaxial phase on C-plane sapphire substrates has c-axis orientated HAp crystals regardless of the crystallization route, whereas the preferred orientation switches to the (310) direction at higher temperatures. Only the symmetric stretching mode (ν1) of PO43- units appears in the Raman scattering spectra, confirming well-ordered crystalline domains. In contrast, HAp crystals grown on A-plane sapphire substrates are always oriented toward random orientations. Exhibiting all vibrational modes (ν1, ν3, and ν4) of PO43- units in the Raman scattering spectra reflects random orientation, violating the Raman selection rule. If we assume that Raman intensities of PO43- units represent the crystallinity of HAp films, crystallization terminating the surface with the C-plane is hindered by the presence of excess H2O and OH species in the film, whereas crystallization at random orientations on the A-plane sapphire is rather promoted by these species. Such contrasting behaviors between C-plane and A-plane substrates will reflect surface-plane dependent creation of crystalline seeds and eventually determine the orientation of resulting HAp films.

  16. Metal Halide Perovskite Single Crystals: From Growth Process to Application

    Directory of Open Access Journals (Sweden)

    Shuigen Li

    2018-05-01

    Full Text Available As a strong competitor in the field of optoelectronic applications, organic-inorganic metal hybrid perovskites have been paid much attention because of their superior characteristics, which include broad absorption from visible to near-infrared region, tunable optical and electronic properties, high charge mobility, long exciton diffusion length and carrier recombination lifetime, etc. It is noted that perovskite single crystals show remarkably low trap-state densities and long carrier diffusion lengths, which are even comparable with the best photovoltaic-quality silicon, and thus are expected to provide better optoelectronic performance. This paper reviews the recent development of crystal growth in single-, mixed-organic-cation and fully inorganic halide perovskite single crystals, in particular the solution approach. Furthermore, the application of metal hybrid perovskite single crystals and future perspectives are also highlighted.

  17. A Century of Sapphire Crystal Growth

    Science.gov (United States)

    2004-05-17

    should be aware that notwithstanding any other provision of law , no person shall be subject to a penalty for failing to comply with a collection of...and ruby were oxides of the elements aluminum and silicon.1 In 1817, J. L. Gay- Lussac found that pure aluminum oxide (also called alumina) could...thought to consist of Al2O3 and SiO2 •1817: Gay- Lussac : •1840: Rose: Found SiO2 in sapphire is from agate mortar used for grinding •1837-72: Gaudin

  18. High Temperature Testing with Sapphire Fiber White-Light Michelson Interferometers

    Science.gov (United States)

    Barnes, A.; Pedrazzani, J.; May, R.; Murphy, K.; Tran, T.; Coate, J.

    1996-01-01

    In the design of new aerospace materials, developmental testing is conducted to characterize the behavior of the material under severe environmental conditions of high stress, temperature, and vibration. But to test these materials under extreme conditions requires sensors that can perform in harsh environments. Current sensors can only monitor high temperature test samples using long throw instrumentation, but this is inherently less accurate than a surface mounted sensor, and provides no means for fabrication process monitoring. A promising alternative is the use of sapphire optical fiber sensors. Sapphire is an incredibly rugged material, being extremely hard (9 mhos), chemically inert, and having a melting temperature (over 2000 C). Additionally, there is a extensive background of optical fiber sensors upon which to draw for sapphire sensor configurations.

  19. Developments of a bonding technique for optical materials by a surface activation method

    International Nuclear Information System (INIS)

    Sugiyama, Akira; Oda, Tomohiro; Abe, Tomoyuki; Kusunoki, Isao

    2005-01-01

    We started developing the laser crystal bounding by the surface activation method which can splice crystals together without using hydrogen bonding. For the surface activation, neutral argon beams were used for irradiation of specimens. In the bonding trials with sapphire crystals, we recognized possibility of the bonding method for optical elements. (author)

  20. Single-Cycle Terahertz Pulse Generation from OH1 Crystal via Cherenkov Phase Matching

    Science.gov (United States)

    Uchida, Hirohisa; Oota, Kengo; Okimura, Koutarou; Kawase, Kodo; Takeya, Kei

    2018-06-01

    OH1 crystal is an organic nonlinear optical crystal with a large nonlinear optical constant. However, it has dispersion of refractive indices in the terahertz (THz) frequency. This limits the frequencies that satisfy the phase matching conditions for THz wave generation. In this study, we addressed the phase matching conditions for THz wave generation by combining an OH1 crystal with prism-coupled Cherenkov phase matching. We observed the generation of single-cycle THz pulses with a spectrum covering a frequency range of 3 THz. These results prove that combining prism-coupled Cherenkov phase matching with nonlinear optical crystals yields a THz wave generation method that is insusceptible to crystal dispersion.

  1. Growth of HfO{sub x} thin films by reactive molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institut fuer Materialwissenschaft, TU Darmstadt (Germany)

    2008-07-01

    Thin films of hafnium oxide were grown on single crystal r-cut and c-cut sapphire by reactive molecular beam epitaxy. The conditions for the growth of single oriented hafnium oxide thin films have been established. Hafnium oxide thin films were characterized by X-ray diffraction and optical absorption measurements. It was found that hafnium oxide thin films grown on r-cut sapphire were (00l) oriented whereas, on c-cut sapphire, hafnium oxide films showed different orientations depending on the growth temperature and oxidation conditions. The hafnium oxide films grown at higher temperature and under strong oxidation conditions yielded (001) oriented films on c-cut sapphire whereas slightly weaker oxidation condition leads to (111) oriented hafnium oxide films. The bandgap deducted from optical absorption measurement carried out on hafnium oxide films grown under optimized conditions agreed well with the values reported in literature. A range of oxygen deficient thin films of hafnium oxide were also grown on single crystal sapphire substrates in order to investigate the effect of oxygen vacancies on dielectric properties of hafnium oxide. The oxygen deficient thin films of hafnium oxide show a decrease in bandgap with increase in oxygen deficiency.

  2. Crystal Growth Technology

    Science.gov (United States)

    Scheel, Hans J.; Fukuda, Tsuguo

    2004-06-01

    This volume deals with the technologies of crystal fabrication, of crystal machining, and of epilayer production and is the first book on industrial and scientific aspects of crystal and layer production. The major industrial crystals are treated: Si, GaAs, GaP, InP, CdTe, sapphire, oxide and halide scintillator crystals, crystals for optical, piezoelectric and microwave applications and more. Contains 29 contributions from leading crystal technologists covering the following topics: General aspects of crystal growth technology Silicon Compound semiconductors Oxides and halides Crystal machining Epitaxy and layer deposition Scientific and technological problems of production and machining of industrial crystals are discussed by top experts, most of them from the major growth industries and crystal growth centers. In addition, it will be useful for the users of crystals, for teachers and graduate students in materials sciences, in electronic and other functional materials, chemical and metallurgical engineering, micro-and optoelectronics including nanotechnology, mechanical engineering and precision-machining, microtechnology, and in solid-state sciences.

  3. Synthesis, growth, and structural, optical, mechanical, electrical properties of a new inorganic nonlinear optical crystal: Sodium manganese tetrachloride (SMTC

    Directory of Open Access Journals (Sweden)

    M. Packiya raj

    2017-01-01

    Full Text Available A new inorganic nonlinear optical single crystal of sodium manganese tetrachloride (SMTC has been successfully grown from aqueous solution using the slow evaporation technique at room temperature. The crystals obtained using the aforementioned method were characterized using different techniques. The crystalline nature of the as-grown crystal of SMTC was analyzed using powder X-ray diffraction. Single-crystal X-ray diffraction revealed that the crystal belongs to an orthorhombic system with non-centrosymmetric space group Pbam. The optical transmission study of the SMTC crystal revealed high transmittance in the entire UV–vis region, and the lower cut-off wavelength was determined to be 240 nm. The mechanical strength of the as-grown crystal was estimated using the Vickers microhardness test. The second harmonic generation (SHG efficiency of the crystal was measured using Kurtz's powder technique, which indicated that the crystal has a nonlinear optical (NLO efficiency that is 1.32 times greater than that of KDP. The dielectric constant and dielectric loss of the compound were measured at different temperatures with varying frequencies. The photoconductivity study confirmed that the title compound possesses a negative photoconducting nature. The growth mechanism and surface features of the as-grown crystals were investigated using chemical etching analysis.

  4. Development of frequency tunable Ti:sapphire laser and dye laser pumped by a pulsed Nd:YAG laser

    International Nuclear Information System (INIS)

    Yi, Jong Hoon; Horn, Roland; Wendt, K.

    2001-01-01

    We investigated lasing characteristics of two kinds of tunable laser, liquid dye laser and solid Ti:sapphire crystal laser, pumped by high pulse repetition rate Nd:YAG laser. Dye laser showed drastically reduced pulsewidth compared with that of pump laser and it also contained large amount of amplified spontaneous emission. Ti:sapphire laser showed also reduced pulsewidth. But, the laser conversion pump laser and Ti:sapphire laser pulse, we used a Brewster-cut Pockel's cell for Q-switching. The laser was frequency doubled by a type I BBO crystal outside of the cavity.

  5. Crystal growth and properties of novel organic nonlinear optical crystals of 4-Nitrophenol urea

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, M. Krishna, E-mail: krishnamohan.m@ktr.srmuniv.ac.in; Ponnusamy, S.; Muthamizhchelvan, C.

    2017-07-01

    Single crystals of 4-Nitrophenol urea have been grown from water using slow evaporation technique at constant temperature, with the vision to improve the properties of the crystals. The unit cell parameters of the grown crystals were determined by single crystal and powder X-Ray diffraction. FTIR studies reveals the presence of different vibrational bands. The Optical studies confirmed that the crystal is transparent up to 360 nm .TGA and DSC studies were carried out to understand the thermal behavior of crystals. The SHG studies show the suitability of the crystals for NLO applications. The etching studies were carried out to study the behavior of the crystals under different conditions.These studies reveal that the crystals of 4-Nitrophenol urea are suitable for device applications. - Highlights: • 4-Nitrophenol urea crystals of dimensions 14 mm × 1 mm were grown. • UV–Visible studies indicate the crystal is transparent in the region of 370–800 nm. • Thermal studies show the crystal starts decomposing at 170 °C. • SHG studies indicate that the crystals have NLO efficiency 3.5 times that of KDP.

  6. Controllable laser thermal cleavage of sapphire wafers

    Science.gov (United States)

    Xu, Jiayu; Hu, Hong; Zhuang, Changhui; Ma, Guodong; Han, Junlong; Lei, Yulin

    2018-03-01

    Laser processing of substrates for light-emitting diodes (LEDs) offers advantages over other processing techniques and is therefore an active research area in both industrial and academic sectors. The processing of sapphire wafers is problematic because sapphire is a hard and brittle material. Semiconductor laser scribing processing suffers certain disadvantages that have yet to be overcome, thereby necessitating further investigation. In this work, a platform for controllable laser thermal cleavage was constructed. A sapphire LED wafer was modeled using the finite element method to simulate the thermal and stress distributions under different conditions. A guide groove cut by laser ablation before the cleavage process was observed to guide the crack extension and avoid deviation. The surface and cross section of sapphire wafers processed using controllable laser thermal cleavage were characterized by scanning electron microscopy and optical microscopy, and their morphology was compared to that of wafers processed using stealth dicing. The differences in luminous efficiency between substrates prepared using these two processing methods are explained.

  7. Characterization of CuCl quantum dots grown in NaCl single crystals via optical measurements, X-ray diffraction, and transmission electron microscopy

    Science.gov (United States)

    Miyajima, Kensuke; Akatsu, Tatsuro; Itoh, Ken

    2018-05-01

    We evaluated the crystal size, shape, and alignment of the lattice planes of CuCl quantum dots (QDs) embedded in NaCl single crystals by optical measurements, X-ray diffraction (XRD) patterns, and transmission electron microscopy (TEM). We obtained, for the first time, an XRD pattern and TEM images for CuCl QDs in NaCl crystals. The XRD pattern showed that the lattice planes of the CuCl QDs were parallel to those of the NaCl crystals. In addition, the size of the QDs was estimated from the diffraction width. It was apparent from the TEM images that almost all CuCl QDs were polygonal, although some cubic QDs were present. The mean size and size distribution of the QDs were also obtained. The dot size obtained from optical measurements, XRD, and TEM image were almost consistent. Our new findings can help to reveal the growth mechanism of semiconductor QDs embedded in a crystallite matrix. In addition, this work will play an important role in progressing the study of optical phenomena originating from assembled semiconductor QDs.

  8. Mixed garnet laser crystals for water vapour DIAL transmitter

    Science.gov (United States)

    Treichel, Rainer; Czeranowsky, Christoph; Ileri, Bilge; Petermann, Klaus; Huber, Günter

    2017-11-01

    There are more or less well established technologies such as the optical-parametric-oscillator (OPO), the Raman-laser, and the Ti-Sapphire laser, which are able to emit laser light in the region of the water vapour absorption lines. For WALES the regions of about 935 nm, 942 nm, and 944 nm have been identified as the most suitable wavelength ranges. However, each of these laser designs is highly sophisticated. Current baseline for WALES is the Ti-Sapphire laser. A fourth possibility to achieve these wavelength ranges is to shift the groundstate laser lines (938 nm and 946 nm) of the Nd:YAG laser by replacing Aluminium and Yttrium by other rare earth elements. Changes of the host lattice characteristics lead to a shift of the upper and lower laser levels. These modified crystals are summarized under the name of "Mixed Garnet" crystals. Only the Mixed Garnet lasers can be pumped directly with diode laser and use a direct approach to generate the required laser pulses without frequency conversion. Therefore no additional non-linear crystals are needed and a higher electric to optical efficiency is expected as well as single frequency operation using spectral tuning elements like etalons. Such lasers have the great potential to fulfil the requirements and to become the preferred transmitter concept for WALES as well as for follow up missions. Within a ESA study several crystal compositions have been grown, spectrally characterised and analysed. Absorbed space radiation energy in the crystal lattice causes colour centres, which can reabsorb the pump and laser wavelength and consequently reduce the laser gain considerably. Co-dopants such as Chromium and Cerium are able to suppress the colour centres and are candidates for effective radiation hardening. The results of the crystal tuning, the co-doping with different radiation hardeners and the radiation tests will be presented. There applicability for a space based water vapour DIAL transmitter will be discussed.

  9. A confocal optical microscope for detection of single impurities in a bulk crystal at cryogenic temperatures.

    Science.gov (United States)

    Karlsson, Jenny; Rippe, Lars; Kröll, Stefan

    2016-03-01

    A compact sample-scanning confocal optical microscope for detection of single impurities below the surface of a bulk crystal at cryogenic temperatures is described. The sample, lens, and scanners are mounted inside a helium bath cryostat and have a footprint of only 19 × 19 mm. Wide field imaging and confocal imaging using a Blu-ray lens immersed in liquid helium are demonstrated with excitation at 370 nm. A spatial resolution of 300 nm and a detection efficiency of 1.6% were achieved.

  10. Theoretical studies of the optical and EPR spectra for VO^{2+} in Na_3C_6H_5O_7·2H_2O single crystal

    Directory of Open Access Journals (Sweden)

    Ch.-Y. Li

    2015-06-01

    Full Text Available On the basis of the perturbation formulas for a d^1 configuration ion in a tetragonal crystal field, the three optical absorption bands and electron paramagnetic resonance (EPR parameters (g factors g_i and hyperfine structure constants A_i for i = || and ⊥, respectively of VO^{2+} in Na_3C_6H_5O_7·2H_2O (TSCD single crystals were studied using the perturbation theory method. By simulating the calculated optical and EPR spectra to the observed values, local structure parameters and negative signs of the hyperfine structure constants A_i of the octahedral (VO_6^{8-} cluster in TSCD single crystal can be obtained.

  11. Gold wetting effects on sapphire irradiated with GeV uranium ions

    International Nuclear Information System (INIS)

    Ramos, S.M.M.

    1997-01-01

    Single crystals of α-Al 2 O 3 were irradiated with 238 U ions using two different energies: 3.4 MeV/u and 1.7 MeV/u. The irradiations were performed at a temperature of ∼80 K, with fluences ranging from 1.2 x 10 12 to 2.5 x 10 12 ions cm -2 . After irradiation, thin gold films were deposited on the sapphire surfaces by using a sputtering method. Subsequent annealing in air at a temperature of 723 and 923 K were applied to investigate the influence of the pre-damage on the adhesion of the gold layer on the sapphire surface. Rutherford backscattering analysis and scanning electron microscopy performed in both virgin and irradiated areas, show that the pre-irradiation damage inhibits the gold film of breaking up into islands after annealing. A wetting effect, which could depend on the damage morphology, is clearly observed. (orig.)

  12. Growth and characterization of polar and nonpolar ZnO film grown on sapphire substrates by using atomic layer deposition

    International Nuclear Information System (INIS)

    Kim, Ki-Wook; Son, Hyo-Soo; Choi, Nak-Jung; Kim, Jihoon; Lee, Sung-Nam

    2013-01-01

    We investigated the electrical and the optical properties of polar and nonpolar ZnO films grown on sapphire substrates with different crystallographic planes. High resolution X-ray results revealed that polar c-plane (0001), nonpolar m-plane (10-10) and a-plane (11-20) ZnO thin films were grown on c-plane, m- and r-sapphire substrates by atomic layer deposition, respectively. Compared with the c-plane ZnO film, nonpolar m-plane and a-plane ZnO films showed smaller surface roughness and anisotropic surface structures. Regardless of ZnO crystal planes, room temperature photoluminescence spectra represented two emissions which consisted of the near bandedge (∼ 380 nm) and the deep level emission (∼ 500 nm). The a-plane ZnO films represented better optical and electrical properties than c-plane ZnO, while m-plane ZnO films exhibited poorer optical and electrical properties than c-plane ZnO. - Highlights: • Growth and characterization of a-, c- and m-plane ZnO film by atomic layer deposition. • The a-plane ZnO represented better optical and electrical properties than c-plane ZnO. • The m-plane ZnO exhibited poorer optical and electrical properties than c-plane ZnO

  13. CH3NH3PbCl3 Single Crystals: Inverse Temperature Crystallization and Visible-Blind UV-Photodetector

    KAUST Repository

    Maculan, Giacomo

    2015-09-02

    Single crystals of hybrid perovskites have shown remarkably improved physical properties compared to their polycrystalline film counterparts, underscoring their importance in the further development of advanced semiconductor devices. Here we present a new method of sizeable CH3NH3PbCl3 single crystal growth based on retrograde solubility behavior of hybrid perovskites. We show, for the first time, the energy band structure, charge-carrier recombination and transport properties of single crystal CH3NH3PbCl3. The chloride-based perovskite crystals exhibit trap-state density, charge carriers concentration, mobility and diffusion length comparable with the best quality crystals of methylammonium lead iodide or bromide perovskites reported so far. The high quality of the crystal along with its suitable optical bandgap enabled us to design and build an efficient visible-blind UV-photodetector, demonstrating the potential of this material to be employed in optoelectronic applications.

  14. Investigations on the nucleation kinetics of γ-glycine single crystal

    International Nuclear Information System (INIS)

    Yogambal, C.; Rajan Babu, D.; Ezhil Vizhi, R.

    2014-01-01

    Single crystals of γ-glycine were grown by slow evaporation technique. The crystalline system was confirmed by single crystal X-ray diffraction analysis. The optical absorption study has shown that the grown crystal possesses lower cut-off wavelength. Solubility and metastable zone width were estimated for different temperatures. The induction period of title compound was determined by varying the temperature and concentration. Nucleation parameters such as Gibbs volume free energy change (ΔG v ), interfacial tension (γ), critical free energy change of the nucleus (ΔG ⁎ ), nucleation rate (J), number of molecules in the critical nucleus (i ⁎ ) have been calculated for the aqueous solution grown γ-glycine single crystals. The second harmonic generation (SHG) of γ-glycine was confirmed by Q-switched Nd:YAG laser technique

  15. Comments on the paper: 'Optical reflectance, optical refractive index and optical conductivity measurements of nonlinear optics for L-aspartic acid nickel chloride single crystal'

    Science.gov (United States)

    Srinivasan, Bikshandarkoil R.; Naik, Suvidha G.; Dhavskar, Kiran T.

    2016-02-01

    We argue that the 'L-aspartic acid nickel chloride' crystal reported by the authors of the title paper (Optics Communications, 291 (2013) 304-308) is actually the well-known diaqua(L-aspartato)nickel(II) hydrate crystal.

  16. Experimental and density functional theory (DFT): A dual approach to probe the key properties of creatininium L-tartrate monohydrate single crystal for nonlinear optical applications

    Science.gov (United States)

    Thirumurugan, R.; Babu, B.; Anitha, K.; Chandrasekaran, J.

    2017-12-01

    A novel organic nonlinear optical (NLO) material, creatininium L-tartrate monohydrate (CTM) was synthesized and it was grown as single crystals with optical quality. 1H and 13C NMR spectral studies were performed and molecular structure of synthesized CTM compound was confirmed. Single crystal X-ray diffraction (SXRD) analysis confirmed that CTM was crystallized in orthorhombic system with non-centrosymmetric (NCS), P212121, space group. The grown crystal exhibited admirable properties such as second harmonic generation efficiency (SHG) (1.9 times KDP), and high laser damage threshold (LDT) value of 3.7 GW cm-2. CTM crystal displayed high transparency (∼60%) in the visible and near-IR region with low cut-off wavelength at 249 nm. Photoluminescence study confirmed blue wavelength emission (∼463 nm) of grown crystal. Thermal and mechanical behaviours have been successfully analysed for grown crystals. The dielectric studies were carried out for grown crystal as a function of frequencies at different temperatures. Hirshfeld surface and fingerprint plots provided the percentage of individual interactions contributed by each atom. Moreover, density functional theory (DFT) calculations have been employed to probe the frontier molecular orbitals (FMOs) and first hyperpolarizability (β) analysis of the optimized CTM structure. These results validated CTM as a suitable NLO candidate and were discussed in this work.

  17. Growth, spectral, thermal, laser damage threshold, microhardness, dielectric, linear and nonlinear optical properties of an organic single crystal: L-phenylalanine DL-mandelic acid

    Energy Technology Data Exchange (ETDEWEB)

    Jayaprakash, P. [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India); Peer Mohamed, M. [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India); Department of Physics, C. Abdul Hakeem College, Melvisharam 632 509, Tamil Nadu (India); Krishnan, P. [Department of Physics, St. Joseph’s College of Engineering, Chennai 600 119, Tamil Nadu (India); Nageshwari, M.; Mani, G. [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India); Lydia Caroline, M., E-mail: lydiacaroline2006@yahoo.co.in [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604 407, Tamil Nadu (India)

    2016-12-15

    Single crystals of L-phenylalanine dl-mandelic acid [C{sub 9}H{sub 11}NO{sub 2}. C{sub 8}H{sub 8}O{sub 3}], have been grown by the slow evaporation technique at room temperature using aqueous solution. The single crystal XRD study confirms monoclinic system for the grown crystal. The functional groups present in the grown crystal have been identified by FTIR and FT-Raman analyses. The optical absorption studies show that the crystal is transparent in the visible region with a lower cut-off wavelength of 257 nm and the optical band gap energy E{sub g} is determined to be 4.62 eV. The Kurtz powder second harmonic generation was confirmed using Nd:YAG laser with fundamental wavelength of 1064 nm. Further, the thermal studies confirmed no weight loss up to 150°C for the as-grown crystal. The photoluminescence spectrum exhibited three peaks (414 nm, 519 nm, 568 nm) due to the donation of protons from carboxylic acid to amino group. Laser damage threshold value was found to be 4.98 GW/cm{sup 2}. The Vickers microhardness test was carried out on the grown crystals and there by Vickers hardness number (H{sub v}), work hardening coefficient (n), yield strength (σ{sub y}), stiffness constant C{sub 11} were evaluated. The dielectric behavior of the crystal has been determined in the frequency range 50 Hz–5 MHz at various temperatures.

  18. Crystal structure and optical properties of silver nanorings

    Science.gov (United States)

    Zhou, Li; Fu, Xiao-Feng; Yu, Liao; Zhang, Xian; Yu, Xue-Feng; Hao, Zhong-Hua

    2009-04-01

    We report the polyol synthesis and crystal structure characterization of silver nanorings, which have perfect circular shape, smooth surface, and elliptical wire cross-section. The characterization results show that the silver nanorings have well-defined crystal of singly twinned along the whole ring. The spatial distribution of the scattering of a silver nanoring with slanted incidence reveals the unique focus effect of the nanoring, and the focus scattering varies with the incident wavelength. The silver nanorings with perfect geometry and well-defined crystal have potential applications in nanoscaled photonics, plasmonic devices, and optical manipulation.

  19. Single phase semipolar (11 anti 22) GaN on (10 anti 10) sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Ploch, S.; Stellmach, J.; Schwaner, T.; Frentrup, M.; Wernicke, T.; Pristovsek, M.; Kneissl, M. [Institute of Solid States Physics, (Germany); Park, J.B.; Niermann, T.; Lehmann, M. [Institute of Optics and Atomic Physics, TU Berlin, Hardenbergstr. 36, 10623 Berlin (Germany)

    2011-07-01

    InGaN quantum well based light emitters grown on (0001) GaN suffer from poor quantum efficiencies with increasing indium mole fraction due to strong polarization fields along the polar crystal orientation. This effect can be greatly reduced by growing on semi- and non-polar GaN orientations. Semipolar (11 anti 22) GaN layers were deposited by metalorganic vapour phase epitaxy on (10 anti 10) sapphire. After sapphire substrate nitridation at 1000 C, a GaN nucleation layer was deposited at high temperature, followed by the deposition of 1.5 nm thick GaN buffer layers. The samples show predominantly (11 anti 22) orientation with a small fraction of (10 anti 13) oriented domains. With increasing nitridation layer thickness the (10 anti 13) phase is suppressed leading to a very smooth surface morphology (rms roughness < 4nm). PL measurements show dominant basel plane stacking fault (BSF) I{sub 1} luminescence without any other defects. Transmission electron microscopy measurements reveal a high BSF density. The FWHM of the X-ray diffraction rocking curve measurements of the (1122) reflection decreases to 1193 arcsec and 739 arcsec along [1 anti 100] and [11 anti 23] respectively with increasing nucleation temperature. Using high temperature nucleation smooth and homogeneous (11 anti 22) phase GaN layers have been obtained.

  20. Growth, and magnetic study of Sm0.4Er0.6FeO3 single crystal grown by optical floating zone technique

    Science.gov (United States)

    Wu, Anhua; Zhao, Xiangyang; Man, Peiwen; Su, Liangbi; Kalashnikova, A. M.; Pisarev, R. V.

    2018-03-01

    Sm0.4Er0.6FeO3 single crystals were successfully grown by optical floating zone method; high quality samples with various orientations were manufactured. Based on these samples, Magnetic property of Sm0.4Er0.6FeO3 single crystals were investigated systemically by means of the temperature dependence of magnetization. It indicated that compositional variations not only alter the spin reorientation temperature, but also the compensation temperature of the orthoferrites. Unlike single rare earth orthoferrites, the reversal transition temperature point of Sm0.4Er0.6FeO3 increases as magnetic field increases, which is positive for designing novel spin switching or magnetic sensor device.

  1. Optical spectra and lattice dynamics of molecular crystals

    CERN Document Server

    Zhizhin, GN

    1995-01-01

    The current volume is a single topic volume on the optical spectra and lattice dynamics of molecular crystals. The book is divided into two parts. Part I covers both the theoretical and experimental investigations of organic crystals. Part II deals with the investigation of the structure, phase transitions and reorientational motion of molecules in organic crystals. In addition appendices are given which provide the parameters for the calculation of the lattice dynamics of molecular crystals, procedures for the calculation of frequency eigenvectors of utilizing computers, and the frequencies and eigenvectors of lattice modes for several organic crystals. Quite a large amount of Russian literature is cited, some of which has previously not been available to scientists in the West.

  2. Czochralski growth and optical properties of Li 6Gd 1-xEu x(BO 3) 3 ( x=0-1) single crystals

    Science.gov (United States)

    Yavetskiy, R. P.; Dolzhenkova, E. F.; Dubovik, M. F.; Korshikova, T. I.; Tolmachev, A. V.

    2005-04-01

    It was shown that a continuous series of Li 6Gd 1-xEu x(BO 3) 3 solid solutions exist within the whole concentration range ( x=0-1). Li 6Gd 1-xEu x(BO 3) 3 ( x=0-0.03; 1) single crystals up to 25 mm in length and up to 20 mm in diameter have been grown by the Czochralski method. The structural perfection of the crystals has been estimated from etch patterns and XPA analysis results. The optical absorption and thermally stimulated luminescence of the grown crystals has been studied.

  3. Young's Modulus of Single-Crystal Fullerene C Nanotubes

    Directory of Open Access Journals (Sweden)

    Tokushi Kizuka

    2012-01-01

    Full Text Available We performed bending tests on single-crystal nanotubes composed of fullerene C70 molecules by in situ transmission electron microscopy with measurements of loading forces by an optical deflection method. The nanotubes with the outer diameters of 270–470 nm were bent using simple-beam and cantilever-beam loading by the piezomanipulation of silicon nanotips. Young's modulus of the nanotubes increased from 61 GPa to 110 GPa as the outer diameter decreased from 470 nm to 270 nm. Young's modulus was estimated to be 66% of that of single-crystal C60 nanotubes of the same outer diameter.

  4. Optical Trapping of Ion Coulomb Crystals

    Science.gov (United States)

    Schmidt, Julian; Lambrecht, Alexander; Weckesser, Pascal; Debatin, Markus; Karpa, Leon; Schaetz, Tobias

    2018-04-01

    The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

  5. Growth and characterization of air annealing Tb-doped YAG:Ce single crystal for white-light-emitting diode

    International Nuclear Information System (INIS)

    Gong, Maogao; Xiang, Weidong; Liang, Xiaojuan; Zhong, Jiasong; Chen, Daqin; Huang, Jun; Gu, Guorui; Yang, Cheng; Xiang, Run

    2015-01-01

    Highlights: • We report preparation of transparent Ce,Tb:YAG single crystal by Czochralski method. • The effect of annealing on Ce,Tb:YAG single crystal had been investigated. • The Ce,Tb:YAG single crystal after annealing exhibited better optical performance. • The Ce,Tb:YAG single crystal could be used as an ideal candidate for WLED. - Abstract: We report the preparation of transparent Ce and Tb co-doped Y 3 Al 5 O 12 single crystal by the Czochralski method. The characterization of the resulting single crystal was accomplished by using X-ray powder diffractometer, scanning electron microscopy and energy dispersive X-ray spectroscopy. Absorption peak of the single crystal at about 460 nm has been obtained from ultraviolet–visible absorption spectrometer and their intensity is changed with different annealing condition. Its optical properties also have been investigated using fluorescence spectrometer. What’s more, its photoelectric parameters were studied by LED fast spectrometer. The constructed single crystal based white-light-emitting diode exhibits a high luminous efficiency of 140.89 lm/W, and a correlated color temperature of 4176 K as well as a color rendering index of 56.7, which reveal the prominent feasibility of the present single crystal material in white-light-emitting diode application

  6. Growth and characterization of air annealing Tb-doped YAG:Ce single crystal for white-light-emitting diode

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Maogao [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035 (China); Xiang, Weidong, E-mail: xiangweidong001@126.com [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035 (China); Liang, Xiaojuan [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035 (China); Zhong, Jiasong; Chen, Daqin [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Huang, Jun; Gu, Guorui; Yang, Cheng; Xiang, Run [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035 (China)

    2015-08-05

    Highlights: • We report preparation of transparent Ce,Tb:YAG single crystal by Czochralski method. • The effect of annealing on Ce,Tb:YAG single crystal had been investigated. • The Ce,Tb:YAG single crystal after annealing exhibited better optical performance. • The Ce,Tb:YAG single crystal could be used as an ideal candidate for WLED. - Abstract: We report the preparation of transparent Ce and Tb co-doped Y{sub 3}Al{sub 5}O{sub 12} single crystal by the Czochralski method. The characterization of the resulting single crystal was accomplished by using X-ray powder diffractometer, scanning electron microscopy and energy dispersive X-ray spectroscopy. Absorption peak of the single crystal at about 460 nm has been obtained from ultraviolet–visible absorption spectrometer and their intensity is changed with different annealing condition. Its optical properties also have been investigated using fluorescence spectrometer. What’s more, its photoelectric parameters were studied by LED fast spectrometer. The constructed single crystal based white-light-emitting diode exhibits a high luminous efficiency of 140.89 lm/W, and a correlated color temperature of 4176 K as well as a color rendering index of 56.7, which reveal the prominent feasibility of the present single crystal material in white-light-emitting diode application.

  7. Radiation effects in corundum single crystals

    International Nuclear Information System (INIS)

    Gevorkyan, V.A.; Harutunyan, V.V.; Hakhverdyan, E.A.

    2005-01-01

    On the basis of new experimental results and analysis of publications it is shown that in the lattice of corundum crystals the high-energy particles create stable structural defects due to knocking out of atoms from normal sites of the anionic sublattice; this leads to the formation of F and F '+ centers as well as to other complex [Al i '+ F] type color centers. The essence of 'radiation memory' effect in corundum single crystals is that the high-energy particles irradiation, annealing at high temperatures and additional irradiation by X-rays result in the restoration of some spectral bands of the optical absorption in the range 200-650 nm

  8. Optical characterization of Pr3+-doped yttria-stabilized zirconia single crystals

    International Nuclear Information System (INIS)

    Savoini, B.; Munoz Santiuste, J.E.; Gonzalez, R.

    1997-01-01

    The optical absorption and fluorescence of Pr 3+ ions in yttria-stabilized zirconia single crystals are investigated. Fluorescence emissions from the 1 D 2 level are clearly dominant and low intensity emission lines from the 3 P 0 and 1 G 4 states are also observed. Analysis with the Judd-Ofelt theory of the absorption intensities has been made assuming that only ∼40% of the praseodymium ions contribute to the optical absorption bands. Quantum efficiency values of η( 3 P 0 )∼0.2 and η( 1 D 2 )∼ 1 are obtained at room temperature. 1 D 2 fluorescence quenching has been observed in heavily-doped samples due to cross relaxation processes among neighboring Pr 3+ ions. Analysis using the Inokuti-Hirayama model shows that electric dipole-dipole interactions are mainly responsible for the quenching effect. Pr 3+ ions are present in seven and sixfold configurations with a statistical distribution. The energy position of the 4f5d configuration is very different for each center. The fluorescence dynamics is explained by a mechanism involving thermally assisted population of the 3 P 1,2 + 1 I 6 upper levels and fast relaxation to the 1 D 2 level via states of the excited 4f5d configuration. copyright 1997 The American Physical Society

  9. Solvothermal syntheses, crystal structures, optical and thermal ...

    Indian Academy of Sciences (India)

    compounds 1–3 exhibit optical band gaps between 2.06 and 2.35 eV. Keywords. .... under a nitrogen stream of 100 mL min. −1 . 2.3 X-ray diffraction. Single-crystal ..... Liu G N, Guo G C, Wang M S, Cai L Z and Huang J S. 2010 Five dimeric ...

  10. Growth, structural, optical and surface analysis of piperazinium tartrate: A NLO single crystal

    Science.gov (United States)

    Gupta, Apurva; Raseel Rahman M., K.; Nair, Lekha

    2018-05-01

    Single crystal of piperazinium tartrate (PPZT) was grown by the slow evaporation solution growth technique at room temperature. Crystallinity of grown crystal was examined by powder X-ray diffraction. High transparency and wide band gap were observed in the UV-Visible spectroscopic studies. Intense and broad emissions were observed in the blue region, as that is indicated by photoluminescence spectroscopy. The quality of the grown PPZT single crystals were analyzed by the etching studies using the water as the etchant.

  11. Optical energy gaps and photoluminescence peaks of BaGa{sub 2}S{sub 4}:Er{sup 3+} and BaGa{sub 2}Se{sub 4}:Er{sup 3+} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Sung-Hyu [Chosun University, Kwangju (Korea, Republic of); Jin, Moon-Seog [Dongshin University, Naju (Korea, Republic of); Kim, Wha-Tek [Chonnam National University, Kwangju (Korea, Republic of)

    2005-12-15

    BaGa{sub 2}S{sub 4}:Er{sup 3+} and BaGa{sub 2}Se{sub 4}:Er{sup 3+} single crystals were grown by using the chemical transport reaction method. The optical energy gaps of the BaGa{sub 2}S{sub 4}:Er{sup 3+} and the BaGa{sub 2}Se{sub 4}:Er{sup 3+} single crystals were found to be 4.045 eV and 3.073 eV, respectively, at 11 K. The temperature dependence of the optical energy gap was well fitted by the Varshni equation. Sharp emission peaks were observed in the photoluminescence spectra of the single crystals and assigned to radiation recombination between split Stark levels of the Er{sup 3+} ion.

  12. Optical properties of the iron-based superconductor LiFeAs single crystal

    International Nuclear Information System (INIS)

    Min, Byeong Hun; Kwon, Yong Seung; Hong, Jong Beom; Yun, Jae Hyun; Bang, Yunkyu; Iizuka, Takuya; Kimura, Shin-ichi

    2013-01-01

    We have measured the reflectivity spectra of the LiFeAs (T c = 17.6 K) single crystal in the temperature range from 4 to 300 K. In the superconducting (SC) state (T c ), the clean opening of the optical absorption gap was observed below 25 cm −1 , indicating an isotropic full gap formation. In the normal state (T > T c ), the optical conductivity spectra display typical metallic behavior with the Drude-type spectra at low frequencies, but we found that the introduction of the two Drude components best fits the data, indicating the multiband nature of this compound. A theoretical analysis of the low-temperature data (T = 4 K c ) also suggests that two SC gaps best fit the data and their values were estimated as Δ 1 = 3.3 meV and Δ 2 = 1.59 meV, respectively. Using the Ferrell–Glover–Tinkham sum rule and dielectric function ϵ 1 (ω), the plasma frequency of the SC condensate (ω ps ) is consistently estimated to be 6665 cm −1 , implying that about 65% of the free carriers of the normal state condense into the SC condensate. To investigate the various interband transition processes (for ω > 200 cm −1 ), we have also performed the local-density approximation band calculation and calculated the optical spectra of the interband transitions. This theoretical result provided qualitative agreement with the experimental data below 4000 cm −1 . (paper)

  13. Growth, structural, optical, thermal and laser damage threshold studies of an organic single crystal: 1,3,5 – triphenylbenzene (TPB)

    International Nuclear Information System (INIS)

    Raja, R. Subramaniyan; Babu, G. Anandha; Ramasamy, P.

    2016-01-01

    Good quality single crystals of pure hydrocarbon 1,3,5-Triphenylbenzene (TPB) have been successfully grown using toluene as a solvent using controlled slow cooling solution growth technique. TPB crystallizes in orthorhombic structure with the space group Pna2 1 . The structural perfection of the grown crystal has been analysed by high resolution X-ray diffraction measurements. The range and percentage of the optical transmission are ascertained by recording the UV-vis spectrum. Thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study its thermal properties. Powder second harmonic generation studies were carried out to explore its NLO properties. Laser damage threshold value has been determined using Nd:YAG laser operating at 1064 nm.

  14. Properties of grazing-incidence pulsed Ti:sapphire laser oscillator

    International Nuclear Information System (INIS)

    Tamura, Koji

    2008-03-01

    A pulsed operation of a grazing-incidence double-grating Ti:sapphire laser oscillator that consists of a gain medium, back mirror, and a pair of gratings, was studied. A stable single-longitudinal-mode operation was achievable. From the calculation of the optical path trajectories, it can be explained by the increased beam walk-off from the gain medium by the introduction of the second grating compared with the conventional single-grating grazing-incidence cavity geometry. The improved spectral property was also explained by the calculations of increased dispersion. The results indicate that the oscillator configuration was useful for the applications which require stable mode operation and narrow linewidth such as the high resolution spectroscopy or the laser isotope separation. (author)

  15. A novel magneto-optical crystal Yb:TbVO4

    Science.gov (United States)

    Zhu, Xianchao; Tu, Heng; Hu, Zhanggui

    2018-04-01

    Highly transparent Yb:TbVO4 single crystal with dimensions of Ø27 × 41 mm3 alomost without scattering defects has been successfully grown by Czochralski technique. The spectra, thermal properties and laser-induced damage threshold were investigated in detailed. The Faraday rotation (FR) measurement was carried out by means of extinction method. The Verdet constant comes up to 80 rad m-1 T-1 at 1064 nm, significantly larger than TbVO4 (58 rad m-1 T-1) and TGG (40 rad m-1 T-1) reported. Meanwhile, the as-grown crystal presents lower absorption coefficient and higher magneto-optical figure of merit at measured wavelength in comparison with TGG. Moreover, the crystal exhibits a substantially improved extinction ratio (42 dB) in contrast with TbVO4 (29 dB), and exceeds the highest value of TGG (40 dB). These advantages make Yb:TbVO4 a highly promising magneto-optical material candidate for optical isolators in the visible-near infrared region.

  16. Sapphire implant based neuro-complex for deep-lying brain tumors phototheranostics

    Science.gov (United States)

    Sharova, A. S.; Maklygina, YU S.; Yusubalieva, G. M.; Shikunova, I. A.; Kurlov, V. N.; Loschenov, V. B.

    2018-01-01

    The neuro-complex as a combination of sapphire implant optical port and osteoplastic biomaterial "Collapan" as an Aluminum phthalocyanine nanoform photosensitizer (PS) depot was developed within the framework of this study. The main goals of such neuro-complex are to provide direct access of laser radiation to the brain tissue depth and to transfer PS directly to the pathological tissue location that will allow multiple optical phototheranostics of the deep-lying tumor region without repeated surgical intervention. The developed complex spectral-optical properties research was carried out by photodiagnostics method using the model sample: a brain tissue phantom. The optical transparency of sapphire implant allows obtaining a fluorescent signal with high accuracy, comparable to direct measurement "in contact" with the tissue.

  17. Fabrication of high-quality single-crystal Cu thin films using radio-frequency sputtering.

    Science.gov (United States)

    Lee, Seunghun; Kim, Ji Young; Lee, Tae-Woo; Kim, Won-Kyung; Kim, Bum-Su; Park, Ji Hun; Bae, Jong-Seong; Cho, Yong Chan; Kim, Jungdae; Oh, Min-Wook; Hwang, Cheol Seong; Jeong, Se-Young

    2014-08-29

    Copper (Cu) thin films have been widely used as electrodes and interconnection wires in integrated electronic circuits, and more recently as substrates for the synthesis of graphene. However, the ultra-high vacuum processes required for high-quality Cu film fabrication, such as molecular beam epitaxy (MBE), restricts mass production with low cost. In this work, we demonstrated high-quality Cu thin films using a single-crystal Cu target and radio-frequency (RF) sputtering technique; the resulting film quality was comparable to that produced using MBE, even under unfavorable conditions for pure Cu film growth. The Cu thin film was epitaxially grown on an Al2O3 (sapphire) (0001) substrate, and had high crystalline orientation along the (111) direction. Despite the 10(-3) Pa vacuum conditions, the resulting thin film was oxygen free due to the high chemical stability of the sputtered specimen from a single-crystal target; moreover, the deposited film had >5× higher adhesion force than that produced using a polycrystalline target. This fabrication method enabled Cu films to be obtained using a simple, manufacturing-friendly process on a large-area substrate, making our findings relevant for industrial applications.

  18. Transmission Electron Microscopy (TEM) Sample Preparation of Si(1-x)Gex in c-Plane Sapphire Substrate

    Science.gov (United States)

    Kim, Hyun Jung; Choi, Sang H.; Bae, Hyung-Bin; Lee, Tae Woo

    2012-01-01

    The National Aeronautics and Space Administration-invented X-ray diffraction (XRD) methods, including the total defect density measurement method and the spatial wafer mapping method, have confirmed super hetero epitaxy growth for rhombohedral single crystalline silicon germanium (Si1-xGex) on a c-plane sapphire substrate. However, the XRD method cannot observe the surface morphology or roughness because of the method s limited resolution. Therefore the authors used transmission electron microscopy (TEM) with samples prepared in two ways, the focused ion beam (FIB) method and the tripod method to study the structure between Si1-xGex and sapphire substrate and Si1?xGex itself. The sample preparation for TEM should be as fast as possible so that the sample should contain few or no artifacts induced by the preparation. The standard sample preparation method of mechanical polishing often requires a relatively long ion milling time (several hours), which increases the probability of inducing defects into the sample. The TEM sampling of the Si1-xGex on sapphire is also difficult because of the sapphire s high hardness and mechanical instability. The FIB method and the tripod method eliminate both problems when performing a cross-section TEM sampling of Si1-xGex on c-plane sapphire, which shows the surface morphology, the interface between film and substrate, and the crystal structure of the film. This paper explains the FIB sampling method and the tripod sampling method, and why sampling Si1-xGex, on a sapphire substrate with TEM, is necessary.

  19. Scaling submillimeter single-cycle transients toward megavolts per centimeter field strength via optical rectification in the organic crystal OH1.

    Science.gov (United States)

    Ruchert, Clemens; Vicario, Carlo; Hauri, Christoph P

    2012-03-01

    We present the generation of high-power single-cycle terahertz (THz) pulses in the organic salt crystal 2-[3-(4-hydroxystyryl)-5.5-dimethylcyclohex-2-enylidene]malononitrile or OH1. Broadband THz radiation with a central frequency of 1.5 THz (λ(c)=200 μm) and high electric field strength of 440 kV/cm is produced by optical rectification driven by the signal of a powerful femtosecond optical parametric amplifier. A 1.5% pump to THz energy conversion efficiency is reported, and pulse energy stability better than 1% RMS is achieved. An approach toward the realization of higher field strength is discussed. © 2012 Optical Society of America

  20. Low-Threshold Lasing from 2D Homologous Organic-Inorganic Hybrid Ruddlesden-Popper Perovskite Single Crystals.

    Science.gov (United States)

    Raghavan, Chinnambedu Murugesan; Chen, Tzu-Pei; Li, Shao-Sian; Chen, Wei-Liang; Lo, Chao-Yuan; Liao, Yu-Ming; Haider, Golam; Lin, Cheng-Chieh; Chen, Chia-Chun; Sankar, Raman; Chang, Yu-Ming; Chou, Fang-Cheng; Chen, Chun-Wei

    2018-05-09

    Organic-inorganic hybrid two-dimensional (2D) perovskites have recently attracted great attention in optical and optoelectronic applications due to their inherent natural quantum-well structure. We report the growth of high-quality millimeter-sized single crystals belonging to homologous two-dimensional (2D) hybrid organic-inorganic Ruddelsden-Popper perovskites (RPPs) of (BA) 2 (MA) n-1 Pb n I 3 n+1 ( n = 1, 2, and 3) by a slow evaporation at a constant-temperature (SECT) solution-growth strategy. The as-grown 2D hybrid perovskite single crystals exhibit excellent crystallinity, phase purity, and spectral uniformity. Low-threshold lasing behaviors with different emission wavelengths at room temperature have been observed from the homologous 2D hybrid RPP single crystals. Our result demonstrates that solution-growth homologous organic-inorganic hybrid 2D perovskite single crystals open up a new window as a promising candidate for optical gain media.

  1. Study on high gain broadband optical parametric chirped pulse amplification

    International Nuclear Information System (INIS)

    Zhang, S.K.; Fujita, M.; Yamanaka, C.; Yoshida, H.; Kodama, R.; Fujita, H.; Nakatsuka, M.; Izawa, Y.

    2000-01-01

    Optical parametric chirped pulse amplification has apparent advantages over the current schemes for high energy ultrashort pulse amplification. High gain in a single pass amplification, small B-integral, low heat deposition, high contrast ratio and, especially the extremely broad gain bandwidth with large-size crystals available bring people new hope for over multi-PW level at which the existing Nd:glass systems suffered difficulties. In this paper we present simulation and experimental studies for a high gain optical parametric chirped pulse amplification system which may be used as a preamplifier to replace the current complicated regenerative system or multi-pass Ti:sapphire amplifiers. Investigations on the amplification bandwidth and gain with BBO are performed. Analysis and discussions are also given. (author)

  2. Neutron reflectivity study of substrate surface chemistry effects on supported phospholipid bilayer formation on (1120) sapphire.

    Energy Technology Data Exchange (ETDEWEB)

    Oleson, Timothy A. [University of Wisconsin, Madison; Sahai, Nita [University of Akron; Wesolowski, David J [ORNL; Dura, Joseph A [ORNL; Majkrzak, Charles F [ORNL; Giuffre, Anthony J. [University of Wisconsin, Madison

    2012-01-01

    Oxide-supported phospholipid bilayers (SPBs) used as biomimetric membranes are significant for a broad range of applications including improvement of biomedical devices and biosensors, and in understanding biomineralization processes and the possible role of mineral surfaces in the evolution of pre-biotic membranes. Continuous-coverage and/or stacjed SPBs retain properties (e.,g. fluidity) more similar to native biological membranes, which is desirable for most applications. Using neutron reflectivity, we examined face coverage and potential stacking of dipalmitoylphosphatidylcholine (DPPC) bilayers on the (1120) face of sapphire (a-Al2O3). Nearly full bilayers were formed at low to neutral pH, when the sapphire surface is positively charged, and at low ionic strength (l=15 mM NaCl). Coverage decreased at higher pH, close to the isoelectric point of sapphire, and also at high I>210mM, or with addition of 2mM Ca2+. The latter two effects are additive, suggesting that Ca2+ mitigates the effect of higher I. These trends agree with previous results for phospholipid adsorption on a-Al2O3 particles determined by adsorption isotherms and on single-crystal (1010) sapphire by atomic force microscopy, suggesting consistency of oxide surface chemistry-dependent effects across experimental techniques.

  3. Optical Trapping of Ion Coulomb Crystals

    Directory of Open Access Journals (Sweden)

    Julian Schmidt

    2018-05-01

    Full Text Available The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

  4. The use of single-crystal iron frames in transient field measurements

    International Nuclear Information System (INIS)

    Zalm, P.C.; Laan, J. van der; Middelkoop, G. van

    1979-01-01

    Single-crystal Fe frames have been investigated for use as a ferromagnetic backing in transient magnetic field experiments. For this purpose the surface magnetization as a function of applied magnetic field has been determined with the magneto-optical Kerr effect. The frames, which have two sides parallel to the crystal axis, can be fully magnetized at low external fields such that fringing fields are negligibly small. These single-crystal Fe backings have been used in several transient magnetic field experiments. Comparison of the measured precession angles with previous results, obtained in polycrystalline Fe foils at high external magnetic fields, shows that the single-crystal backings are satisfactory. After extended periods of heavy-ion bombardment the crystals exhibited no radiation damage effects. The absence of fringing fields leads to a reduction of a factor of four in the measuring time for transient field experiments. (Auth.)

  5. Using a novel spectroscopic reflectometer to optimize a radiation-hardened submicron silicon-on-sapphire CMOS process; Utilisation d'une nouvelle reflectometrie spectroscopique pour optimiser un procede de fabrication CMOS/SOS durci aux radiations

    Energy Technology Data Exchange (ETDEWEB)

    Do, N.T.; Zawaideh, E.; Vu, T.Q.; Warren, G.; Mead, D. [Raytheon Systems company, Microelectronics Div., Newport Beach, California (United States); Li, G.P.; Tsai, C.S. [California Univ., School of Engineering, Newport Beach, CA (United States)

    1999-07-01

    A radiation-hardened sub-micron silicon-on-sapphire CMOS process is monitored and optimized using a novel optical technique based on spectroscopic reflectometry. Quantitative measurements of the crystal quality, surface roughness, and device radiation hardness show excellent correlation between this technique and the Atomic Force Microscopy. (authors)

  6. Nonlinear optical crystals a complete survey

    CERN Document Server

    Nikogosyan, David N

    2005-01-01

    Nonlinear optical crystals are widely used in modern optical science and technology for frequency conversion of laser light, i.e. to generate laser radiation at any specific wavelength in visible, UV or IR spectral regions. This unrivalled reference book contains the most complete and up-to-date information on properties of nonlinear optical crystals. It includes: * Database of 63 common and novel nonlinear optical crystals * Periodically-poled and self-frequency-doubling materials * Full description of linear and nonlinear optical properties * Significant amount of crystallophysical, thermophysical, spectroscopic, electro-optic and magneto-optic information * 7 mini-reviews on novel applications, such as deep-UV light generation, terahertz-wave generation, ultrashort laser pulse compression, photonic band-gap crystals, x3 nonlinearity, etc. * More than 1500 different references with full titles It is a vital source of information for scientists and engineers dealing with modern applications of nonlinear opti...

  7. Growth of single-crystal YAG fiber optics.

    Science.gov (United States)

    Nie, Craig D; Bera, Subhabrata; Harrington, James A

    2016-07-11

    Single-crystal YAG (Y3Al5O12) fibers have been grown by the laser heated pedestal growth technique with losses as low as 0.3 dB/m at 1.06 μm. These YAG fibers are as long as about 60 cm with diameters around 330 μm. The early fibers were grown from unoriented YAG seed fibers and these fibers exhibited facet steps or ridges on the surface of the fiber. However, recently we have grown fibers using an oriented seed to grow step-free fibers. Scattering losses made on the fibers indicate that the scattering losses are equal to about 30% of the total loss.

  8. Photoinduced Optical Spectroscopy of La2CuO4+x Single Crystals and C60 Thin Films

    International Nuclear Information System (INIS)

    Bazhenov, A.V.; Gorbunov, A.V.; Timofeev, V.B.

    1995-01-01

    The evolution of both vibration and electronic spectra of insulating La 2 CuO 4+x single crystals upon charge-transfer gap photoexcitation has been studied by means of photoinduced reflection spectroscopy. Interaction of self-localized hole with some of the A g , B 2g (B 3g ), B 3u optical phonons has been observed. Formation of self-localized hole state and its multiparticle complexes is supposed. Photoinduced absorption in C 60 thin films has been found to differ essentially from that in cuprates

  9. Growth and characterization of unidirectional benzil single crystal for photonic applications

    Science.gov (United States)

    Saranraj, A.; Thirupathy, J.; Dhas, S. Sahaya Jude; Jose, M.; Vinitha, G.; Dhas, S. A. Martin Britto

    2018-06-01

    Organic nonlinear optical benzil single crystal of fine quality with the dimensions of 168 × 14 mm2 was successfully grown in (100) plane from saturated solution by unidirectional SR method. The structural identity of the grown crystal was confirmed by powder XRD. High-resolution X-ray diffraction analysis indicates the crystalline perfection of the grown benzil crystal. The optical analysis was carried out by UV-visible spectroscopy which shows that the benzil crystal's cut off wavelength is 437 nm. The dielectric constant and dielectric loss of benzil crystal are found to be very much depending upon temperature and frequency. Ferroelectric nature of grown crystal was identified by P- E hysteresis analysis and to find the values of spontaneous polarization and coercive field. The laser damage threshold energy was studied with the help of Nd:YAG laser. The presence of third harmonic generation was identified by z-scan techniques.

  10. Optics of globular photonic crystals

    International Nuclear Information System (INIS)

    Gorelik, V S

    2007-01-01

    The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ∼200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported. (review)

  11. Single-transverse-mode Ti:sapphire rib waveguide laser

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, Markus

    2005-01-01

    Laser operation of Ti:sapphire rib waveguides fabricated using photolithography and ion beam etching in pulsed laser deposited layers is reported. Polarized laser emission was observed at 792.5 nm with an absorbed pump power threshold of 265 mW, which is more than a factor of 2 lower in comparison

  12. Growth and characterization of 2-Methylimidazolium D-tartrate single crystal

    Science.gov (United States)

    Srinivasan, T. P.; Anandhi, S.; Gopalakrishnan, R.

    2011-03-01

    Single crystal of 2-Methylimidazolium D-tartrate (2MImdT; C8N2O6H12) has been grown by slow evaporation solution growth technique at room temperature using mixed solvents of ethanol and deionized water. Single crystal X-ray diffraction study confirms that 2-Methylimidazolium D-tartrate belongs to monoclinic crystal system with non-centrosymmetric space group P21. The Fourier transform infrared spectrum of 2-Methylimidazolium D-tartrate reveals the presence of methyl and carboxyl functional groups in the compound. The mechanical properties of 2MImdT crystal were studied. The theoretical factor group analysis predicts 168 optical modes in the title compound. The dielectric behavior of 2MImdT crystals was studied at different frequencies and temperatures. Decomposition and melting point of 2MImdT were found using thermal measurements. SHG behavior of the title compound was demonstrated using Q-switched Nd:YAG laser.

  13. Mechanism of linear and nonlinear optical properties of bis-thiourea cadmium chloride single crystal

    International Nuclear Information System (INIS)

    Yang, J.T.; Luo, S.J.; Yi, L.; Laref, A.

    2013-01-01

    Within the generalized gradient approximation (GGA), a calculation of the electronic structure of a semiorganic crystal named bis-thiourea cadmium chloride (BTCC) was performed, then the linear and nonlinear optical responses were obtained over a wide energy range, using a scissor energy of 1.30 eV, and our results are in good agreement with the experiments. The accurate full-potential projected augmented wave (FP-PAW) method was used. The prominent spectrum of the second harmonic generation (SHG) was successfully correlated with the dielectric function in terms of single- and double-photon resonances. Both the virtual electron (VE) and virtual hole (VH) processes make contributions to the SHG of BTCC crystal, and the VH process is enhanced by the Cd-centered tetrahedron. The SHG effect of the semiorganic material is attributed to the charge transfer (CT). The CT model for the semiorganic crystal is named as “M-Π O ⋯X”. “M” is a metal atom providing electrons, “Π O ” is a π-conjugated covalent of an organic molecule, and “X” is a high electronegativity atom. The CT across the BTCC molecule is along a π-electron conjugation covalence bond, and the delocalized electrons of sulfur provide an excellent bridge. The strong “pull” effect for the CT is due to the intramolecular hydrogen bonds provided by the chlorine with the high electron affinity.

  14. Laser-induced optical effects in triglycine-zinc chloride single crystals

    International Nuclear Information System (INIS)

    Wojciechowski, A.; Kityk, I.V.; Lakshminarayana, G.; Fuks-Janczarek, I.; Berdowski, J.; Berdowska, E.; Tylczynski, Z.

    2010-01-01

    The influence of irradiation by a cw 532 nm laser on the behavior of the absorption and optical second harmonic generation of triglicyne-zinc chloride crystal has been studied. Additional absorption bands correlate well with the time of the cw laser exposure. These lines occur at 260 nm, 305 nm, and, with small intensity, at 355 nm. The remaining part of the spectra shows substantially less changes. According to the performed quantum chemical simulations, one may expect that the observed dependences and the stability of the observed photoinduced changes are caused by formation of polarized electron-phonon states and the principal role should belong here to the electron-phonon anharmonicities, which cause the effects described by the non-polar third rank polar tensor like optical second harmonic generation. The increasing optical SHG signal shows a clear correlation with the behavior of the green laser-532 nm. It is important principal that for the blue laser-405 nm, the SHG effect is substantially less. This may reflect that the additional absorption maxima may be responsible for the non-linear optical effects. The effect demonstrates a slow time decay.

  15. Optical cleaning of lithium niobate crystals

    International Nuclear Information System (INIS)

    Koesters, Michael

    2010-01-01

    An all-optical method for the removal of photoexcitable electrons from photorefractive centers to get rid of optical damage in lithium niobate crystals is presented, the so-called ''optical cleaning''. The method combines the photovoltaic drift of electrons with ionic charge compensation at sufficiently high temperatures of about 180 C. Optimum choice of the light pattern plus heat dramatically decreases the concentration of photoexcitable electrons in the exposed region leading to a suppression of optical damage. Experiments with slightly iron-doped lithium niobate crystals have shown an increase of the threshold for optical damage of more than 1000 compared to those of untreated crystals. (orig.)

  16. Optical cleaning of lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Koesters, Michael

    2010-01-15

    An all-optical method for the removal of photoexcitable electrons from photorefractive centers to get rid of optical damage in lithium niobate crystals is presented, the so-called ''optical cleaning''. The method combines the photovoltaic drift of electrons with ionic charge compensation at sufficiently high temperatures of about 180 C. Optimum choice of the light pattern plus heat dramatically decreases the concentration of photoexcitable electrons in the exposed region leading to a suppression of optical damage. Experiments with slightly iron-doped lithium niobate crystals have shown an increase of the threshold for optical damage of more than 1000 compared to those of untreated crystals. (orig.)

  17. Synthesis of formamidinium lead iodide perovskite bulk single crystal and its optical properties

    Science.gov (United States)

    Zheng, Hongge; Duan, Junjie; Dai, Jun

    2017-07-01

    Formamidinium lead iodide (FAPbI3) is a promising hybrid perovskite material for optoelectronic devices. We synthesized bulk single crystal FAPbI3 by a rapid solution crystallization method. X-ray diffraction (XRD) was performed to characterize the crystal structure. Temperature-dependent photoluminescence (PL) spectra of the bulk single crystal FAPbI3 were measured from 10 to 300 K to explain PL recombination mechanism. It shows that near band edge emission blueshifts with the temperature increasing from 10 to 120 K and from 140 K to room temperature, a sudden emission band redshift demonstrates near 140 K because of the phase transition from orthorhombic phase to cubic phase. From the temperature-dependent PL spectra, the temperature coefficients of the bandgap and thermal activation energies of FAPbI3 perovskite are fitted.

  18. Optical properties of CsI single crystals irradiated with neutrons at low temperature

    International Nuclear Information System (INIS)

    Okada, M.; Atobe, K.; Itatani, N.; Ozawa, K.

    1998-01-01

    Optical properties of the irradiation-induced-defects in neutron-irradiated CsI single crystals have been investigated. The nominally pure CsI crystals are irradiated by reactor fast neutrons (E>0.1 MeV) with a fluence of 1.4 x 10 15 n/cm 2 at 20 K and by γ-rays from 60 Co source to a dose of 1.5 x 10 4 Gy at liquid nitrogen temperature (LNT). After the irradiations, isochronal annealings are performed to investigate the thermal behavior of the defects. The glow peaks of the thermoluminescence (TL) in each sample irradiated with neutrons at 20 K and with γ-rays at LNT are observed at about 100, 160 and 220 K. In the neutron-irradiated samples at 20 K, the emission band at 338 nm is observed at LNT. It is supposed that this emission band occurs by an excitation of γ-rays from 134 Cs, which is radioactivated by thermal neutrons among the reactor radiations. It is confirmed that the temperature dependence of the 338 nm band is similar with that of the emission band due to the self-trapped exciton which is introduced into the non-irradiated samples illuminated by higher energy photons. (orig.)

  19. Optical properties of CsI single crystals irradiated with neutrons at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Okada, M. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Nakagawa, M. [Faculty of Education, Kagawa Univ., Takamatsu, Kagawa (Japan); Atobe, K. [Faculty of Science, Naruto Univ. of Education, Naruto, Tokushima (Japan); Itatani, N.; Ozawa, K. [Horiba Ltd., Minamiku, Kyoto (Japan)

    1998-05-01

    Optical properties of the irradiation-induced-defects in neutron-irradiated CsI single crystals have been investigated. The nominally pure CsI crystals are irradiated by reactor fast neutrons (E>0.1 MeV) with a fluence of 1.4 x 10{sup 15} n/cm{sup 2} at 20 K and by {gamma}-rays from {sup 60}Co source to a dose of 1.5 x 10{sup 4} Gy at liquid nitrogen temperature (LNT). After the irradiations, isochronal annealings are performed to investigate the thermal behavior of the defects. The glow peaks of the thermoluminescence (TL) in each sample irradiated with neutrons at 20 K and with {gamma}-rays at LNT are observed at about 100, 160 and 220 K. In the neutron-irradiated samples at 20 K, the emission band at 338 nm is observed at LNT. It is supposed that this emission band occurs by an excitation of {gamma}-rays from {sup 134}Cs, which is radioactivated by thermal neutrons among the reactor radiations. It is confirmed that the temperature dependence of the 338 nm band is similar with that of the emission band due to the self-trapped exciton which is introduced into the non-irradiated samples illuminated by higher energy photons. (orig.) 13 refs.

  20. Orientation dependence of the thermal fatigue of nickel alloy single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Dul' nev, R A; Svetlov, I L; Bychkov, N G; Rybina, T V; Sukhanov, N N

    1988-11-01

    The orientation dependence of the thermal stability and the thermal fatigue fracture characteristics of single crystals of MAR-M200 nickel alloy are investigated experimentally using X-ray diffraction analysis and optical and scanning electron microscopy. It is found that specimens with the 111-line orientation have the highest thermal stability and fatigue strength. Under similar test conditions, the thermal fatigue life of single crystals is shown to be a factor of 1.5-2 higher than that of the directionally solidified and equiaxed alloys. 6 references.

  1. Temperature-modulated annealing of c-plane sapphire for long-range-ordered atomic steps

    International Nuclear Information System (INIS)

    Yatsui, Takashi; Kuribara, Kazunori; Sekitani, Tsuyoshi; Someya, Takao; Yoshimoto, Mamoru

    2016-01-01

    High-quality single-crystalline sapphire is used to prepare various semiconductors because of its thermal stability. Here, we applied the tempering technique, which is well known in the production of chocolate, to prepare a sapphire substrate. Surprisingly, we successfully realised millimetre-range ordering of the atomic step of the sapphire substrate. We also obtained a sapphire atomic step with nanometre-scale uniformity in the terrace width and atomic-step height. Such sapphire substrates will find applications in the preparation of various semiconductors and devices. (paper)

  2. Synthesis, growth, structural, optical and thermal properties of a new organic salt crystal: 3-nitroanilinium trichloroacetate

    Science.gov (United States)

    Selvakumar, E.; Chandramohan, A.; Anandha Babu, G.; Ramasamy, P.

    2014-09-01

    A new organic non-linear optical salt 3-nitroanilinium trichloroacetate has been synthesized and single crystals grown by slow solvent evaporation solution growth technique at room temperature using methanol as the solvent. The 1H and 13C Nuclear magnetic resonance spectra were recorded to establish the molecular structure of the title salt. The crystal structure of the title crystal has been determined by single crystal X-ray diffraction analysis and it belongs to monoclinic crystal system with non-centrosymmetric space group P21. Fourier transform infrared spectral study has been carried out to confirm the presence of various functional groups. The optical transmittance spectrum was recorded in the range 200-2500 nm, to find the optical transmittance window and lower cut off wavelength. The thermo gravimetric and differential thermal analyses were carried out to establish the thermal stability of the title crystal. The second harmonic generation in the title crystal was confirmed by the modified Kurtz-Perry powder test employing the Nd: YAG laser as the source for infrared radiation.

  3. Optical transmission of nematic liquid crystal 5CB doped by single-walled and multi-walled carbon nanotubes.

    Science.gov (United States)

    Lisetski, L N; Fedoryako, A P; Samoilov, A N; Minenko, S S; Soskin, M S; Lebovka, N I

    2014-08-01

    Comparative studies of optical transmission of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), dispersed in nematic liquid crystal matrix 5CB, were carried out. The data evidence violations of Beer-Lambert-Bouguer (BLB) law both in cell thickness and concentration dependencies. The most striking is the fact that optical transmission dependencies for SWCNTs and MWCNTs were quite different in the nematic phase, but they were practically indistinguishable in the isotropic phase. Monte Carlo simulations of the impact of aggregation on direct transmission and violation of BLB law were also done. The results were discussed accounting for the tortuous shape of CNTs, their physical properties and aggregation, as well as strong impact of perturbations of the nematic 5CB structure inside coils and in the vicinity of CNT aggregates.

  4. Synthesis, growth, physicochemical properties and DFT calculations of 2-naphthol substituted Mannich base 1-(morpholino(phenyl) methyl) naphthalen-2-ol: A non linear optical single crystal

    Science.gov (United States)

    Dennis Raj, A.; Jeeva, M.; Shankar, M.; Venkatesa Prabhu, G.; Vimalan, M.; Vetha Potheher, I.

    2017-11-01

    2-Naphthol substituted Mannich base 1-morpholino(phenyl)methyl)naphthalen-2-ol (MPMN), a potential NLO active organic single crystal was developed using acetonitrile as a solvent by slow evaporation method. The experimental and theoretical analysis made towards the exploitation in the field of electro-optic and NLO applications. The cubic structure with non-centrosymmetric space group Cc was confirmed and cell dimensions of the grown crystal were obtained from single crystal X-ray diffraction (XRD) study. The formation of the Csbnd Nsbnd C vibrational band at 1115 cm-1 in Fourier Transform Infra-Red (FTIR) analysis confirms the formation of MPMN compound. The placement of protons and carbons of MPMN were identified from Nuclear Magnetic Resonance Spectroscopy (NMR) analysis. The wide optical absorption window and the lower cutoff wavelength of MPMN show the suitability of the material for the various laser related applications. The presence of dislocations and growth pattern of crystal were analyzed using chemical etching technique. The Second Harmonic Generation (SHG) of MPMN was found to be 1.57 times greater than the standard KDP crystal. The laser damage threshold was measured by using Nd: YAG laser beam passed through the sample and it was found to be 1.006 GW/cm2. The electronic structure of the molecular system and the optical properties were also studied from quantum chemical calculations using Density Functional Theory (DFT) and reported for the first time.

  5. Scintillation and optical properties of Ce{sup 3+}-doped CaGdAl{sub 3}O{sub 7} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Masaki, E-mail: masaki.mori.mz4@ms.naist.jp [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma-shi, Nara 630-0192 (Japan); Nakauchi, Daisuke; Okada, Go [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma-shi, Nara 630-0192 (Japan); Fujimoto, Yutaka [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579 (Japan); Kawaguchi, Noriaki [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma-shi, Nara 630-0192 (Japan); Koshimizu, Masanori [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579 (Japan); Yanagida, Takayuki [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma-shi, Nara 630-0192 (Japan)

    2017-06-15

    The single crystals of 0, 0.6, 1, 1.6 and 2 mol% Ce doped CaGdAl{sub 3}O{sub 7} (Ce:CGAM) were grown by the Floating Zone method, and investigated on photoluminescence (PL) and scintillation properties. In the PL spectra, a broad emission appeared over 380–500 nm under 280 and 360 nm excitations with the quantum yield of 33.8–38.8%. Under a vacuum ultraviolet excitation (90 nm) using a synchrotron source, non-doped CGAM single crystal showed broad emissions over 250–650 nm. The PL decay time profiles followed a monotonic exponential decay with a decay time constant of around 33 ns. The scintillation spectra were similar to those of PL. All of the samples exhibited a clear photoabsorption peak and Compton edge in the pulse height spectra measured under {sup 137}Cs γ-ray irradiation, and the absolute scintillation light yield (LY) was highest for the 2% Ce-doped sample with the value of 3300±300 ph/MeV. The scintillation decay profiles were approximated by a third order exponential decay function, and the extracted decay time of Ce{sup 3+} emission component was around 36–44 ns. Among all the samples, 2%Ce:CGAM single crystal sample showed the best afterglow level as a scintillator under X-ray irradiation. - Highlights: •Ce{sup 3+}-doped CaGdAl{sub 3}O{sub 7} single crystals were synthesized by the FZ method. •Optical and scintillation properties of Ce{sup 3+}-doped CaGdAl{sub 3}O{sub 7} were investigated. •Photoabsorption peak in a pulse height spectrum was clearly observed under γ-rays.

  6. Effect of power history on the shape and the thermal stress of a large sapphire crystal during the Kyropoulos process

    Science.gov (United States)

    Nguyen, Tran Phu; Chuang, Hsiao-Tsun; Chen, Jyh-Chen; Hu, Chieh

    2018-02-01

    In this study, the effect of the power history on the shape of a sapphire crystal and the thermal stress during the Kyropoulos process are numerically investigated. The simulation results show that the thermal stress is strongly dependent on the power history. The thermal stress distributions in the crystal for all growth stages produced with different power histories are also studied. The results show that high von Mises stress regions are found close to the seed of the crystal, the highly curved crystal surface and the crystal-melt interface. The maximum thermal stress, which occurs at the crystal-melt interface, increases significantly in value as the crystal expands at the crown. After this, there is reduction in the maximum thermal stress as the crystal lengthens. There is a remarkable enhancement in the maximum von Mises stress when the crystal-melt interface is close to the bottom of the crucible. There are two obvious peaks in the maximum Von Mises stress, at the end of the crown stage and in the final stage, when cracking defects can form. To alleviate this problem, different power histories are considered in order to optimize the process to produce the lowest thermal stress in the crystal. The optimal power history is found to produce a significant reduction in the thermal stress in the crown stage.

  7. Effects of Manganese (Ii Sulphate on Structural, Spectral, Optical, Thermal and Mechanical Properties of L-Alanine Sodium Sulphate Single Crystals

    Directory of Open Access Journals (Sweden)

    F. Praveena

    2017-04-01

    Full Text Available New Non-linear Optical materials have been attracting in the research world for their potential applications in emerging opto-electronic technology. The dipolar nature of amino acid leads to peculiar physical and chemical properties, thus making a good candidate for NLO applications. Single crystals of manganese(II sulphate doped L-Alanine sodium sulphate(LASS has been synthesized by slow evaporation technique. Structural property of the grown crystals are characterized by X-ray powder diffraction,FT-IR spectral analysis conforms all the functional groups. Thermogravity (TG and differential themogravimetric (DTA analysis have been performed to study the thermal stability of the crystals. The second harmonic generation efficiency was measured by Kurtz-Perry powder technique. The transmission and absorption of electromagnetic radiation is analysed through UV-VIS spectrum. Microhardness was measured at different applied load to understand the mechanical stability of the crystal.

  8. Theoretical study of Cherenkov radiation emission in anisotropic uniaxial crystals

    Energy Technology Data Exchange (ETDEWEB)

    Delbart, A; Derre, J

    1996-04-01

    A theoretical review of the Cherenkov radiation emission in uniaxial crystals is presented. The formalism of C. Muzicar in terms of energetic properties of the emitted waves are corrected. This formalism is used to simulate the Cherenkov radiation emission in a strongly birefringent sodium nitrate crystal (NaNO{sub 3}) and to investigate the consequences of the slight anisotropy of sapphire (Al{sub 2}O{sub 3}) on the design of the Optical Trigger. (author). 12 refs. Submitted to Physical Review, D (US).

  9. Sources of optical distortion in rapidly grown crystals of KH2PO4

    International Nuclear Information System (INIS)

    De Yoreo, J.J.; Zaitseva, N.P.; Woods, B.W.; Land, T.A.; Rek, Z.U.

    1995-01-01

    We report results of x-ray topographic and optical measurements on KH 2 PO 4 crystals grown at rates of 5 to 30mm/day. We show that optical distortion in these crystals is caused primarily by 3 sources: dislocations, differences in composition between adjacent growth sectors of the crystal, and differences in composition between adjacent sectors of vicinal growth hillocks within a single growth sector of the crystal. We find that the compositional heterogeneities cause spatial variations in the refractive index and induced distortion of the transmitted wave front while large groups of dislocations are responsible for strain induced birefringence which leads to beam depolarization

  10. EPR and optical investigation of Mn2+ doped L-histidine-4-nitrophenolate 4-nitrophenol single crystal

    Science.gov (United States)

    Prabakaran, R.; Subramanian, P.

    2018-04-01

    Single crystals of L-histidine-4-nitrophenolate 4-nitrophenol[LHFNP] complex doped with Mn2+ were grown by the slow evaporation method at room temperature. The EPR spectrum reveals the entry of one Mn2+ ion in the lattice. The angular variation plot was drawn between the angles and the magnetic field position. The spin Hamiltonian parameters were obtained by EPR-NMR program. The D and E values show the rhombic field around the ion and is an interstitial one. The g value obtained here suggests that the Mn2+ ion experiences a strong field and there is a transfer of electron from the metal ion to the ligand atom. The optical absorption study shows various bands and are assigned to the transition from the ground state 6A1g(S). The Racah and crystal field parameters have also been evaluated and fitted to the experimental values. The Racah parameter shows the covalent bonding between the metal ion to the ligand.

  11. Scintillation characteristics of LiB3O5 and β-BaB2O4 single crystals

    International Nuclear Information System (INIS)

    Nazarenko, B.P.; Pedash, V.Yu.; Shekhovtsov, A.N.; Tarasov, V.A.; Zelenskaya, O.V.

    2006-01-01

    LiB 3 O 5 and β-BaB 2 O 4 single crystals have been grown by the top seeded solution growth technique. The optical characteristics and scintillation parameters of the grown single crystals have been tested and discussed

  12. Large-surface-area diamond (111) crystal plates for applications in high-heat-load wavefront-preserving X-ray crystal optics.

    Science.gov (United States)

    Stoupin, Stanislav; Antipov, Sergey; Butler, James E; Kolyadin, Alexander V; Katrusha, Andrey

    2016-09-01

    Fabrication and results of high-resolution X-ray topography characterization of diamond single-crystal plates with large surface area (10 mm × 10 mm) and (111) crystal surface orientation for applications in high-heat-load X-ray crystal optics are reported. The plates were fabricated by laser-cutting of the (111) facets of diamond crystals grown using high-pressure high-temperature methods. The intrinsic crystal quality of a selected 3 mm × 7 mm crystal region of one of the studied samples was found to be suitable for applications in wavefront-preserving high-heat-load crystal optics. Wavefront characterization was performed using sequential X-ray diffraction topography in the pseudo plane wave configuration and data analysis using rocking-curve topography. The variations of the rocking-curve width and peak position measured with a spatial resolution of 13 µm × 13 µm over the selected region were found to be less than 1 µrad.

  13. EPR and optical absorption study of Cu{sup 2+} doped lithium sulphate monohydrate (LSMH) single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sheela, K. Juliet; Subramanian, P., E-mail: psubramaniangri@gmail.com [Department of Physics, Gandhigram Rural Institute-Deemed University, Gandhigram, Dindigul-624302, Tamilnadu (India); Krishnan, S. Radha; Shanmugam, V. M. [CSIR-Central Electrochemical Research Institute, Karaikudi-63006, Tamilnadu (India)

    2016-05-23

    EPR study of Cu{sup 2+} doped NLO active Lithium Sulphate monohydrate (Li{sub 2}SO{sub 4.}H{sub 2}O) single crystals were grown successfully by slow evaporation method at room temperature. The principal values of g and A tensors indicate existence of orthorhombic symmetry around the Cu{sup 2+} ion. From the direction cosines of g and A tensors, the locations of Cu{sup 2+} in the lattice have been identified as interstitial site. Optical absorption confirms the rhombic symmetry and ground state wave function of the Cu{sup 2+} ion in a lattice as d{sub x2-y2}.

  14. Blue luminescence in Tm3+-doped KGd(WO4)2 single crystals

    International Nuclear Information System (INIS)

    Gueell, F.; Mateos, X.; Gavalda, Jna.; Sole, R.; Aguilo, M.; Diaz, F.; Massons, J.

    2004-01-01

    Up-conversion blue emissions of trivalent thulium ions in monoclinic KGd(WO 4 ) 2 single crystals at 454 and 479 nm are reported for a single pump laser source at 688 nm. We grew thulium-doped KGd(WO 4 ) 2 single crystals at several concentrations from 0.1% to 10%. We recorded a polarized optical absorption spectrum for the 3 F 2 + 3 F 3 energy levels of thulium at room temperature and low temperature (6 K). From the low temperature emission spectra we determined the splitting of the 3 H 6 ground state. The blue emissions are characterized as a function of the dopant concentration and temperature from 10 K to room temperature. To our knowledge, this is the first time that sequential two-photon excitation process (STEP) generated blue emissions in thulium-doped single crystals with a single excitation wavelength

  15. Tailoring the optical constants in single-crystal silicon with embedded silver nanostructures for advanced silicon photonics applications

    International Nuclear Information System (INIS)

    Akhter, Perveen; Huang, Mengbing; Spratt, William; Kadakia, Nirag; Amir, Faisal

    2015-01-01

    Plasmonic effects associated with metal nanostructures are expected to hold the key to tailoring light emission/propagation and harvesting solar energy in materials including single crystal silicon which remains the backbone in the microelectronics and photovoltaics industries but unfortunately, lacks many functionalities needed for construction of advanced photonic and optoelectronics devices. Currently, silicon plasmonic structures are practically possible only in the configuration with metal nanoparticles or thin film arrays on a silicon surface. This does not enable one to exploit the full potential of plasmonics for optical engineering in silicon, because the plasmonic effects are dominant over a length of ∼50 nm, and the active device region typically lies below the surface much beyond this range. Here, we report on a novel method for the formation of silver nanoparticles embedded within a silicon crystal through metal gettering from a silver thin film deposited at the surface to nanocavities within the Si created by hydrogen ion implantation. The refractive index of the Ag-nanostructured layer is found to be 3–10% lower or higher than that of silicon for wavelengths below or beyond ∼815–900 nm, respectively. Around this wavelength range, the optical extinction values increase by a factor of 10–100 as opposed to the pure silicon case. Increasing the amount of gettered silver leads to an increased extinction as well as a redshift in wavelength position for the resonance. This resonance is attributed to the surface plasmon excitation of the resultant silver nanoparticles in silicon. Additionally, we show that the profiles for optical constants in silicon can be tailored by varying the position and number of nanocavity layers. Such silicon crystals with embedded metal nanostructures would offer novel functional base structures for applications in silicon photonics, optoelectronics, photovoltaics, and plasmonics

  16. Studies on the growth and characterization of tris (glycine) calcium({Iota}{Iota}) dichloride-a nonlinear optical crystal

    Energy Technology Data Exchange (ETDEWEB)

    Dhanaraj, P.V. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Rajesh, N.P., E-mail: rajeshnp@ssn.edu.i [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India)

    2011-01-01

    A systematic characterization of a novel nonlinear optical material tris (glycine) calcium({Iota}{Iota}) dichloride (TGCC) is performed. The solubility and metastable zone width of TGCC were studied. TGCC single crystal of dimensions 34x23x5 mm{sup 3} was grown by the slow evaporation technique. Single crystal X-ray diffraction studies reveal that the crystal belongs to orthorhombic system. Energy dispersive X-ray analysis confirms the presence of elements in the crystal. Structural perfection of the as-grown single crystal was studied through multicrystal X-ray diffraction analysis. The thermal characteristics of TGCC were analyzed by thermogravimetric and differential thermal analysis and differential scanning calorimetry. The transmittance of TGCC crystal has been used to calculate the optical band gap of the crystal. Chemical etching studies of TGCC crystal was carried out. The dielectric and mechanical behavior of the crystals were analyzed. The second harmonic conversion property of TGCC was identified by the Kurtz and Perry powder technique and was observed to be higher than that of KDP.

  17. A luminescence-optical spectroscopy study of Rb2KTiOF5 single crystals

    Science.gov (United States)

    Pustovarov, V. A.; Ogorodnikov, I. N.; Kozlov, A. V.; Isaenko, L. I.

    2018-06-01

    Large single crystals of Rb2KTiOF5 (RKTF), grown by slow solidification method, were studied (7-400 K) for various types of optical and radiation effects. The optical absorption spectra, the parameters of the Urbach rule at 293 K (σ = 0.24 and EU = 105 meV), the low-temperature reflection spectra (T = 7 K, E = 3.7-22 eV) were determined. The luminescence spectra (1.2-6.2 eV) and luminescence decay kinetics are studied upon excitation by a nanosecond electron beam (PCL), ultraviolet and vacuum ultraviolet light (PL), or X-rays radiation (XRL). PL excitation spectra under selective photoexcitation by synchrotron radiation (E = 3.7-22 eV, T = 7 K), temperature dependences of the intensity of steady-state XRL in different emission bands, as well as thermoluminescence (7-400 K) are studied. In the visible spectral region, we detected three luminescence bands that were attributed to radiative annihilation of intrinsic excitons (2.25 eV), recombination-type luminescence (2.1 eV) and luminescence of higher TiOF5 complexes (1.9 eV). The exponential component with lifetime of about 19 μs was revealed in the PCL decay kinetics at 2.25 eV. The low-energy onset of the intrinsic host absorption Ec = 3.55 eV was determined on the basis of the experimental data obtained. Spectra of optical constants were calculated by the Kramers-Krönig method, the energy of the onset of the interband transitions Eg = 4.2 eV was determined, and the main peaks of the optical spectra were identified.

  18. Ultrafast Single-Shot Optical Oscilloscope based on Time-to-Space Conversion due to Temporal and Spatial Walk-Off Effects in Nonlinear Mixing Crystal

    Science.gov (United States)

    Takagi, Yoshihiro; Yamada, Yoshifumi; Ishikawa, Kiyoshi; Shimizu, Seiji; Sakabe, Shuji

    2005-09-01

    A simple method for single-shot sub-picosecond optical pulse diagnostics has been demonstrated by imaging the time evolution of the optical mixing onto the beam cross section of the sum-frequency wave when the interrogating pulse passes over the tested pulse in the mixing crystal as a result of the combined effect of group-velocity difference and walk-off beam propagation. A high linearity of the time-to-space projection is deduced from the process solely dependent upon the spatial uniformity of the refractive indices. A snap profile of the accidental coincidence between asynchronous pulses from separate mode-locked lasers has been detected, which demonstrates the single-shot ability.

  19. Synthesis, growth, morphology and characterization of ferroelectric glycine phosphite single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Devi, K. Renuka; Srinivasan, K. [Crystal Growth Laboratory, Department of Physics, School of Physical Sciences, Bharathiar University, Tamil Nadu (India)

    2011-12-15

    Glycine phosphite (NH{sub 3}CH{sub 2}COO.H{sub 3}PO{sub 3}), a potential ferroelectric material, was grown as single crystals from aqueous solutions by slow evaporation and slow cooling methods. Laboratory synthesized title compound was purified by recrystallization method and confirmed by Fourier transform infrared and Laser Raman studies. Temperature dependent solubility in double distilled water in the range between 288 and 328 K was determined by gravimetric method. Morphological importance of various growth faces were studied by optical goniometry. Powder x-ray diffraction study performed on the grown crystals confirms the crystal system and lattice parameters of the unit cell. Optical transparency of the grown crystals in the ultraviolet-visible -near infrared region was studied by spectroscopic method. Thermal stability of the grown crystals in the temperature region above ambient until melting was studied using differential scanning calorimetry. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Controlling material birefringence in sapphire via self-assembled, sub-wavelength defects

    Science.gov (United States)

    Singh, Astha; Sharma, Geeta; Ranjan, Neeraj; Mittholiya, Kshitij; Bhatnagar, Anuj; Singh, B. P.; Mathur, Deepak; Vasa, Parinda

    2018-02-01

    Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. Generally, this is an intrinsic optical property of a material and cannot be altered. Here, we report a novel technique—direct laser writing—that enables us to control the natural, material birefringence of sapphire over a broad range of wavelengths. The broadband form birefringence originating from self-assembled, periodic array of sub-wavelength (˜ 50-200 nm) defects created by laser writing, can enhance, suppress or maintain the material birefringence of sapphire without affecting its transparency range in visible or its surface quality.

  1. Effect of Nickel sulphate on Growth, Structural, Optical, Mechanical and thermal properties of L-alanine Single Crystals (LANS)

    Science.gov (United States)

    Jothimani, R.; Selvarajan, P.

    2017-08-01

    The nonlinear optical materials find excellent place in frequency conversion, optical telecommunication, image processing, optical computing, and data storage. Due to possessing chiral symmetry and nature of crystallize in noncentro-symmetric space groups, the amino acids are applicable in NLO applications. A transparent nickel sulphate admixtured L-alanine crystal has been developed by solution method. X ray diffraction analysis depicts the orthorhombic crystal system of the sample. NLO efficiency of the sample was found to be highly pronounced compare to KDP. An enhanced linear optical property of the sample shows its suitability for NLO applications. Thermal behaviour of the sample was found by TGA/DTA analysis. Hardness parameters were also found for the sample by microhardness measurements. Laser damage threshold were also measured using Nd: YAG laser.

  2. Process development and characterization of centrosymmetric semiorganic nonlinear optical crystal: 4-dimethylaminopyridine potassium chloride

    Science.gov (United States)

    Johnson, J.; Srineevasan, R.; Sivavishnu, D.

    2018-06-01

    Centrosymmetric semiorganic crystal 4-dimethylaminopyridine potassium chloride (4-DMAPKC) has been grown successfully by using slow evaporation solution growth technique. Powder x-ray diffraction shows the 4-DMAPKC crystal has good crystalline nature. Single crystal XRD shows that the grown 4-DMAPKC is cubic crystal system with cell parameters a = 3.09 Å, b = 3.09 Å, c = 3.09 Å. Investigation has been carried out to assign the Vibrational frequencies of the grown crystal by FTIR spectral studies. UVsbnd Visible NIR optical absorption spectral studies in the range of 200-1100 nm shows low absorption in UVsbnd Visible region with lower cutoff wave length at 261 nm and optical band gap energy was found as Eg = 5.52 eV. Optically transmittance spectral shows 4-DMAPKC crystal is very good transparency in UV-Visible NIR region. Thermogravimetry and differential thermal (TG-DTA) analysis were carried out. Dielectric studies of as grown crystal sample exhibit low dielectric constant and loss at higher frequencies and attests the nonlinear optical activity. Micro hardness studies of as grown crystal were discussed. Second harmonic generation (SHG) efficiency of the 4-DMAPKC is 0.69 times as that of KDP.

  3. Growth, spectral, linear and nonlinear optical characteristics of an efficient semiorganic acentric crystal: L-valinium L-valine chloride

    Energy Technology Data Exchange (ETDEWEB)

    Nageshwari, M.; Jayaprakash, P.; Kumari, C. Rathika Thaya [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604407, Tamil Nadu (India); Vinitha, G. [Department of Physics, School of Advanced Sciences, VIT Chennai, 600127 Tamil Nadu (India); Caroline, M. Lydia, E-mail: lydiacaroline2006@yahoo.co.in [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604407, Tamil Nadu (India)

    2017-04-15

    An efficient nonlinear optical semiorganic material L-valinium L-valine chloride (LVVCl) was synthesized and grown-up by means of slow evaporation process. Single crystal XRD evince that LVVCl corresponds to monoclinic system having acentric space group P2{sub 1}. The diverse functional groups existing in LVVCl were discovered with FTIR spectral investigation. The UV-Visible and photoluminescence spectrum discloses the optical and electronic properties respectively for the grown crystal. Several optical properties specifically extinction coefficient, reflectance, linear refractive index, electrical and optical conductivity were also determined. The SEM analysis was also carried out and it portrayed the surface morphology of LVVCl. The calculated value of laser damage threshold was 2.59 GW/cm{sup 2}. The mechanical and dielectric property of LVVCl was investigated employing microhardness and dielectric studies. The second and third order nonlinear optical characteristics of LVVCl was characterized utilizing Kurtz Perry and Z scan technique respectively clearly suggest its suitability in the domain of optics and photonics. - Graphical abstract: Good quality transparent single crystals of L-valinium L-valine chloride single crystal was grown by slow evaporation technique. The grown crystals were analyzed using different instrumentation methods to check its usefulness for the device fabrication. The determination of nonlinear refractive index (n{sub 2}), absorption coefficient (β) and third order nonlinear susceptibility was determined by Z scan technique, highlighted that LVVCl can serve as a promising candidate for opto electronic and nonlinear optical applications.

  4. Inside Perovskites: Quantum Luminescence from Bulk Cs4PbBr6 Single Crystals

    KAUST Repository

    de Bastiani, Michele

    2017-08-01

    Zero-dimensional perovskite-related structures (0D-PRS) are a new frontier of perovskite-based materials. 0D-PRS, commonly synthesized in powder form, manifest distinctive optical properties such as strong photoluminescence (PL), narrow emission linewidth, and high exciton binding energy. These properties make 0D-PRS compelling for several types of optoelectronic applications, including phosphor screens and electroluminescent devices. However, it would not be possible to rationally design the chemistry and structure of these materials, without revealing the origins of their optical behaviour, which is contradictory to the well-studied APbX3 perovskites. In this work, we synthesize single crystals of Cs4PbBr6 0D-PRS, and investigated the origins of their unique optical and electronic properties. The crystals exhibit a PL quantum yield higher than 40%, the highest reported for perovskite-based single crystals. Time-resolved and temperature dependent PL studies, supported by DFT calculations, and structural analysis, elucidate an emissive behaviour reminiscent of a quantum confined structure rather than a typical bulk perovskite material.

  5. Acousto-optical interaction of surface acoustic and optical waves in a two-dimensional phoxonic crystal hetero-structure cavity.

    Science.gov (United States)

    Ma, Tian-Xue; Zou, Kui; Wang, Yue-Sheng; Zhang, Chuanzeng; Su, Xiao-Xing

    2014-11-17

    Phoxonic crystal is a promising material for manipulating sound and light simultaneously. In this paper, we theoretically demonstrate the propagation of acoustic and optical waves along the truncated surface of a two-dimensional square-latticed phoxonic crystal. Further, a phoxonic crystal hetero-structure cavity is proposed, which can simultaneously confine surface acoustic and optical waves. The interface motion and photoelastic effects are taken into account in the acousto-optical coupling. The results show obvious shifts in eigenfrequencies of the photonic cavity modes induced by different phononic cavity modes. The symmetry of the phononic cavity modes plays a more important role in the single-phonon exchange process than in the case of the multi-phonon exchange. Under the same deformation, the frequency shift of the photonic transverse electric mode is larger than that of the transverse magnetic mode.

  6. Non-Linear Optical Studies On Sol-Gel Derived Lead Chloride Crystals Using Z-Scan Technique

    OpenAIRE

    Rejeena, I; Lillibai, B; Toms, Roseleena; Nampoori, VP N; Radhakrishnan, P

    2014-01-01

    In this paper we report the preparation, optical characterization and non linear optical behavior of pure lead chloride crystals. Lead chloride samples subjected to UV and IR irradiation and electric and magnetic fields have also been investigated Optical nonlinearity in these lead chloride samples were determined using single beam and high sensitive Z-scan technique. Non linear optical studies of these materials in single distilled water show reverse saturable absorption which makes th...

  7. Optical and electrical properties of ZrSe3 single crystals grown by ...

    Indian Academy of Sciences (India)

    Unknown

    The optical band gap ... The indirect as well as direct band gap of ZrSe3 were found to be 1⋅1 eV and 1⋅47 eV, respec- ... solar cell studies have attracted attention of crystal grow- ers. .... shown in figures 1 and 2, it is possible to determine the.

  8. Optical and magneto-optical properties of single crystals of RFe{sub 2} (R = Gd, Tb, Ho, and Lu) and GdCo{sub 2} intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.J.

    1999-02-12

    The author has studied the diagonal and off-diagonal optical conductivity of RFe{sub 2}(R = Gd, Tb, Ho, Lu) and GdCo{sub 2} single crystals grown by the flux method. Using spectroscopic ellipsometry the author has measured the dielectric function from 1.5 to 5.5 eV. The magneto-optical Kerr spectrometer at temperatures between 7 and 295 K and applied magnetic fields between 0.5 to 1.6 T. The apparatus and calibration method are described in detail. Using magneto-optical data and optical constants he derives the experimental value of the off-diagonal conductivity components. Theoretical calculations of optical conductivities and magneto-optical parameters were performed using the tight binding-linear muffin tin orbitals method within the local spin density approximation. He applied this TB-LMTO method to LuFe{sub 2}. The theoretical results obtained agree well with the experimental data. The oxidation effects on the diagonal part of the optical conductivity were considered using a three-phase model. The oxidation effects on the magneto-optical parameters were also considered by treating the oxide layer as a nonmagnetic thin transparent layer. These corrections change not only the magnitude but also the shape of the optical conductivity and the magneto-optical parameters.

  9. Structural, mechanical, electrical and optical properties of a new lithium boro phthalate NLO crystal synthesized by a slow evaporation method

    Science.gov (United States)

    Mohanraj, K.; Balasubramanian, D.; Jhansi, N.

    2017-11-01

    A new non-linear optical (NLO) single crystal of lithium boro phthalate (LiBP) was grown by slow solvent evaporation technique. The powder sample was subjected to powder X-ray diffraction (PXRD) to find its crystalline nature and the crystal structure of the grown crystal was determined using single crystal X-ray (SXRD) diffraction analysis. The Fourier Transform Infrared (FTIR) spectrum was recorded for grown crystal to identify the various functional groups present in the compound. The mechanical property of the LiBP single crystal was studied using Vickers microhardness tester. The dielectric constant and dielectric loss measurements were carried out for the grown crystal at various temperatures. The grown crystal was subjected to UV-Visible Spectral Studies to analyze the linear optical behavior of the grown crystal. The Kurtz-Perry Powder technique was employed to measure the Second Harmonic Generation efficiency of the grown crystal.

  10. Crystal growth and mechanical hardness of In{sub 2}Se{sub 2.7}Sb{sub 0.3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Piyush, E-mail: piyush-patel130@yahoo.com; Vyas, S. M., E-mail: s-m-vyas-gu@hotmail.com; Patel, Vimal; Pavagadhi, Himanshu [Department of Physics, School of Science, Gujarat University, Ahmedabad, Gujarat, India-380009 (India); Solanki, Mitesh [panditdindayal Petroleum University, Gandhinagar. Gujarat (India); Jani, Maunik P. [BITS Edu Campus, Varnama, Vadodara, Gujarat (India)

    2015-08-28

    The III-VI compound semiconductors is important for the fabrication of ionizing radiation detectors, solid-state electrodes, and photosensitive heterostructures, solar cell and ionic batteries. In this paper, In{sub 2}Se{sub 2.7} Sb{sub 0.3} single crystals were grown by the Bridgman method with temperature gradient of 60 °C/cm and the growth velocity 0.5cm/hr. The as-grown crystals were examined under the optical microscope for surface study, a various growth features observed on top free surface of the single crystal which is predominant of layers growth mechanism. The lattice parameters of as-grown crystal was determined by the XRD analysis. A Vickers’ projection microscope were used for the study of microhardness on the as-cleaved, cold-worked and annealed samples of the crystals, the results were discussed, and reported in detail.

  11. single crystal growth, x-ray structure analysis, optical band gap

    African Journals Online (AJOL)

    2015-09-01

    Sep 1, 2015 ... Hg...Hgand Cl...Cl interactions are stabilizing the structures in 3D pattern. UV-vis absorption spectra illustrate the change in opticalband gap from 3.01eVto 3.42eV on replacing the metal halide group.Raman and Hyper-Raman tensors calculations were performed based on single crystal X-ray data and the ...

  12. REVIEW: Optics of globular photonic crystals

    Science.gov (United States)

    Gorelik, V. S.

    2007-05-01

    The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ~200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported.

  13. A diamond-anvil high-pressure cell for X-ray diffraction on a single crystal

    International Nuclear Information System (INIS)

    Malinowski, M.

    1987-01-01

    A new diamond-anvil high-pressure cell is described which can be used in single-crystal X-ray diffraction instruments to collect X-ray intensity data from single-crystal samples up to hydrostatic pressures of about 10 GPa. A unique design allows two types of diffraction geometry to be applied in single-crystal high-pressure diffraction experiments. More than 85% of the Ewald sphere is accessible, and a continuous range of 2θ values is available from 0 up to about 160 0 . Pressure may be calibrated by the ruby fluorescence technique or by the use of an internal X-ray-standard single crystal. The design of our diamond-anvil cell would allow, with little or no modification, operation at high and low temperatures, optical studies and powder diffractometer work. (orig.)

  14. 5-nJ Femtosecond Ti3+:sapphire laser pumped with a single 1 W green diode

    Science.gov (United States)

    Muti, Abdullah; Kocabas, Askin; Sennaroglu, Alphan

    2018-05-01

    We report a Kerr-lens mode-locked, extended-cavity femtosecond Ti3+:sapphire laser directly pumped at 520 nm with a 1 W AlInGaN green diode. To obtain energy scaling, the short x-cavity was extended with a q-preserving multi-pass cavity to reduce the pulse repetition rate to 5.78 MHz. With 880 mW of incident pump power, we obtained as high as 90 mW of continuous-wave output power from the short cavity by using a 3% output coupler. In the Kerr-lens mode-locked regime, the extended cavity produced nearly transform-limited 95 fs pulses at 776 nm. The resulting energy and peak power of the pulses were 5.1 nJ and 53 kW, respectively. To our knowledge, this represents the highest pulse energy directly obtained to date from a mode-locked, single-diode-pumped Ti3+:sapphire laser.

  15. Optical and magneto-optical properties of the electron-doped and hole-doped C{sub 82} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Rostampour, E., E-mail: el_rostampour@yahoo.com [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Koohi, A. [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, Tehran (Iran, Islamic Republic of)

    2015-01-15

    The optical and magnetic properties of the doped C{sub 82} crystal have been investigated by Su–Schrieffer–Heeger (SSH) model, which is based on the Ewald method. When the C{sub 82} molecule is doped with one electron (or hole), a single electron is remained in the energy level that affects the optical and magnetic properties of the C{sub 82} crystal. The lattice and electronic structures of C{sub 82} changed with doping electron (or hole) in the molecule of C{sub 82}. Therefore, polarons are predicted in doped fullerenes. The obtained results showed that the dielectric tensor of the C{sub 82} crystal increased with doping electron (or hole) in the molecule of C{sub 82}. The spectral shapes of the dielectric tensor, circular dichroism and birefringence coefficient of the C{sub 82} crystal turn out to be determined mainly by the geometrical distributions of the pentagons in the fullerene structures.

  16. Non-destructive local determination of doping additions and main components in single crystals

    International Nuclear Information System (INIS)

    Ehksperiandova, L.P.; Blank, A.B.; Kukhtina, N.N.; Afanasiadi, L.I.

    1994-01-01

    Procedures for local non-destructive determination of elements in optical and scintillation single crystals are developed. They are applied for determination of the main components (in cadmium tungstate) and doping additions (tellurium in zinc selenide, europium in gadolinium silicate). The metrological characteristics of the developed micro-analysis methods are estimated. Segregation of the main components and doping additions in the objects under consideration are investigated. Tellurium is found to be distributed uniformly on the cross-sections of bulk zinc selenide single crystals. The segregation of europium along gadolinium silicate ingots is almost absent. On the cross-section surface of cadmium tungstate single crystals the microregions are found characterized by the prevailing contents of cadmium or tungsten

  17. Demonstration of frequency control and CW diode laser injection control of a titanium-doped sapphire ring laser with no internal optical elements

    Science.gov (United States)

    Bair, Clayton H.; Brockman, Philip; Hess, Robert V.; Modlin, Edward A.

    1988-01-01

    Theoretical and experimental frequency narrowing studies of a Ti:sapphire ring laser with no intracavity optical elements are reported. Frequency narrowing has been achieved using a birefringent filter between a partially reflecting reverse wave suppressor mirror and the ring cavity output mirror. Results of CW diode laser injection seeding are reported.

  18. Growth of rare-earth doped single crystal yttrium aluminum garnet fibers

    Science.gov (United States)

    Bera, Subhabrata; Nie, Craig D.; Harrington, James A.; Cheng, Long; Rand, Stephen C.; Li, Yuan; Johnson, Eric G.

    2018-02-01

    Rare-earth doped single crystal (SC) yttrium aluminum garnet (YAG) fibers have great potential as high-power laser gain media. SC fibers combine the superior material properties of crystals with the advantages of a fiber geometry. Improving processing techniques, growth of low-loss YAG SC fibers have been reported. A low-cost technique that allows for the growth of optical quality Ho:YAG single crystal (SC) fibers with different dopant concentrations have been developed and discussed. This technique is a low-cost sol-gel based method which offers greater flexibility in terms of dopant concentration. Self-segregation of Nd ions in YAG SC fibers have been observed. Such a phenomenon can be utilized to fabricate monolithic SC fibers with graded index.

  19. Solid-state reaction kinetics and optical studies of cadmium doped magnesium hydrogen phosphate crystals

    Science.gov (United States)

    Verma, Madhu; Gupta, Rashmi; Singh, Harjinder; Bamzai, K. K.

    2018-04-01

    The growth of cadmium doped magnesium hydrogen phosphate was successfully carried out by using room temperature solution technique i.e., gel encapsulation technique. Grown crystals were confirmed by single crystal X-ray diffraction (XRD). The structure of the grown crystal belongs to orthorhombic crystal system and crystallizes in centrosymmetric space group. Kinetics of the decomposition of the grown crystals were studied by non-isothermal analysis. Thermo gravimetric / differential thermo analytical (TG/DTA) studies revealed that the grown crystal is stable upto 119 °C. The various steps involved in the thermal decomposition of the material have been analysed using Horowitz-Metzger, Coats-Redfern and Piloyan-Novikova equations for evaluating various kinetic parameters. The optical studies shows that the grown crystals possess wide transmittance in the visible region and significant optical band gap of 5.5ev with cut off wavelength of 260 nm.

  20. Perovskite single crystals and thin films for optoelectronic devices (Conference Presentation)

    Science.gov (United States)

    Li, Gang; Han, Qifeng; Yang, Yang; Bae, Sang-Hoon; Sun, Pengyu

    2016-09-01

    Hybrid organolead trihalide perovskite (OTP) solar cells have developed as a promising candidate in photovoltaics due to their excellent properties including a direct bandgap, strong absorption coefficient, long carrier lifetime, and high mobility. Most recently, formamidinium (NH2CH=NH2+ or FA) lead iodide (FAPbI3) has attracted significant attention due to several advantages: (1) the larger organic FA cation can replace the MA cation and form a more symmetric crystal structure, (2) the smaller bandgap of FAPbI3 allows for near infrared (NIR) absorption, and (3) FAPbI3 has an elevated decomposition temperature and thus potential to improve stability. Single crystals provide an excellent model system to study the intrinsic electrical and optical properties of these materials due to their high purity, which is particularly important to understand the limits of these materials. In this work, we report the growth of large ( 5 millimeter size) single crystal FAPbI3 using a novel liquid based crystallization method. The single crystal FAPbI3 demonstrated a δ-phase to α-phase transition with a color change from yellow to black when heated to 185°C within approximately two minutes. The crystal structures of the two phases were identified and the PL emission peak of the α-phase FAPbI3 (820 nm) shows clear red-shift compared to the FAPbI3 thin film (805 nm). The FAPbI3 single crystal shows a long carrier lifetime of 484 ns, a high carrier mobility of 4.4 cm2·V-1·s-1, and even more interestingly a conductivity of 1.1 × 10-7(ohm·cm)-1, which is approximately one order of magnitude higher than that of the MAPbI3 single crystal. Finally, high performance photoconductivity type photodetectors were successfully demonstrated using the single crystal FAPbI3.

  1. Elastic properties of Ti-24Nb-4Zr-8Sn single crystals with bcc crystal structure

    International Nuclear Information System (INIS)

    Zhang, Y.W.; Li, S.J.; Obbard, E.G.; Wang, H.; Wang, S.C.; Hao, Y.L.; Yang, R.

    2011-01-01

    Research highlights: → The single crystals of Ti2448 alloy with the bcc crystal structure were prepared. → The elastic moduli and constants were measured by several resonant methods. → The crystal shows significant elastic asymmetry in tension and compression. → The crystal exhibits weak nonlinear elasticity with large elastic strain ∼2.5%. → The crystal has weak atomic interactions against crystal distortion to low symmetry. - Abstract: Single crystals of Ti2448 alloy (Ti-24Nb-4Zr-8Sn in wt.%) were grown successfully using an optical floating-zone furnace. Several kinds of resonant methods gave consistent Young's moduli of 27.1, 56.3 and 88.1 GPa and shear moduli of 34.8, 11.0 and 14.6 GPa for the , and oriented single crystals, and C 11 , C 12 and C 44 of 57.2, 36.1 and 35.9 GPa respectively. Uniaxial testing revealed asymmetrical elastic behaviors of the crystals: tension caused elastic softening with a large reversible strain of ∼4% and a stress plateau of ∼250 MPa, whereas compression resulted in gradual elastic stiffening with much smaller reversible strain. The crystals exhibited weak nonlinear elasticity with a large elastic strain of ∼2.5% and a high strength, approaching ∼20% and ∼30% of its ideal shear and ideal tensile strength respectively. The crystals showed linear elasticity with a small elastic strain of ∼1%. These elastic deformation characteristics have been interpreted in terms of weakened atomic interactions against crystal distortion to low crystal symmetry under external applied stresses. These results are consistent with the properties of polycrystalline Ti2448, including high strength, low elastic modulus, large recoverable strain and weak strengthening effect due to grain refinement.

  2. Synthesis and growth of single crystals of PrCl3

    International Nuclear Information System (INIS)

    Pei, Jen Shieh.

    1984-01-01

    An efficient method for growth of high optical quality single crystals of PrCl 3 . The method consists in careful drying of the hydrated chloride, PrCl 3 . 7H 2 O, with a protective atmosphere of anhydrous HCl and Ar. A subsequent growth was done by the zone melting technique. The hydrated chloride had prepared from dissolution of the oxide Pr 6 O 11 in hydrochloric acid. The grown crystals had characterized fluorescence and x-ray diffraction measurements. (Author) [pt

  3. Strong exciton-photon coupling in organic single crystal microcavity with high molecular orientation

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Kaname [Department of Electronics, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Yamashita, Kenichi, E-mail: yamasita@kit.ac.jp [Faculty of Electrical Engineering and Electronics, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Yanagi, Hisao [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Yamao, Takeshi; Hotta, Shu [Faculty of Materials Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan)

    2016-08-08

    Strong exciton-photon coupling has been observed in a highly oriented organic single crystal microcavity. This microcavity consists of a thiophene/phenylene co-oligomer (TPCO) single crystal laminated on a high-reflection distributed Bragg reflector. In the TPCO crystal, molecular transition dipole was strongly polarized along a certain horizontal directions with respect to the main crystal plane. This dipole polarization causes significantly large anisotropies in the exciton transition and optical constants. Especially the anisotropic exciton transition was found to provide the strong enhancement in the coupling with the cavity mode, which was demonstrated by a Rabi splitting energy as large as ∼100 meV even in the “half-vertical cavity surface emitting lasing” microcavity structure.

  4. Strong exciton-photon coupling in organic single crystal microcavity with high molecular orientation

    Science.gov (United States)

    Goto, Kaname; Yamashita, Kenichi; Yanagi, Hisao; Yamao, Takeshi; Hotta, Shu

    2016-08-01

    Strong exciton-photon coupling has been observed in a highly oriented organic single crystal microcavity. This microcavity consists of a thiophene/phenylene co-oligomer (TPCO) single crystal laminated on a high-reflection distributed Bragg reflector. In the TPCO crystal, molecular transition dipole was strongly polarized along a certain horizontal directions with respect to the main crystal plane. This dipole polarization causes significantly large anisotropies in the exciton transition and optical constants. Especially the anisotropic exciton transition was found to provide the strong enhancement in the coupling with the cavity mode, which was demonstrated by a Rabi splitting energy as large as ˜100 meV even in the "half-vertical cavity surface emitting lasing" microcavity structure.

  5. Strong exciton-photon coupling in organic single crystal microcavity with high molecular orientation

    International Nuclear Information System (INIS)

    Goto, Kaname; Yamashita, Kenichi; Yanagi, Hisao; Yamao, Takeshi; Hotta, Shu

    2016-01-01

    Strong exciton-photon coupling has been observed in a highly oriented organic single crystal microcavity. This microcavity consists of a thiophene/phenylene co-oligomer (TPCO) single crystal laminated on a high-reflection distributed Bragg reflector. In the TPCO crystal, molecular transition dipole was strongly polarized along a certain horizontal directions with respect to the main crystal plane. This dipole polarization causes significantly large anisotropies in the exciton transition and optical constants. Especially the anisotropic exciton transition was found to provide the strong enhancement in the coupling with the cavity mode, which was demonstrated by a Rabi splitting energy as large as ∼100 meV even in the “half-vertical cavity surface emitting lasing” microcavity structure.

  6. Single mode operation in a pulsed Ti:sapphire laser oscillator with a grazing-incidence four-mirror cavity

    CERN Document Server

    Ko, D K; Binks, D J; Gloster, L A W; King, T A

    1998-01-01

    We demonstrate stable single mode operation in a pulsed Ti:sapphire laser oscillator with a novel grazing-incidence four-mirror coupled cavity. This cavity consists of a grating, a gain medium, and four mirrors and, therefore, has a four-arm interferometer configuration. Through the interferometric effect, we could suppress the adjacent modes and obtain stable single mode operation with a bandwidth of < 200 MHz. We also have developed a general analysis of the laser modes and the threshold conditions for configuration and the experimental results agree well with the theoretical predictions.

  7. Low trap-state density and long carrier diffusion in organolead trihalide perovskite single crystals

    KAUST Repository

    Shi, Dong

    2015-01-29

    The fundamental properties and ultimate performance limits of organolead trihalide MAPbX3(MA = CH3NH3 +; X = Br- or I- ) perovskites remain obscured by extensive disorder in polycrystalline MAPbX3 films. We report an antisolvent vapor-assisted crystallization approach that enables us to create sizable crack-free MAPbX3 single crystals with volumes exceeding 100 cubic millimeters. These large single crystals enabled a detailed characterization of their optical and charge transport characteristics.We observed exceptionally low trap-state densities on the order of 109 to 1010 per cubic centimeter in MAPbX3 single crystals (comparable to the best photovoltaic-quality silicon) and charge carrier diffusion lengths exceeding 10 micrometers. These results were validated with density functional theory calculations.

  8. Low trap-state density and long carrier diffusion in organolead trihalide perovskite single crystals

    KAUST Repository

    Shi, Dong; Adinolfi, Valerio; Comin, Riccardo; Yuan, Mingjian; Alarousu, Erkki; Buin, Andrei K.; Chen, Yin; Hoogland, Sjoerd H.; Rothenberger, Alexander; Katsiev, Khabiboulakh; Losovyj, Yaroslav B.; Zhang, Xin; Dowben, Peter A.; Mohammed, Omar F.; Sargent, E. H.; Bakr, Osman

    2015-01-01

    The fundamental properties and ultimate performance limits of organolead trihalide MAPbX3(MA = CH3NH3 +; X = Br- or I- ) perovskites remain obscured by extensive disorder in polycrystalline MAPbX3 films. We report an antisolvent vapor-assisted crystallization approach that enables us to create sizable crack-free MAPbX3 single crystals with volumes exceeding 100 cubic millimeters. These large single crystals enabled a detailed characterization of their optical and charge transport characteristics.We observed exceptionally low trap-state densities on the order of 109 to 1010 per cubic centimeter in MAPbX3 single crystals (comparable to the best photovoltaic-quality silicon) and charge carrier diffusion lengths exceeding 10 micrometers. These results were validated with density functional theory calculations.

  9. Tunable top-down fabrication and functional surface coating of single-crystal titanium dioxide nanostructures and nanoparticles

    Science.gov (United States)

    Ha, Seungkyu; Janissen, Richard; Ussembayev, Yera Ye.; van Oene, Maarten M.; Solano, Belen; Dekker, Nynke H.

    2016-05-01

    Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile TiO2 nanocylinders tethered with individual DNA molecules for use as force- and torque-transducers in an optical torque wrench. These developments provide the means for increased exploitation of the superior material properties of single-crystal TiO2 at the nanoscale.Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile

  10. Trapping, manipulation and rapid rotation of NBD-C8 fluorescent single microcrystals in optical tweezers

    International Nuclear Information System (INIS)

    GALAUP, Jean-Pierre; RODRIGUEZ-OTAZO, Mariela; AUGIER-CALDERIN, Angel; LAMERE; Jean-Francois; FERY-FORGUES, Suzanne

    2009-01-01

    We have built an optical tweezers experiment based on an inverted microscope to trap and manipulate single crystals of micro or sub-micrometer size made from fluorescent molecules of 4-octylamino-7-nitrobenzoxadiazole (NBD-C8). These single crystals have parallelepiped shapes and exhibit birefringence properties evidenced through optical experiments between crossed polarizers in a polarizing microscope. The crystals are uniaxial with their optical axis oriented along their largest dimension. Trapped in the optical trap, the organic micro-crystals are oriented in such a way that their long axis is along the direction of the beam propagation, and their short axis follows the direction of the linear polarization. Therefore, with linearly polarized light, simply rotating the light polarization can orient the crystal. When using circularly or only elliptically polarized light, the crystal can spontaneously rotate and reach rotation speed of several hundreds of turns per second. A surprising result has been observed: when the incident power is growing up, the rotation speed increases to reach a maximum value and then decreases even when the power is still growing up. Moreover, this evolution is irreversible. Different possible explanations can be considered. The development of a 3D control of the crystals by dynamical holography using liquid crystal spatial modulators will be presented and discussed on the basis of the most recent results obtained. (Author)

  11. Ultraviolet laser-induced voltages in LaSrAlO4 single crystal

    International Nuclear Information System (INIS)

    Zhi-Qing, Lü; Kun, Zhao; Song-Qing, Zhao; Hui, Zhao; Qing-Li, Zhou

    2009-01-01

    Laser-induced ultrafast photovoltaic effect is observed in LaSrAlO 4 single crystal at ambient temperature without any applied bias. An open-circuit photovoltage is obtained when the wafer is irradiated by a 248-nm-KrF laser pulse of 20 ns duration. The response time and full width at half maximum of the photovoltage pulse are 6 ns and 19 ns, respectively, indicating that LaSrAlO 4 single crystal has potential application in ultraviolet detector. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  12. Single-crystal charge transfer interfaces for efficient photonic devices (Conference Presentation)

    Science.gov (United States)

    Alves, Helena; Pinto, Rui M.; Maçôas, Ermelinda M. S.; Baleizão, Carlos; Santos, Isabel C.

    2016-09-01

    Organic semiconductors have unique optical, mechanical and electronic properties that can be combined with customized chemical functionality. In the crystalline form, determinant features for electronic applications such as molecular purity, the charge mobility or the exciton diffusion length, reveal a superior performance when compared with materials in a more disordered form. Combining crystals of two different conjugated materials as even enable a new 2D electronic system. However, the use of organic single crystals in devices is still limited to a few applications, such as field-effect transistors. In 2013, we presented the first system composed of single-crystal charge transfer interfaces presenting photoconductivity behaviour. The system composed of rubrene and TCNQ has a responsivity reaching 1 A/W, corresponding to an external quantum efficiency of nearly 100%. A similar approach, with a hybrid structure of a PCBM film and rubrene single crystal also presents high responsivity and the possibility to extract excitons generated in acceptor materials. This strategy led to an extended action towards the near IR. By adequate material design and structural organisation of perylediimides, we demonstrate that is possible to improve exciton diffusion efficiency. More recently, we have successfully used the concept of charge transfer interfaces in phototransistors. These results open the possibility of using organic single-crystal interfaces in photonic applications.

  13. Diamond turning of small Fresnel lens array in single crystal InSb

    International Nuclear Information System (INIS)

    Jasinevicius, R G; Duduch, J G; Cirino, G A; Pizani, P S

    2013-01-01

    A small Fresnel lens array was diamond turned in a single crystal (0 0 1) InSb wafer using a half-radius negative rake angle (−25°) single-point diamond tool. The machined array consisted of three concave Fresnel lenses cut under different machining sequences. The Fresnel lens profiles were designed to operate in the paraxial domain having a quadratic phase distribution. The sample was examined by scanning electron microscopy and an optical profilometer. Optical profilometry was also used to measure the surface roughness of the machined surface. Ductile ribbon-like chips were observed on the cutting tool rake face. No signs of cutting edge wear was observed on the diamond tool. The machined surface presented an amorphous phase probed by micro Raman spectroscopy. A successful heat treatment of annealing was carried out to recover the crystalline phase on the machined surface. The results indicated that it is possible to perform a ‘mechanical lithography’ process in single crystal semiconductors. (paper)

  14. Spontaneous and stimulated emission in Sm3+-doped YAl3(BO3)4 single crystal

    International Nuclear Information System (INIS)

    Ryba-Romanowski, Witold; Lisiecki, Radosław; Beregi, Elena; Martín, I.R.

    2015-01-01

    Single crystals of YAl 3 (BO 3 ) 4 doped with trivalent samarium were grown by the top-seeded high temperature solution method and their absorption and emission spectra were investigated. Optical pumping into prominent absorption band around 405 nm feeds the 4 G 5/2 metastable level giving rise to intense visible luminescence distributed in several spectral lines with the most intense line around 600 nm characterized by a branching ratio of 0.42 and peak emission cross section of 0.25×10 −20 cm 2 . Optical amplification at 600 nm with a gain coefficient of 2.9 cm −1 was achieved during a pump-and-probe experiment. - Highlights: • YAB:Sm crystal grown by the top-seeded high temperature solution method. • Spectroscopic qualities relevant for visible laser operation. • YAB:Sm single crystal used in a pump-and-probe experiment. • Optical amplification properties of samarium doped YAl 3 (BO 3 ) 4

  15. Growth and optical properties of Tm:GdVO4 single crystal

    International Nuclear Information System (INIS)

    Urata, Y.; Akagawa, K.; Wada, S.; Tashiro, H.; Fukuda, T.

    1999-01-01

    Thulium-doped gadolinium vanadate (Tm:GdVO 4 ) single crystal has been successfully grown by a modified Czochralski (CZ) technique. Effective distribution coefficient of Tm was determined to be 0.74. Absorption characterization was performed in the 800 nm region and the maximum absorption peak was found at 799 nm for π polarization. Fluorescence spectra for tuning at the maximum absorption were obtained around 1.8-2.0 μm region with 100 nm bandwidth. This suggests that a Tm:GdVO 4 crystal is expected as a new promising LD pumped solid-state laser in the 2 μm region. (orig.)

  16. Infrared absorption in PbTe single crystals

    International Nuclear Information System (INIS)

    Kudykina, T.A.

    1982-01-01

    A group-theoretical analysis is conducted to select rules for optical transitions between bands in PbTe single crystals. It is shown that transitions between valence bands which are near a forbidden band are also forbidden. The extra absorption observed in p-PbTe and p-Pbsub(1-x)Snsub(x)Te in the region between the self-absorption edge and the free-carrier absorption edge is probably connected with transitions between one of valence bands and the p-state of the impurity

  17. Effect of amaranth on dielectric, thermal and optical properties of KDP single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chandran, Senthilkumar; Paulraj, Rajesh, E-mail: rajeshp@ssn.edu.in; Ramasamy, P.

    2017-01-15

    Bulk single crystals of pure and amaranth doped KDP were grown using point seed technique. Effect of amaranth doping on KDP crystals was analyzed using powder XRD, thermal analysis (TG/DTA), dielectric, photoconductivity and etching studies. The phase purity and crystallinity of pure and dye doped crystals were confirmed by powder X-ray diffraction analysis. It is observed from TG-DTA analysis that the decomposition point decreased while doping with amaranth. Dielectric constant and loss increases with increasing temperatures. The photoconductivity decreases with the increase of amaranth concentration. - Highlights: • Pure and amaranth doped KDP crystals grown from point seed technique. • The addition of amaranth changes the decomposition points of dye doped KDP crystals. • Dielectric constant is increased. • It shows positive photoconductivity.

  18. Transmittance enhancement of sapphires with antireflective subwavelength grating patterned UV polymer surface structures by soft lithography.

    Science.gov (United States)

    Lee, Soo Hyun; Leem, Jung Woo; Yu, Jae Su

    2013-12-02

    We report the total and diffuse transmission enhancement of sapphires with the ultraviolet curable SU8 polymer surface structures consisting of conical subwavelength gratings (SWGs) at one- and both-side surfaces for different periods. The SWGs patterns on the silicon templates were transferred into the SU8 polymer film surface on sapphires by a simple and cost-effective soft lithography technique. For the fabricated samples, the surface morphologies, wetting behaviors, and optical characteristics were investigated. For theoretical optical analysis, a rigorous coupled-wave analysis method was used. At a period of 350 nm, the sample with SWGs on SU8 film/sapphire exhibited a hydrophobic surface and higher total transmittance compared to the bare sapphire over a wide wavelength of 450-1000 nm. As the period of SWGs was increased, the low total transmittance region of < 85% was shifted towards the longer wavelengths and became broader while the diffuse transmittance was increased (i.e., larger haze ratio). For the samples with SWGs at both-side surfaces, the total and diffuse transmittance spectra were further enhanced compared to the samples with SWGs at one-side surface. The theoretical optical calculation results showed a similar trend to the experimentally measured data.

  19. Growth and characterization of new nonlinear optical 1-phenyl-3-(4-dimethylamino phenyl) prop-2-en-1-one (PDAC) single crystals

    Science.gov (United States)

    Ravindraswami, K.; Janardhana, K.; Gowda, Jayaprakash; Moolya, B. Narayana

    2018-04-01

    Non linear optical 1-phenyl-3-(4-dimethylamino phenyl) prop-2-en-1-one (PDAC) was synthesized using Claisen - Schmidt condensation method and studied for optical nonlinearity with an emphasis on structure-property relationship. The structural confirmation studies were carried out using 1H-NMR, FT-IR and single crystal XRD techniques. The nonlinear absorption and nonlinear refraction parameters in z-scan with nano second laser pulses were obtained by measuring the profile of propagated beam through the samples. The real and imaginary parts of third-order bulk susceptibility χ(3) were evaluated. Thermo gravimetric analysis is carried out to investigate the thermal stability.

  20. Ultrafast carrier dynamics in pentacene, functionalized pentacene, tetracene, and rubrene single crystals

    NARCIS (Netherlands)

    Ostroverkhova, O; Cooke, DG; Hegmann, FA; Anthony, JE; Podzorov, [No Value; Gershenson, ME; Jurchescu, OD; Palstra, TTM

    2006-01-01

    We measure the transient photoconductivity in pentacene, functionalized pentacene, tetracene, and rubrene single crystals using optical pump-terahertz probe techniques. In all of the samples studied, we observe subpicosecond charge photogeneration and a peak photoconductive response that increases

  1. Twinning behavior in the Ti-5at.% Al single crystals during cyclic loading along [0001

    International Nuclear Information System (INIS)

    Xiao Lin

    2005-01-01

    Cyclic deformation behavior of Ti-5at.% Al single crystals subjected to pull-push cyclic load along [0001] crystallographic orientation was studied. A higher cyclic stress response was displayed in the Ti-5Al single crystal oriented for [0001] than that oriented for single prism slip. Optical microscopy and transmission electron microscopy examinations show that twinning is a dominant plastic deformation mode in the single crystals during cycling. Trace analysis of prepolished surfaces was used to identify the twin systems primarily responsible for deformation. The major twin type observed was {101-bar 2}, {112-bar 2}, {101-bar 1} and {112-bar 1}. slip was observed in the neighboring region of twins in the fatigued specimens. The activation of multiple twinning systems contributed to the higher cyclic saturation stress in Ti-5Al single crystals oriented for [0001

  2. Growth and characterization of benzaldehyde 4-nitro phenyl hydrazone (BPH) single crystal: A proficient second order nonlinear optical material

    Science.gov (United States)

    Saravanan, M.; Abraham Rajasekar, S.

    2016-04-01

    The crystals (benzaldehyde 4-nitro phenyl hydrazone (BPH)) appropriate for NLO appliance were grown by the slow cooling method. The solubility and metastable zone width measurement of BPH specimen was studied. The material crystallizes in the monoclinic crystal system with noncentrosymmetric space group of Cc. The optical precision in the whole visible region was found to be excellent for non-linear optical claim. Excellence of the grown crystal is ascertained by the HRXRD and etching studies. Laser Damage Threshold and Photoluminescence studies designate that the grown crystal contains less imperfection. The mechanical behaviour of BPH sample at different temperatures was investigated to determine the hardness stability of the grown specimen. The piezoelectric temperament and the relative Second Harmonic Generation (for diverse particle sizes) of the material were also studied. The dielectric studies were executed at varied temperatures and frequencies to investigate the electrical properties. Photoconductivity measurement enumerates consummate of inducing dipoles due to strong incident radiation and also divulge the nonlinear behaviour of the material. The third order nonlinear optical properties of BPH crystals were deliberate by Z-scan method.

  3. Oxidation states of Fe and Ti in blue sapphire

    International Nuclear Information System (INIS)

    Wongrawang, P; Wongkokua, W; Monarumit, N; Thammajak, N; Wathanakul, P

    2016-01-01

    X-ray absorption near-edge spectroscopy (XANES) can be used to study the oxidation state of a dilute system such as transition metal defects in solid-state samples. In blue sapphire, Fe and Ti are defects that cause the blue color. Inter-valence charge transfer (IVCT) between Fe 2+ and Ti 4+ has been proposed to describe the optical color’s origin. However, the existence of divalent iron cations has not been thoroughly investigated. Fluorescent XANES is therefore employed to study K-edge absorptions of Fe and Ti cations in various blue sapphire samples including natural, synthetic, diffused and heat-treated sapphires. All the samples showed an Fe absorption edge at 7124 eV, corresponding to the Fe 3+ state; and Ti at 4984 eV, corresponding to Ti 4+ . From these results, we propose Fe 3+ -Ti 4+ mixed acceptor states located at 1.75 eV and 2.14 eV above the valence band of corundum, that correspond to 710 nm and 580 nm bands of UV–vis absorption spectra, to describe the cause of the color of blue sapphire. (paper)

  4. Ion implantation induced blistering of rutile single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Bing-Xi [School of Physics, Shandong University, Jinan, Shandong 250100 (China); Jiao, Yang [College of Physics and Electronics, Shandong Normal University, Jinan, Shandong 250100 (China); Guan, Jing [School of Physics, Shandong University, Jinan, Shandong 250100 (China); Wang, Lei [School of Physics, Shandong University, Jinan, Shandong 250100 (China); Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (China)

    2015-07-01

    The rutile single crystals were implanted by 200 keV He{sup +} ions with a series fluence and annealed at different temperatures to investigate the blistering behavior. The Rutherford backscattering spectrometry, optical microscope and X-ray diffraction were employed to characterize the implantation induced lattice damage and blistering. It was found that the blistering on rutile surface region can be realized by He{sup +} ion implantation with appropriate fluence and the following thermal annealing.

  5. Twinning processes in Cu-Al-Ni martensite single crystals investigated by neutron single crystal diffraction method

    International Nuclear Information System (INIS)

    Molnar, P.; Sittner, P.; Novak, V.; Lukas, P.

    2008-01-01

    A neutron single crystal diffraction method for inspecting the quality of martensite single crystals is introduced. True interface-free martensite single crystals are indispensable for, e.g. measurement of elastic constants of phases by ultrasonic techniques. The neutron diffraction method was used to detect and distinguish the presence of individual lattice correspondence variants of the 2H orthorhombic martensite phase in Cu-Al-Ni as well as to follow the activity of twinning processes during the deformation test on the martensite variant single crystals. When preparing the martensite single variant prism-shaped crystals by compression deformation method, typically a small fraction of second unwanted martensitic variant (compound twin) remains in the prism samples. Due to the very low stress (∼1 MPa) for the compound twinning in many shape memory alloys, it is quite difficult not only to deplete the martensite prisms of all internal interfaces but mainly to keep them in the martensite single variant state for a long time needed for further investigations

  6. Broadband multiplex coherent anti-Stokes Raman scattering microscopy employing photonic-crystal fibers

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn; Paulsen, Henrik Nørgaard; Birkedal, Victoria

    2006-01-01

    We demonstrate spectral multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy and microscopy based on a single Ti:sapphire oscillator and a nonlinear photonic-crystal fiber (PCF). The Stokes pulse is generated by spectral conversion of the laser pulse in a PCF. The pump pulse is eit...

  7. FT-IR reflection spectra of single crystals: resolving phonons of different symmetry without using polarised radiation

    Directory of Open Access Journals (Sweden)

    METODIJA NAJDOSKI

    2000-07-01

    Full Text Available Fourier-transform infrared (FT-IR reflection spectra, asquired at nearnormal incidence, were recorded from single crystals belonging to six crystal systems: CsCr(SO42.12H2O (alum, cubic, K2CuCl2·2H2O (Mitscherlichite, tetragonal, CaCO3 (calcite, hexagonal, KHSO4 (mercallite, orthorhombic, CaSO4·2H2O (gypsum, monoclinic and CuSO4·5H2O (chalcantite, triclinic. The acquired IR reflection spectra were further transformed into absorption spectra, employing the Kramers-Kronig transformation. Except for the cubic alums, the spectra strongly depend on the crystal face from which they were recorded; this is a consequence of anisotropy. Phonons of a given symmetry (E-species, in tetragonal/hexagonal and B-species, in monoclinic crystals may be resolved without using a polariser. The spectrum may be simplified in the case of an orthorhombic crystal, as well. The longitudinal-optical (LO and transversal-optical (TO mode frequencies were calculated in the case of optically isotropic and the simplified spectra of optically uniaxial crystals.

  8. Design and fabrication of single-crystal GaN nano-bridge on homogeneous substrate for nanoindentation

    Science.gov (United States)

    Hung, Shang-Chao

    2014-12-01

    This study reports a simple method to design and fabricate a freestanding GaN nano-bridge over a homogeneous short column as supporting leg. Test samples were fabricated from MOCVD-grown single-crystal GaN films over sapphire substrate using a FIB milling to leave freestanding short spans. We also investigated the nanoindentation characteristics and the corresponding nanoscopic mechanism of the GaN nano-bridge and its short column with a conical indenter inside transmission electron microscopy. The stress-strain mechanical properties and Young's modulus have also been examined and calculated as 108 GPa ± 4.8 % by the strain energy method. The significant slope switch of the L- D curve corresponds to the transition from the single-point bending indentation to the surface stretching indentation and has been interpreted with the evolution of TEM images. This freestanding fabrication and test have key advantages to characterize nanoscale behavior of one-dimensional bridge structure and greater ease of sample preparation over other micro-fabrication techniques.

  9. Giant coercivity in ferromagnetic Co doped ZnO single crystal thin film

    International Nuclear Information System (INIS)

    Loukya, B.; Negi, D.S.; Dileep, K.; Kumar, N.; Ghatak, Jay; Datta, R.

    2013-01-01

    The origin of ferromagnetism in ZnO doped with transition metal impurities has been discussed extensively and appeared to be a highly controversial and challenging topic in today's solid state physics. Magnetism observed in this system is generally weak and soft. We have grown Co:ZnO up to 30 at% Co in single crystal thin film form on c-plane sapphire. A composition dependent coercivity is observed in this system which reaches peak value at 25 at% Co, the values are 860 Oe and 1149 Oe with applied field along parallel and perpendicular to the film substrate interface respectively. This giant coercivity might pave the way to exploit this material as a magnetic semiconductor with novel logic functionalities. The findings are explained based on defect band itinerant ferromagnetism and its partial interaction with localized d electrons of Co through charge transfer. Besides large coercivity, an increase in the band gap with Co concentration has also been observed along with blue emission peak with long tail confirming the formation of extended point defect levels in the host lattice band gap. - Highlights: • Co doped ZnO ferromagnetic single crystal thin film. • Giant coercivity in Co:ZnO thin film which may help to turn this material into application. • Cathodoluminescence (CL) data showing increase in band gap with Co concentrations. • A theoretical proposal is made to explain the observed giant coercivity

  10. CsPb2Br5 Single Crystals: Synthesis and Characterization

    KAUST Repository

    Dursun, Ibrahim

    2017-08-02

    CsPb2Br5 is a ternary halogen-plumbate material with close characteristics to well-reported halide perovskites. Due to its unconventional two-dimensional structure, CsPb2Br5 is being looked at broadly for potential applications in optoelectronics. CsPb2Br5 investigations are currently limited to nanostructures and powder forms of the material, which present unclear and conflicting optical properties. In this study, we present the synthesis and characterization of CsPb2Br5 bulk single crystals, which enabled us to finally clarify the material\\'s optical features. Our CsPb2Br5 crystal has a two-dimensional structure with Pb2Br5- layers spaced by Cs+ cations, and exhibits a ~3.1 eV indirect bandgap with no emission in the visible spectrum.

  11. Properties of melt-grown single crystals of 'YB/sub 68/'

    Energy Technology Data Exchange (ETDEWEB)

    Slack, G A; Oliver, D W; Brower, G D; Young, J D [General Electric Co., Schenectady, N.Y. (USA). Research and Development Center

    1977-01-01

    Single crystals of yttrium boride YB/sub n/ with n = 61 +- 3 were grown from the melt. Precision density and lattice parameter measurements indicate a congruent melting point at n = 61.7 and a stoichiometric composition at n = 68. Measurements of elastic constants, acoustic attenuation, electrical resistivity and optical absorption are presented. High resolution transmission electron microscopy reveals a complex crystal structure similar to that found by using X-rays. A comparison of the properties of YB/sub n/ with those of ..beta..-boron show that there are many similarities.

  12. Growth and optical microscopy observation of the lysozyme crystals

    OpenAIRE

    R.Vlokh; L.Marsel; I.Teslyuk; O.G.Vlokh

    2001-01-01

    The little single lysozyme crystals in the capillary after 15 days of growth process with average size 0.1´0.1´0.16mm3 were obtained. It was shown that lysozyme crystals are optically anisotropical and birefringence along a axis is Dn=(2.2±0.5)´10-3 in visible spectrum region. From the measurements of crystallographic angles follows that on the {001} faces angles equal a=81o, b=99o. On the sexangle faces angles equal e=100o, f=140o and g=120o. On the base of obtained results the lysozyme crys...

  13. Synthesis, growth, morphology of the semiorganic nonlinear optical crystal L-glutamic acid hydrochloride and its structural, thermal and SHG characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Dhanasekaran, P.; Srinivasan, K. [Crystal Growth Laboratory, Department of Physics, School of Physical Sciences, Bharathiar University, Coimbatore-641 046, Tamil Nadu (India)

    2012-12-15

    One of the halide derivatives of L-glutamic acid which was identified as a semiorganic nonlinear optical material, L-glutamic acid hydrochloride [HOOC(CH{sub 2}){sub 2}CH(NH{sub 2})COOH.HCl], was grown as bulk single crystal and its significant properties were characterized. The stoichiometric title compound was synthesized and the solubility of its recrystallized form in DD water was determined in the temperature range 30-80 C by gravimetric method. Structural confirmation was carried out by powder X-ray diffraction study through lattice parameter verification. Optical quality smaller dimension single crystals were grown from aqueous solution by self nucleation through slow evaporation of solvent method and a large dimension single crystal was grown by slow cooling method with reversible seed rotation technique. Morphological importances of different growth facets of the as grown crystals were studied through optical goniometry. Unit cell structure of the grown crystal was refined by single crystal X-ray diffraction analysis, functional groups present in the crystal responsible for various modes of vibrations were confirmed by FTIR spectroscopy analysis, thermal stability of the grown crystal was analysed by TG/DTA and DSC and second harmonic generation (SHG) of a fundamental Nd:YAG laser beam by Kurtz technique. Results indicate that the grown crystal is in stoichiometric composition and has significant improvement in its thermal and SHG properties when compared to pure L-glutamic acid polymorphs. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Ensembles of indium phosphide nanowires: physical properties and functional devices integrated on non-single crystal platforms

    International Nuclear Information System (INIS)

    Kobayashi, Nobuhiko P.; Lohn, Andrew; Onishi, Takehiro; Mathai, Sagi; Li, Xuema; Straznicky, Joseph; Wang, Shih-Yuan; Williams, R.S.; Logeeswaran, V.J.; Islam, M.S.

    2009-01-01

    A new route to grow an ensemble of indium phosphide single-crystal semiconductor nanowires is described. Unlike conventional epitaxial growth of single-crystal semiconductor films, the proposed route for growing semiconductor nanowires does not require a single-crystal semiconductor substrate. In the proposed route, instead of using single-crystal semiconductor substrates that are characterized by their long-range atomic ordering, a template layer that possesses short-range atomic ordering prepared on a non-single-crystal substrate is employed. On the template layer, epitaxial information associated with its short-range atomic ordering is available within an area that is comparable to that of a nanowire root. Thus the template layer locally provides epitaxial information required for the growth of semiconductor nanowires. In the particular demonstration described in this paper, hydrogenated silicon was used as a template layer for epitaxial growth of indium phosphide nanowires. The indium phosphide nanowires grown on the hydrogenerated silicon template layer were found to be single crystal and optically active. Simple photoconductors and pin-diodes were fabricated and tested with the view towards various optoelectronic device applications where group III-V compound semiconductors are functionally integrated onto non-single-crystal platforms. (orig.)

  15. Ensembles of indium phosphide nanowires: physical properties and functional devices integrated on non-single crystal platforms

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Nobuhiko P.; Lohn, Andrew; Onishi, Takehiro [University of California, Santa Cruz (United States). Baskin School of Engineering; NASA Ames Research Center, Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, Univ. of California Santa Cruz, Moffett Field, CA (United States); Mathai, Sagi; Li, Xuema; Straznicky, Joseph; Wang, Shih-Yuan; Williams, R.S. [Hewlett-Packard Laboratories, Information and Quantum Systems Laboratory, Palo Alto, CA (United States); Logeeswaran, V.J.; Islam, M.S. [University of California Davis, Electrical and Computer Engineering, Davis, CA (United States)

    2009-06-15

    A new route to grow an ensemble of indium phosphide single-crystal semiconductor nanowires is described. Unlike conventional epitaxial growth of single-crystal semiconductor films, the proposed route for growing semiconductor nanowires does not require a single-crystal semiconductor substrate. In the proposed route, instead of using single-crystal semiconductor substrates that are characterized by their long-range atomic ordering, a template layer that possesses short-range atomic ordering prepared on a non-single-crystal substrate is employed. On the template layer, epitaxial information associated with its short-range atomic ordering is available within an area that is comparable to that of a nanowire root. Thus the template layer locally provides epitaxial information required for the growth of semiconductor nanowires. In the particular demonstration described in this paper, hydrogenated silicon was used as a template layer for epitaxial growth of indium phosphide nanowires. The indium phosphide nanowires grown on the hydrogenerated silicon template layer were found to be single crystal and optically active. Simple photoconductors and pin-diodes were fabricated and tested with the view towards various optoelectronic device applications where group III-V compound semiconductors are functionally integrated onto non-single-crystal platforms. (orig.)

  16. Single-crystal growth of ceria-based materials

    International Nuclear Information System (INIS)

    Ulbrich, Gregor

    2015-01-01

    In this work it could be shown that Skull-Melting is a suitable method for growing ceria single crystals. Twenty different ceria-based single crystals could be manufactured. It was possible to dope ceria single crystals with Gd, Sm, Y, Zr, Ti, Ta, and Pr in different concentrations. Also co-doping with the named metals was realized. However, there remain some problems for growing ceria-based single crystals by Skull-Melting. As ignition metal zirconium was used because no ceria-based material works well. For that reason all single crystals show small zirconium contamination. Another problem is the formation of oxygen by the heat-induced reduction of ceria during the melting process. Because of that the skull of sintered material is often destroyed by gas pressure. This problem had to be solved individually for every single crystal. The obtained single crystals were characterized using different methods. To ensure the single crystal character the y were examined by Laue diffraction. All manufactured crystals are single crystals. Also powder diffraction patterns of the milled and oxidized samples were measured. For the determination of symmetry and metric the structural parameters were analyzed by the Rietveld method. All synthesized materials crystallize in space group Fm-3m known from calcium fluoride. The cubic lattice parameter a was determined for all crystals. In the case of series with different cerium and zirconium concentrations a linear correlation between cerium content and cubic lattice parameter was detected. The elemental composition was determined by WDX. All crystals show a homogeneous elemental distribution. The oxygen content was calculated because the WDX method isn't useful for determination.

  17. Quantitative analysis with advanced compensated polarized light microscopy on wavelength dependence of linear birefringence of single crystals causing arthritis

    Science.gov (United States)

    Takanabe, Akifumi; Tanaka, Masahito; Taniguchi, Atsuo; Yamanaka, Hisashi; Asahi, Toru

    2014-07-01

    To improve our ability to identify single crystals causing arthritis, we have developed a practical measurement system of polarized light microscopy called advanced compensated polarized light microscopy (A-CPLM). The A-CPLM system is constructed by employing a conventional phase retardation plate, an optical fibre and a charge-coupled device spectrometer in a polarized light microscope. We applied the A-CPLM system to measure linear birefringence (LB) in the visible region, which is an optical anisotropic property, for tiny single crystals causing arthritis, i.e. monosodium urate monohydrate (MSUM) and calcium pyrophosphate dihydrate (CPPD). The A-CPLM system performance was evaluated by comparing the obtained experimental data using the A-CPLM system with (i) literature data for a standard sample, MgF2, and (ii) experimental data obtained using an established optical method, high-accuracy universal polarimeter, for the MSUM. The A-CPLM system was found to be applicable for measuring the LB spectra of the single crystals of MSUM and CPPD, which cause arthritis, in the visible regions. We quantitatively reveal the large difference in LB between MSUM and CPPD crystals. These results demonstrate the usefulness of the A-CPLM system for distinguishing the crystals causing arthritis.

  18. Growth, mechanical, and magnetic study of SmFeO{sub 3} single crystal grown by optical floating zone technique

    Energy Technology Data Exchange (ETDEWEB)

    Babu, P. Ramesh [Centre for Crystal Growth, VIT University, Vellore, Tamil Nadu (India); Bhaumik, Indranil [Crystal Growth Laboratory, Laser Materials Development and Devices Division, RRCAT, Indore (India); Ganesamoorthy, S. [Material Science Group, IGCAR, Kalpakkam, Tamil Nadu (India); Kalainathan, S., E-mail: kalainathan@yahoo.com [Centre for Crystal Growth, VIT University, Vellore, Tamil Nadu (India); Bhatt, R.; Karnal, A.K.; Gupta, P.K. [Crystal Growth Laboratory, Laser Materials Development and Devices Division, RRCAT, Indore (India)

    2016-08-15

    Single crystals of Samarium orthoferrite (SmFeO{sub 3}) have been grown by the optical floating zone technique. The growth parameters to yield good quality crystals are 5 mm/h for pulling and 30–40 rpm for rotation. The mechanical behavior of the grown crystal has been investigated. Rosette pattern has been observed around the indentation and the microhardness has been found to decreases non-linearly with the applied load. For load higher than 1.96 N there is a transition from palmqvist to median crack due to plastic deformation of the crystal. The hardness parameters like fracture toughness, brittleness index, and yield strength have also been calculated for palmqvist and median cracks occurring on the crystal surface. The magnetic investigations revealed that a magnetic transition in the range of 300–180 K. Above 180 K, the magnetization decreases as Sm and Fe sublattices have opposite spins. At high temperature, two anomalies are observed, one due to near spin reorientation (T{sub SR} = 480 K) and the other is AFM to paramagnetic transitions (T{sub N} = 670 K). The M–H curves exhibit a shape change with temperature due to the emergence and enlargement of multi-domain state of the SmFeO{sub 3} crystals. Bloch parameter (3.28 × 10{sup −5} K{sup −3/2}) has also been evaluated. - Highlights: • SmFeO{sub 3} single crystals have been grown by OFZ technique in air. • The microhardness has been found to decreases non-linearly with the applied load. • At 472 K, spin reorientation occurs in Fe sublattice. • The M–H curves exhibit a shape change with temperature due to the emergence and enlargement of multi-domain state. • Bloch 3/2-law holds good for SmFeO{sub 3} (B-parameter as 3.28 × 10{sup −5} K{sup −3/2}).

  19. Analysis and modification of blue sapphires from Rwanda by ion beam techniques

    International Nuclear Information System (INIS)

    Bootkul, D.; Chaiwai, C.; Tippawan, U.; Wanthanachaisaeng, B.; Intarasiri, S.

    2015-01-01

    Highlights: • Ion beam analysis is an effective method for detecting trace elements. • Ion beam treatment is able to improve optical and color appearances of the blue sapphire from Rwanda. • These alternative methods can be extended to jewelry industry for large scale application. - Abstract: Blue sapphire is categorised in a corundum (Al_2O_3) group. The gems of this group are always amazed by their beauties and thus having high value. In this study, blue sapphires from Rwanda, recently came to Thai gemstone industry, are chosen for investigations. On one hand, we have applied Particle Induced X-ray Emission (PIXE), which is a highly sensitive and precise analytical technique that can be used to identify and quantify trace elements, for chemical analysis of the sapphires. Here we have found that the major element of blue sapphires from Rwanda is Al with trace elements such as Fe, Ti, Cr, Ga and Mg as are commonly found in normal blue sapphire. On the other hand, we have applied low and medium ion implantations for color improvement of the sapphire. It seems that a high amount of energy transferring during cascade collisions have altered the gems properties. We have clearly seen that the blue color of the sapphires have been intensified after nitrogen ion bombardment. In addition, the gems were also having more transparent and luster. The UV–Vis–NIR measurement detected the modification of their absorption properties, implying of the blue color increasing. Here the mechanism of these modifications is postulated and reported. In any point of view, the bombardment by using nitrogen ion beam is a promising technique for quality improvement of the blue sapphire from Rwanda.

  20. Advanced Electroactive Single Crystal and Polymer Actuator Concepts for Passive Optics, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes large stroke and high precision piezoelectric single crystal and electroactive polymer actuator concepts?HYBrid Actuation System (HYBAS)...

  1. Single crystalline growth of a soluble organic semiconductor in a parallel aligned liquid crystal solvent using rubbing-treated polyimide films

    Science.gov (United States)

    Matsuzaki, Tomoya; Shibata, Yosei; Takeda, Risa; Ishinabe, Takahiro; Fujikake, Hideo

    2017-01-01

    For directional control of organic single crystals, we propose a crystal growth method using liquid crystal as the solvent. In this study, we examined the formation of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) single crystals using a parallel aligned liquid crystal (LC) cell and rubbing-treated polyimide films in order to clarify the effects of LC alignment on anisotropic C8-BTBT crystal growth. Based on the results, we found that the crystal growth direction of C8-BTBT single crystals was related to the direction of the aligned LC molecules because of rubbing treatment. Moreover, by optical evaluation, we found that the C8-BTBT single crystals have a aligned molecular structure.

  2. Microscopic origin of the optical processes in blue sapphire.

    Science.gov (United States)

    Bristow, Jessica K; Parker, Stephen C; Catlow, C Richard A; Woodley, Scott M; Walsh, Aron

    2013-06-11

    Al2O3 changes from transparent to a range of intense colours depending on the chemical impurities present. In blue sapphire, Fe and Ti are incorporated; however, the chemical process that gives rise to the colour has long been debated. Atomistic modelling identifies charge transfer from Ti(III) to Fe(III) as being responsible for the characteristic blue appearance.

  3. Microscopic origin of the optical processes in blue sapphire

    OpenAIRE

    Bristow, JK; Parker, SC; Catlow, CRA; Woodley, SM; Walsh, A

    2013-01-01

    Al2O3 changes from transparent to a range of intense colours depending on the chemical impurities present. In blue sapphire, Fe and Ti are incorporated; however, the chemical process that gives rise to the colour has long been debated. Atomistic modelling identifies charge transfer from Ti(III) to Fe(III) as being responsible for the characteristic blue appearance.

  4. Investigations on the optical, thermal and surface modifications of electron irradiated L-threonine single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Ramesh Kumar, G.; Gokul Raj, S. [Department of Physics, Presidency College, Chepauk, Chennai 600005 (India); Bogle, K.A.; Dhole, S.D.; Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India); Mohan, R. [Department of Physics, Presidency College, Chepauk, Chennai 600005 (India)], E-mail: professormohan@yahoo.co.in

    2008-06-15

    L-Threonine single crystals have been irradiated by 6 MeV electrons. Irradiated crystals at various electron fluences were subjected to various techniques such as UV-vis-NIR, atomic force microscopy (AFM) and thermomechanical analyses. Thermal strength of the irradiated crystals has also been studied through differential scanning calorimetry (DSC) measurements. The results have been discussed in detail.

  5. Growth and physicochemical properties of organometallic (DL)-trithioureatartrato-O1,O2,O3-cadmium(II) single crystals

    Science.gov (United States)

    Sathyamoorthy, K.; Vinothkumar, P.; Irshad Ahamed, J.; Murali Manohar, P.; Priya, M.; Liu, Jinghe

    2018-04-01

    Single crystals of organometallic (DL)-trithioureatartrato-O1,O2,O3-cadmium(II) (TUDLC) have been grown from methanol solution by using the slow evaporation of solvent growth technique. The lattice structure and crystalline perfection have been determined by carrying out single crystal X-ray diffraction and high resolution X-ray diffraction measurements. The grown crystal was characterized thermally and mechanically by carrying out thermo-gravimetric and micro hardness measurements. The linear and nonlinear optical characterizations were made by carrying out optical transmittance, surface laser damage threshold, particle size-dependent second harmonic generation (SHG) efficiency and photo conductivity measurements. The grown crystal was electrically characterized by carrying out frequency-dependent dielectric measurements. Chemical etching study was also carried out and the dislocation density was estimated. Results obtained in the present study indicate that the grown TUDLC crystal is optically transparent with lower cut-off wavelength 304 nm, mechanically soft, thermally stable up to 101 °C and NLO active with SHG efficiency 2.13 (in KDP unit). The grown crystal is found to have considerably large size, good crystalline perfection, large specific heat capacity, higher surface laser damage threshold and negative photoconductivity.

  6. Electronic structure and optical properties of LiGa0.5In0.5Se2 single crystal, a nonlinear optical mid-IR material

    Science.gov (United States)

    Lavrentyev, A. A.; Gabrelian, B. V.; Vu, Tuan V.; Isaenko, L. I.; Yelisseyev, A. P.; Khyzhun, O. Y.

    2018-06-01

    Measurements of X-ray photoelectron core-level and valence-band spectra for pristine and irradiated with Ar+ ions surfaces of LiGa0.5In0.5Se2 single crystal, novel nonlinear optical mid-IR selenide grown by a modified vertical Bridgman-Stockbarger technique, are reported. Electronic structure of LiGa0.5In0.5Se2 is elucidated from theoretical and experimental points of view. Notably, total and partial densities of states (DOSs) of the LiGa0.5In0.5Se2 compound are calculated based on density functional theory (DFT) using the augmented plane wave + local orbitals (APW + lo) method. In accordance with the DFT calculations, the principal contributors to the valence band are the Se 4p states, making the main input at the top and in the upper part of the band, while its bottom is dominated by contributions of the valence s states associated with Ga and In atoms. The theoretical total DOS curve peculiarities are found to be in excellent agreement with the shape of the X-ray photoelectron valence-band spectrum of the LiGa0.5In0.5Se2 single crystal. The bottom of the conduction band of LiGa0.5In0.5Se2 is formed mainly by contributions of the unoccupied Ga 4s and In 5s states in almost equal proportion, with somewhat smaller contributions of the unoccupied Se 4p states as well. Our calculations indicate that the LiGa0.5In0.5Se2 compound is a direct gap semiconductor. The principal optical constants of LiGa0.5In0.5Se2 are calculated in the present work.

  7. Cavity electromagnetically induced transparency and all-optical switching using ion Coulomb crystals

    DEFF Research Database (Denmark)

    Albert, Magnus; Dantan, Aurelien Romain; Drewsen, Michael

    2011-01-01

    The control of one light field by another, ultimately at the single photon level1, 2, 3, 4, 5, 6, 7, is a challenging task that has numerous interesting applications within nonlinear optics4, 5 and quantum information science6, 7, 8. This type of control can only be achieved through highly...... nonlinear interactions, such as those based on electromagnetic induced transparency (EIT)2, 3, 4, 5, 6, 9, 10, 11, 12. Here, we demonstrate for the first time EIT as well as all-optical EIT-based light switching using ion Coulomb crystals situated in an optical cavity. Changes from essentially full...... milestones for future realizations of quantum information processing devices, such as high-efficiency quantum memories8, 13, 14, single-photon transistors15, 16 and single-photon gates4, 6, 9....

  8. Effect of the electronic structure of the etched CdTe single crystals on the exciton radiation processes

    International Nuclear Information System (INIS)

    Tkachuk, P.M.; Tkachuk, V.Yi.; Mel'nichuk, S.V.; Kurik, M.V.

    2005-01-01

    Under optical excitation the structure of the radiation beyond fundamental absorption of the orientated CdTe single crystals caused by LO-phonon scattering processes of the electron-hole states is observed. Crystals have been doped with impurity of Cl as a result of the surface preparing by etching in Br-methanol. Electronic structure of the single crystals surface layer is identified on the basis of two-phonon radiation absorption investigation. Taking into account the modes selection rules the one and two phonon scattering mechanisms for two crystals surface orientations are determined

  9. Development of n- and p-type Doped Perovskite Single Crystals Using Solid-State Single Crystal Growth (SSCG) Technique

    Science.gov (United States)

    2017-10-09

    for AGG should be minimal. For this purpose, the seeds for AGG may also be provided externally. This process is called the solid-state single...bonding process . Figure 31 shows (a) the growth of one large single crystal from one small single crystal seed as well as (b) the growth of one...one bi-crystal seed : One large bi-crystal can be grown from one small bi-crystal by SSCG process . Fig. 32. Diffusion bonding process for

  10. Crystal-free Formation of Non-Oxide Optical Fiber

    Science.gov (United States)

    Nabors, Sammy A.

    2015-01-01

    Researchers at NASA Marshall Space Flight Center have devised a method for the creation of crystal-free nonoxide optical fiber preforms. Non-oxide fiber optics are extensively used in infrared transmitting applications such as communication systems, chemical sensors, and laser fiber guides for cutting, welding and medical surgery. However, some of these glasses are very susceptible to crystallization. Even small crystals can lead to light scatter and a high attenuation coefficient, limiting their usefulness. NASA has developed a new method of non-oxide fiber formation that uses axial magnetic fields to suppress crystallization. The resulting non-oxide fibers are crystal free and have lower signal attenuation rates than silica based optical fibers.

  11. Optical spectroscopy of Pr3+ in M+Bi(XO4)2, M+ = Li or Na and X = W or Mo, locally disordered single crystals

    International Nuclear Information System (INIS)

    Mendez-Blas, A; Rico, M; Volkov, V; Cascales, C; Zaldo, C; Coya, C; Kling, A; Alves, L C

    2004-01-01

    NaBi(WO 4 ) 2 (NBW), NaBi(MoO 4 ) 2 (NBMo) and LiBi(MoO 4 ) 2 (LBMo) single crystals grown by the Czochralski technique have been doped up to a praseodymium concentration of Pr ∼1x10 20 cm -3 in the crystal. 10 K polarized optical absorption and photoluminescence measurements have been used to determine the energy position of 32, 39 and 36 Pr 3+ Stark levels in NBW, NBMo and LBMo crystals, respectively. These energy levels were labelled with the appropriate irreducible representations corresponding to a C 2 local symmetry of an average optical centre. Single-electron Hamiltonians including free-ion and crystal field interactions have been used in the fitting of experimental energy levels and in the simulation of the full sequence of the 4f 2 Pr 3+ configuration. 300 K absorption spectra of different 2S+1 L J Pr 3+ multiplets were determined and used in the context of the Judd-Ofelt theory and for the calculation of the 1 D 2 -related emission cross sections of this average Pr 3+ centre. Non-radiative electron relaxation from the 3 P 0 level feeds the 1 D 2 multiplet. This latter level efficiently decays radiatively to the ground 3 H 4 multiplet but still there is a significant rate of radiative decay to the 1 D → 3 F 3 praseodymium laser channel. For Pr ≥ 2x10 19 cm -3 , non-radiative electric dipole-dipole Pr pair energy transfer limits the radiative yield

  12. Single Crystals of Organolead Halide Perovskites: Growth, Characterization, and Applications

    KAUST Repository

    Peng, Wei

    2017-04-01

    With the soaring advancement of organolead halide perovskite solar cells rising from a power conversion efficiency of merely 3% to more than 22% shortly in five years, researchers’ interests on this big material family have been greatly spurred. So far, both in-depth studies on the fundamental properties of organolead halide perovskites and their extended applications such as photodetectors, light emitting diodes, and lasing have been intensively reported. The great successes have been ascribed to various superior properties of organolead halide hybrid perovskites such as long carrier lifetimes, high carrier mobility, and solution-processable high quality thin films, as will be discussed in Chapter 1. Notably, most of these studies have been limited to their polycrystalline thin films. Single crystals, as a counter form of polycrystals, have no grain boundaries and higher crystallinity, and thus less defects. These characteristics gift single crystals with superior optical, electrical, and mechanical properties, which will be discussed in Chapter 2. For example, organolead halide perovskite single crystals have been reported with much longer carrier lifetimes and higher carrier mobilities, which are especially intriguing for optoelectronic applications. Besides their superior optoelectronic properties, organolead halide perovskites have shown large composition versatility, especially their organic components, which can be controlled to effectively adjust their crystal structures and further fundamental properties. Single crystals are an ideal platform for such composition-structure-property study since a uniform structure with homogeneous compositions and without distraction from grain boundaries as well as excess defects can provide unambiguously information of material properties. As a major part of work of this dissertation, explorative work on the composition-structure-property study of organic-cation-alloyed organolead halide perovskites using their single

  13. Growth of CuSO4 · 5H2O single crystals and study of some of their properties

    Science.gov (United States)

    Manomenova, V. L.; Stepnova, M. N.; Grebenev, V. V.; Rudneva, E. B.; Voloshin, A. E.

    2013-05-01

    Large single crystals of copper sulfate pentahydrate CuSO4 · 5H2O of optical quality have been grown; they can be applied as broadband UV optical filters. Their transmission spectra are measured. The crystal thermal stability is investigated and the onset temperature of dehydration is determined to be 46°C.

  14. Dispersion properties and low infrared optical losses in epitaxial AlN on sapphire substrate in the visible and infrared range

    International Nuclear Information System (INIS)

    Soltani, A.; Stolz, A.; Gerbedoen, J.-C.; Rousseau, M.; Bourzgui, N.; De Jaeger, J.-C.; Charrier, J.; Mattalah, M.; Barkad, H. A.; Mortet, V.; BenMoussa, A.

    2014-01-01

    Optical waveguiding properties of a thick wurtzite aluminum nitride highly [002]-textured hetero-epitaxial film on (001) basal plane of sapphire substrate are studied. The physical properties of the film are determined by X-ray diffraction, atomic force microscopy, microRaman, and photocurrent spectroscopy. The refractive index and the thermo-optic coefficients are determined by m-lines spectroscopy using the classical prism coupling technique. The optical losses of this planar waveguide are also measured in the spectral range of 450–1553 nm. The lower value of optical losses is equal to 0.7 dB/cm at 1553 nm. The optical losses due to the surface scattering are simulated showing that the contribution is the most significant at near infrared wavelength range, whereas the optical losses are due to volume scattering and material absorption in the visible range. The good physical properties and the low optical losses obtained from this planar waveguide are encouraging to achieve a wide bandgap optical guiding platform from these aluminum nitride thin films

  15. Dispersion properties and low infrared optical losses in epitaxial AlN on sapphire substrate in the visible and infrared range

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, A., E-mail: ali.soltani@iemn.univ-lille1.fr; Stolz, A.; Gerbedoen, J.-C.; Rousseau, M.; Bourzgui, N.; De Jaeger, J.-C. [Institut d' Électronique, Microélectronique et Nanotechnologie, UMR-CNRS 8520, PRES Université Lille Nord de France, Cité Scientifique, Avenue Poincaré, CS 60069, 59652 Villeneuve d' Ascq Cedex (France); Charrier, J. [Fonctions Optiques pour les Technologies de l' informatiON, UMR-CNRS 6082, ENSSAT 6, rue de Kerampont, CS 80518, 22305 Lannion Cedex (France); Mattalah, M. [Laboratoire de Microélectronique, Université Djilali Liabes, 22000 Sidi Bel Abbes (Algeria); Barkad, H. A. [Institut Universitaire Technologique Industriel, Université de Djibouti, Avenue Georges Clémenceau, BP 1904 Djibouti (Djibouti); Mortet, V. [Institute of Physics of Academy of Sciences of Czech Republic, Fyzikální ústav AV CR, v.v.i., Na Slovance 1999/2 (Czech Republic); BenMoussa, A. [Solar Terrestrial Center of Excellence, Royal Observatory of Belgium, Circular 3, B-1180 Brussels (Belgium)

    2014-04-28

    Optical waveguiding properties of a thick wurtzite aluminum nitride highly [002]-textured hetero-epitaxial film on (001) basal plane of sapphire substrate are studied. The physical properties of the film are determined by X-ray diffraction, atomic force microscopy, microRaman, and photocurrent spectroscopy. The refractive index and the thermo-optic coefficients are determined by m-lines spectroscopy using the classical prism coupling technique. The optical losses of this planar waveguide are also measured in the spectral range of 450–1553 nm. The lower value of optical losses is equal to 0.7 dB/cm at 1553 nm. The optical losses due to the surface scattering are simulated showing that the contribution is the most significant at near infrared wavelength range, whereas the optical losses are due to volume scattering and material absorption in the visible range. The good physical properties and the low optical losses obtained from this planar waveguide are encouraging to achieve a wide bandgap optical guiding platform from these aluminum nitride thin films.

  16. Creation of oxygen-enriched layers at the surface of GaAs single crystal

    International Nuclear Information System (INIS)

    Kulik, M.; Maczka, D.; Kobzev, A.P.

    1999-01-01

    The optical properties and the element depth profiles at the (100) plane high resistant and noncomposite GaAs single crystals implanted with In ions were investigated. The results have been compared with those obtained for virgin samples. The optic properties for all of the samples (implanted and not implanted, annealed and not annealed) have been measured using the ellipsometric method. The element depth profiles for the same samples have been obtained by the RBS and NRA techniques. It has been shown that the post-implantation annealing at a temperature more than 600 deg C leads to a ten time increase in contents of oxygen atoms in the implanted layer with respect to the not annealed sample. The thickness of the transparence layer at the surface of GaAs single crystal increases also after implantation with In ions and subsequent annealing

  17. Dielectric, optical and mechanical studies of phenolic polyene OH1 organic electrooptic crystal

    Science.gov (United States)

    Bharath, D.; Kalainathan, S.

    2014-11-01

    2-{3-[2-(4-Hydroxyphenyl) vinyl]-5, 5-dimethylcyclo-hex-2-en-1-ylidene}malononitrile (OH1) phenolic locked polyene organic material has been synthesized by the Knoevenagel condensation method. OH1 single crystals were grown in methanol by a slow evaporation method. In order to avoid the multinucleation and reduce the metastable zone width, phosphoric acid is added in different concentrations. The linear optical property of OH1 crystal has been studied using UV-vis-NIR spectroscopy in the wavelength range 190-1100 nm and optical constants are calculated theoretically. The magnitude of nonlinear refractive index (10-12 m2/W), nonlinear absorption (10-6 m/W) and third order nonlinear susceptibility (10-6 esu) has been studied using a Z-scan technique. Dielectric property of OH1 crystal has been studied in frequency range 50 Hz-5 MHz. Photoluminescence spectrum was recorded using a xenon lamp in the range of 450-700 nm. Laser optical damage threshold of OH1 crystal was obtained (0.62 GW/cm2) using a pulsed Nd-YAG laser (1064 nm) of repetition rate 10 ns.

  18. Phonon assisted electronic transition in telluric acid ammonium phosphate single crystals

    Science.gov (United States)

    El-Muraikhi, M.; Kassem, M. E.; Al-Houty, L.

    The effect of gamma-irradiation on the absorption optical spectra of telluric acid ammonium phosphate single crystals (TAAP) has been studied, in the wave length of 200-600 nm, for samples irradiated by various doses up to 10 Mrad. The results show that the electron phonon coupling constant increases with the irradiation dose.

  19. Thermal healing of the sub-surface damage layer in sapphire

    International Nuclear Information System (INIS)

    Pinkas, Malki; Lotem, Haim; Golan, Yuval; Einav, Yeheskel; Golan, Roxana; Chakotay, Elad; Haim, Avivit; Sinai, Ela; Vaknin, Moshe; Hershkovitz, Yasmin; Horowitz, Atara

    2010-01-01

    The sub-surface damage layer formed by mechanical polishing of sapphire is known to reduce the mechanical strength of the processed sapphire and to degrade the performance of sapphire based components. Thermal annealing is one of the methods to eliminate the sub-surface damage layer. This study focuses on the mechanism of thermal healing by studying its effect on surface topography of a- and c-plane surfaces, on the residual stresses in surface layers and on the thickness of the sub-surface damage layer. An atomically flat surface was developed on thermally annealed c-plane surfaces while a faceted roof-top topography was formed on a-plane surfaces. The annealing resulted in an improved crystallographic perfection close to the sample surface as was indicated by a noticeable decrease in X-ray rocking curve peak width. Etching experiments and surface roughness measurements using white light interferometry with sub-nanometer resolution on specimens annealed to different extents indicate that the sub-surface damage layer of the optically polished sapphire is less than 3 μm thick and it is totally healed after thermal treatment at 1450 deg. C for 72 h.

  20. Optical absorption in SrC4H4O6·3H2O crystals

    International Nuclear Information System (INIS)

    Arora, S.K.; Patel, Vipul; Kothari, Anjana; Chudasama, Bhupendra

    2004-01-01

    Study of optical absorption in the gel-grown strontium tartrate trihydrate (STT) single crystals measured in UV-vis range at room temperature reveals transitions involving absorption and emission of phonons. Based on the theory of interband optical absorptions, the electronic transition near the fundamental absorption edge is analysed. Some feeble disorder in the crystal is conceived to be present. The analysis carried out hereunder leads to estimation of energy of the lattice phonons involved

  1. Growth and characterizaion of urea p-nitrophenol crystal: an organic nonlinear optical material for optoelectronic device application

    Science.gov (United States)

    Suresh, A.; Manikandan, N.; Jauhar, RO. MU.; Murugakoothan, P.; Vinitha, G.

    2018-06-01

    Urea p-nitrophenol, an organic nonlinear optical crystal was synthesized and grown adopting slow evaporation and seed rotation method. Single crystal X-ray diffraction study confirmed the formation of the desired crystal. High resolution X-ray diffraction study showed the defect nature of the crystal. The presence of functional groups in the material was confirmed by FTIR analysis. UV-Vis-NIR study indicates that the grown crystal has a wider transparency region with the lower cutoff wavelength at 423 nm. The grown crystal is thermally stable up to 120 °C as assessed by TG-DTA analysis. The optical homogeneity of the grown crystal was confirmed by birefringence study. The 1064 nm Nd-YAG laser was used to obtain laser induced surface damage threshold which was found to be 0.38, 0.25 and 0.33 GW/cm2 for (0 1 0), (1 1 - 1) and (0 1 1) planes, respectively. The dielectric study was performed to find the charge distribution inside the crystal. The hardness property of the titular material has been found using Vicker's microhardness study. The optical nonlinearity obtained from third order nonlinear optical measurements carried out using Z-scan technique showed that these samples could be exploited for optical limiting studies.

  2. Analysis and modification of blue sapphires from Rwanda by ion beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Bootkul, D., E-mail: mo_duangkhae@hotmail.com [Department of General Science - Gems & Jewelry, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Chaiwai, C.; Tippawan, U. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanthanachaisaeng, B. [Gems Enhancement Research Unit, Faculty of Gems, Burapha University, Chanthaburi Campus, Chanthaburi 22170 (Thailand); Intarasiri, S., E-mail: saweat@gmail.com [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2015-12-15

    Highlights: • Ion beam analysis is an effective method for detecting trace elements. • Ion beam treatment is able to improve optical and color appearances of the blue sapphire from Rwanda. • These alternative methods can be extended to jewelry industry for large scale application. - Abstract: Blue sapphire is categorised in a corundum (Al{sub 2}O{sub 3}) group. The gems of this group are always amazed by their beauties and thus having high value. In this study, blue sapphires from Rwanda, recently came to Thai gemstone industry, are chosen for investigations. On one hand, we have applied Particle Induced X-ray Emission (PIXE), which is a highly sensitive and precise analytical technique that can be used to identify and quantify trace elements, for chemical analysis of the sapphires. Here we have found that the major element of blue sapphires from Rwanda is Al with trace elements such as Fe, Ti, Cr, Ga and Mg as are commonly found in normal blue sapphire. On the other hand, we have applied low and medium ion implantations for color improvement of the sapphire. It seems that a high amount of energy transferring during cascade collisions have altered the gems properties. We have clearly seen that the blue color of the sapphires have been intensified after nitrogen ion bombardment. In addition, the gems were also having more transparent and luster. The UV–Vis–NIR measurement detected the modification of their absorption properties, implying of the blue color increasing. Here the mechanism of these modifications is postulated and reported. In any point of view, the bombardment by using nitrogen ion beam is a promising technique for quality improvement of the blue sapphire from Rwanda.

  3. Single crystal growth and nonlinear optical properties of Nd3+ doped STGS crystal for self-frequency-doubling application

    Science.gov (United States)

    Chen, Feifei; Wang, Lijuan; Wang, Xinle; Cheng, Xiufeng; Yu, Fapeng; Wang, Zhengping; Zhao, Xian

    2017-11-01

    The self-frequency-doubling crystal is an important kind of multi-functional crystal materials. In this work, Nd3+ doped Sr3TaGa3Si2O14 (Nd:STGS) single crystals were successfully grown by using Czochralski pulling method, in addition, the nonlinear and laser-frequency-doubling properties of Nd:STGS crystals were studied. The continuous-wave laser at 1064 nm was demonstrated along different physical axes, where the maximum output power was obtained to be 295 mW for the Z-cut samples, much higher than the Y-cut (242 mW) and X-cut (217 mW) samples. Based on the measured refractive indexes, the phase matching directions were discussed and determined for type I (42.5°, 30°) and type II (69.5°, 0°) crystal cuts. As expected, self-frequency-doubling green laser at 529 nm was achieved with output powers being around 16 mW and 12 mW for type I and type II configurations, respectively.

  4. Characteristics of surface acoustic waves in (11\\bar 2 0)ZnO film/ R-sapphire substrate structures

    Science.gov (United States)

    Wang, Yan; Zhang, ShuYi; Xu, Jing; Xie, YingCai; Lan, XiaoDong

    2018-02-01

    (11\\bar 2 0)ZnO film/ R-sapphire substrate structure is promising for high frequency acoustic wave devices. The propagation characteristics of SAWs, including the Rayleigh waves along [0001] direction and Love waves along [1ī00] direction, are investigated by using 3 dimensional finite element method (3D-FEM). The phase velocity ( v p), electromechanical coupling coefficient ( k 2), temperature coefficient of frequency ( TCF) and reflection coefficient ( r) of Rayleigh wave and Love wave devices are theoretically analyzed. Furthermore, the influences of ZnO films with different crystal orientation on SAW properties are also investigated. The results show that the 1st Rayleigh wave has an exceedingly large k 2 of 4.95% in (90°, 90°, 0°) (11\\bar 2 0)ZnO film/ R-sapphire substrate associated with a phase velocity of 5300 m/s; and the 0th Love wave in (0°, 90°, 0°) (11\\bar 2 0)ZnO film/ R-sapphire substrate has a maximum k 2 of 3.86% associated with a phase velocity of 3400 m/s. And (11\\bar 2 0)ZnO film/ R-sapphire substrate structures can be used to design temperature-compensated and wide-band SAW devices. All of the results indicate that the performances of SAW devices can be optimized by suitably selecting ZnO films with different thickness and crystal orientations deposited on R-sapphire substrates.

  5. Green-diode-pumped femtosecond Ti:Sapphire laser with up to 450 mW average power.

    Science.gov (United States)

    Gürel, K; Wittwer, V J; Hoffmann, M; Saraceno, C J; Hakobyan, S; Resan, B; Rohrbacher, A; Weingarten, K; Schilt, S; Südmeyer, T

    2015-11-16

    We investigate power-scaling of green-diode-pumped Ti:Sapphire lasers in continuous-wave (CW) and mode-locked operation. In a first configuration with a total pump power of up to 2 W incident onto the crystal, we achieved a CW power of up to 440 mW and self-starting mode-locking with up to 200 mW average power in 68-fs pulses using semiconductor saturable absorber mirror (SESAM) as saturable absorber. In a second configuration with up to 3 W of pump power incident onto the crystal, we achieved up to 650 mW in CW operation and up to 450 mW in 58-fs pulses using Kerr-lens mode-locking (KLM). The shortest pulse duration was 39 fs, which was achieved at 350 mW average power using KLM. The mode-locked laser generates a pulse train at repetition rates around 400 MHz. No complex cooling system is required: neither the SESAM nor the Ti:Sapphire crystal is actively cooled, only air cooling is applied to the pump diodes using a small fan. Because of mass production for laser displays, we expect that prices for green laser diodes will become very favorable in the near future, opening the door for low-cost Ti:Sapphire lasers. This will be highly attractive for potential mass applications such as biomedical imaging and sensing.

  6. Eliminating Crystals in Non-Oxide Optical Fiber Preforms and Optical Fibers

    Science.gov (United States)

    Tucker, Dennis S.; LaPointe, Michael R.

    2012-01-01

    Non ]oxide fiber optics such as heavy metal fluoride and chalcogenide glasses are extensively used in infrared transmitting applications such as communication systems, chemical sensors, and laser fiber guides for cutting, welding and medical surgery. The addition of rare earths such as erbium, enable these materials to be used as fiber laser and amplifiers. Some of these glasses however are very susceptible to crystallization. Even small crystals can lead to light scatter and a high attenuation coefficient, limiting their usefulness. Previously two research teams found that microgravity suppressed crystallization in heavy metal fluoride glasses. Looking for a less expensive method to suppress crystallization, ground based research was performed utilizing an axial magnetic field. The experiments revealed identical results to those obtained via microgravity processing. This research then led to a patented process for eliminating crystals in optical fiber preforms and the resulting optical fibers. In this paper, the microgravity results will be reviewed as well as patents and papers relating to the use of magnetic fields in various material and glass processing applications. Finally our patent to eliminate crystals in non ]oxide glasses utilizing a magnetic field will be detailed.

  7. Photonics of 2D gold nanolayers on sapphire surface

    Energy Technology Data Exchange (ETDEWEB)

    Muslimov, A. E., E-mail: amuslimov@mail.ru; Butashin, A. V.; Nabatov, B. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Research Center “Crystallography and Photonics” (Russian Federation); Konovko, A. A.; Belov, I. V.; Gizetdinov, R. M.; Andreev, A. V. [Moscow State University (Russian Federation); Kanevsky, V. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Research Center “Crystallography and Photonics” (Russian Federation)

    2017-03-15

    Gold layers with thicknesses of up to several nanometers, including ordered and disordered 2D nanostructures of gold particles, have been formed on sapphire substrates; their morphology is described; and optical investigations are carried out. The possibility of increasing the accuracy of predicting the optical properties of gold layers and 2D nanostructures using quantum-mechanical models based on functional density theory calculation techniques is considered. The application potential of the obtained materials in photonics is estimated.

  8. Single Molecules as Optical Probes for Structure and Dynamics

    Science.gov (United States)

    Orrit, Michel

    Single molecules and single nanoparticles are convenient links between the nanoscale world and the laboratory. We discuss the limits for their optical detection by three different methods: fluorescence, direct absorption, and photothermal detection. We briefly review some recent illustrations of qualitatively new information gathered from single-molecule signals: intermittency of the fluorescence intensity, acoustic vibrations of nanoparticles (1-100 GHz) or of extended defects in molecular crystals (0.1-1 MHz), and dynamical heterogeneity in glass-forming molecular liquids. We conclude with an outlook of future uses of single-molecule methods in physical chemistry, soft matter, and material science.

  9. Formation of oriented nitrides by N+ ion implantation in iron single crystals

    International Nuclear Information System (INIS)

    Costa, A.R.G.; Silva, R.C. da; Ferreira, L.P.; Carvalho, M.D.; Silva, C.; Franco, N.; Godinho, M.

    2014-01-01

    Iron single crystals were implanted with nitrogen at room temperature, with a fluence of 5×10 17 cm −2 and 50 keV energy, to produce iron nitride phases and characterize the influence of the crystal orientation. The stability and evolution of the nitride phases and diffusion of implanted nitrogen were studied as a function of successive annealing treatments at 250 °C in vacuum. The composition, structure and magnetic properties were characterized using RBS/channeling, X-Ray Diffraction, Magnetic Force Microscopy, Magneto-optical Kerr Effect and Conversion Electron Mössbauer Spectroscopy. In the as-implanted state the formation of Fe 2 N phase was clearly identified in all single crystals. This phase is not stable at 250 °C and annealing at this temperature promotes the formation of ε-Fe 3 N, or γ′-Fe 4 N, depending on the orientation of the substrate. - Highlights: • Oriented magnetic iron nitrides were obtained by nitrogen implantation into iron single crystals. • The stable magnetic nitride phase at 250 °C depends on the orientation of the host single crystal, being γ'-Fe 4 N or ε-Fe 3 N. • The easy magnetization axis was found to lay in the (100) plane for cubic γ'-Fe 4 N and out of (100) plane for hexagonal ε-Fe 3 N

  10. Structure of single-chain single crystals of isotactic polystyrene and their radiation resistance

    International Nuclear Information System (INIS)

    Bu Haishan; Cao Jie; Xu Shengyong; Zhang Ze

    1997-01-01

    The structure of the single-chain single crystals of isotactic polystyrene (i-PS) was investigated by electron diffraction (ED) and high resolution electron microscopy (HREM). The nano-scale single-chain single crystals were found to be very stable to electron irradiation. According to the unit cell of i-PS crystals, the reflection rings in ED pattern and the lattice fringes in HREM images could be indexed, but the lower-index diffractions were not found. It is proposed that the single-chain single crystals are very small, thus secondary electrons may be allowed to escape and radiation damage is highly reduced, and that there are less lower-index lattice planes in the single-chain single crystals to provide sufficient diffraction intensity for recording. HREM images can be achieved at room temperature in the case of single-chain single crystals because of its stability to electron irradiation, therefore, this might be a novel experimental approach to the study of crystal structure of macromolecules

  11. Optical and magnetic spectroscopy of rare-earth-doped yttrium aluminium borate (YAl sub 3 (BO sub 3) sub 4) single crystals

    CERN Document Server

    Watterich, A; Borowiec, M T; Zayarnyuk, T; Szymczak, H; Beregi, E; Kovács, L G

    2003-01-01

    For Ce sup 3 sup + , Er sup 3 sup + and Yb sup 3 sup + ions, electron paramagnetic resonance (EPR) spectra typical for S' = 1/2 ions are measured for YAl sub 3 (BO sub 3) sub 4 (YAB) single crystal. The spectra show axial symmetry indicating that all three dopants replace Y sup 3 sup + at the given dopant concentration. Corresponding g-tilde - and hyperfine A-tilde -tensors are determined. The EPR linewidth of Ce broadens with increasing temperature due to an Orbach relaxation process. Fitting the curve with an exponential, the energy difference is found to be equal to 270 +- 16 cm sup - sup 1. The optical absorption and excitation spectra of Ce in YAB single crystal measured at 300 K are similar to those found for polycrystalline materials. High-resolution polarized emission from the lowest excited to the sup 2 F sub 5 sub / sub 2 ground state, measured at 4.2 K, indicates a splitting of the ground state into three levels. The second level is located 277 +- 18 cm sup - sup 1 above the first one, in excellent...

  12. Introducing single-crystal scattering and optical potentials into MCNPX: Predicting neutron emission from a convoluted moderator

    Energy Technology Data Exchange (ETDEWEB)

    Gallmeier, F.X., E-mail: gallmeierfz@ornl.gov [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Iverson, E.B.; Lu, W. [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Baxter, D.V. [Center for the Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408 (United States); Muhrer, G.; Ansell, S. [European Spallation Source, ESS AB, Lund (Sweden)

    2016-04-01

    Neutron transport simulation codes are indispensable tools for the design and construction of modern neutron scattering facilities and instrumentation. Recently, it has become increasingly clear that some neutron instrumentation has started to exploit physics that is not well-modeled by the existing codes. In particular, the transport of neutrons through single crystals and across interfaces in MCNP(X), Geant4, and other codes ignores scattering from oriented crystals and refractive effects, and yet these are essential phenomena for the performance of monochromators and ultra-cold neutron transport respectively (to mention but two examples). In light of these developments, we have extended the MCNPX code to include a single-crystal neutron scattering model and neutron reflection/refraction physics. We have also generated silicon scattering kernels for single crystals of definable orientation. As a first test of these new tools, we have chosen to model the recently developed convoluted moderator concept, in which a moderating material is interleaved with layers of perfect crystals to provide an exit path for neutrons moderated to energies below the crystal's Bragg cut–off from locations deep within the moderator. Studies of simple cylindrical convoluted moderator systems of 100 mm diameter and composed of polyethylene and single crystal silicon were performed with the upgraded MCNPX code and reproduced the magnitude of effects seen in experiments compared to homogeneous moderator systems. Applying different material properties for refraction and reflection, and by replacing the silicon in the models with voids, we show that the emission enhancements seen in recent experiments are primarily caused by the transparency of the silicon and void layers. Finally we simulated the convoluted moderator experiments described by Iverson et al. and found satisfactory agreement between the measurements and the simulations performed with the tools we have developed.

  13. The sublimation kinetics of GeSe single crystals

    Science.gov (United States)

    Irene, E. A.; Wiedemeier, H.

    1975-01-01

    The sublimation kinetics of (001) oriented GeSe single crystal platelets was studied by high-temperature mass spectroscopy, quantitative vacuum microbalance techniques, and hot stage optical microscopy. For a mean experimental temperature of 563 K, the activation enthalpy and entropy are found to equal 32.3 kcal/mole and 19.1 eu, respectively. The vaporization coefficient is less than unity for the range of test temperatures, and decreases with increasing temperature. The combined experimental data are correlated by means of a multistep surface adsorption mechanism.

  14. Directed self-assembly of liquid crystalline blue-phases into ideal single-crystals

    Science.gov (United States)

    Martínez-González, Jose A.; Li, Xiao; Sadati, Monirosadat; Zhou, Ye; Zhang, Rui; Nealey, Paul F.; de Pablo, Juan J.

    2017-06-01

    Chiral nematic liquid crystals are known to form blue phases--liquid states of matter that exhibit ordered cubic arrangements of topological defects. Blue-phase specimens, however, are generally polycrystalline, consisting of randomly oriented domains that limit their performance in applications. A strategy that relies on nano-patterned substrates is presented here for preparation of stable, macroscopic single-crystal blue-phase materials. Different template designs are conceived to exert control over different planes of the blue-phase lattice orientation with respect to the underlying substrate. Experiments are then used to demonstrate that it is indeed possible to create stable single-crystal blue-phase domains with the desired orientation over large regions. These results provide a potential avenue to fully exploit the electro-optical properties of blue phases, which have been hindered by the existence of grain boundaries.

  15. Progress in linear optics, non-linear optics and surface alignment of liquid crystals

    Science.gov (United States)

    Ong, H. L.; Meyer, R. B.; Hurd, A. J.; Karn, A. J.; Arakelian, S. M.; Shen, Y. R.; Sanda, P. N.; Dove, D. B.; Jansen, S. A.; Hoffmann, R.

    We first discuss the progress in linear optics, in particular, the formulation and application of geometrical-optics approximation and its generalization. We then discuss the progress in non-linear optics, in particular, the enhancement of a first-order Freedericksz transition and intrinsic optical bistability in homeotropic and parallel oriented nematic liquid crystal cells. Finally, we discuss the liquid crystal alignment and surface effects on field-induced Freedericksz transition.

  16. Refractive indices of CaF2 single crystals under elastic shock loading

    Science.gov (United States)

    Li, Y.; Zhou, X. M.; Liu, C. L.; Luo, S. N.

    2017-07-01

    Refractive indices and Hugoniots of CaF2 single crystals are investigated by laser displacement interferometry under shock loading below 5 GPa. Birefringence is observed for the [110] loading. We obtain the Hugoniot equation of states for [100], [110] and [111], and refractive indices for these orientations with consideration of their polarization. The measured refractive indices are in reasonable agreement with predictions based on the piezo-optic theory, and are used to refine the elasto-optic coefficients.

  17. X-ray dosimetry of TlGaSe2 single crystals

    International Nuclear Information System (INIS)

    Kerimova, E.M.; Mustafaeva, S.N.; Mamedbeili, S.D.; Jabarov, J.N.; Iskenderova, P.M.; Kazimov, S.B.

    2002-01-01

    TlGaSe 2 compound belongs to group of layered semiconductors of A 3 B 3 C 2 6 -type. Photoelectric and optical properties of TlGaSe 2 single crystals were investigated in detail. Influence of gamma-, electron and neutron radiation on photoelectric properties of TlGaSe 2 single crystals is investigated too. The present work deals with experimental results relative to X-ray dosimetric characteristics of TlGaSe 2 crystals at 300 K. X-ray conductivity and X-ray dosimetric characteristic measurements are carried out in low load resistance regime. The source of X-ray radiation is the installation of X-ray diffraction analysis (URS-55a) with the BCV-2(Cu). Intensity of X-ray radiation (E) is regulated by measurement with current variation in tube at each given value of X-ray radiation dose E (R/min) are measured by crystal dosimeter DRGZ-02. X-ray conductivity coefficients K σ characterising X-ray sensitivity of investigated crystals are determined as the relative change of conductivity under X-ray radiation a per dose. There have been determined values of characteristic coefficients of TlGaSe 2 single crystal X-ray conductivity at different values of accelerating voltage (V a ) on the tube and corresponding doses of X-ray radiation. Analysis of obtained data showed that X-ray conductivity coefficients K σ in studied crystals are regularly decreased (from 0.276 to 0.033) as with the rise of dose (E=0.75-78.0 R/min) as with the increase of values of V a on X-ray tube (V a =254-50 keV). One of the possible reasons of observed regularities is that X-ray conductivity in investigated crystals, especially at comparatively low V a is due predominantly to radiation of thin layer of crystal. In this case with the rise of radiation intensity there have been started to prevail the mechanism of surface quadratic recombination which leads to observed decrease of X-ray conductivity. With the rise of accelerating potential 'effective hardness' is increased, as a result of which there

  18. Paramagnetic resonance of LaGaO3: Mn single crystals grown by floating zone melting

    Science.gov (United States)

    Vazhenin, V. A.; Potapov, A. P.; Artyomov, M. Yu.; Salosin, M. A.; Fokin, A. V.; Gil'mutdinov, I. F.; Mukhamedshin, I. R.

    2016-02-01

    The EPR spectrum of Mn-doped lanthanum gallate single crystals grown by floating zone melting with optical heating has been studied. In contrast to the crystals grown according to the Czochralski method, no manganese is found in these crystals even after high-temperature annealing in air. The spectral characteristics of Fe3+ and Gd3+ centers in crystals prepared by various methods have been compared in the rhombohedral phase, and the fourth-rank nondiagonal parameters of the Fe3+ trigonal centers have been determined, as well.

  19. Growth and optical properties of Tm:GdVO{sub 4} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Y.; Akagawa, K.; Wada, S.; Tashiro, H. [Photodynamics Research Center, Sendai (Japan). Inst. of Physical and Chemical Research; Suh, S.J.; Yoon, D.H. [Photodynamics Research Center, Sendai (Japan). Inst. of Physical and Chemical Research]|[Dept. of Metallurgical Engineering, Sung Kyun Kwan Univ. (Korea, Republic of); Fukuda, T. [Photodynamics Research Center, Sendai (Japan). Inst. of Physical and Chemical Research]|[Inst. for Materials Research, Tohoku Univ. (Japan)

    1999-04-01

    Thulium-doped gadolinium vanadate (Tm:GdVO{sub 4}) single crystal has been successfully grown by a modified Czochralski (CZ) technique. Effective distribution coefficient of Tm was determined to be 0.74. Absorption characterization was performed in the 800 nm region and the maximum absorption peak was found at 799 nm for {pi} polarization. Fluorescence spectra for tuning at the maximum absorption were obtained around 1.8-2.0 {mu}m region with 100 nm bandwidth. This suggests that a Tm:GdVO{sub 4} crystal is expected as a new promising LD pumped solid-state laser in the 2 {mu}m region. (orig.) 9 refs.

  20. Growth of single crystals of BaFe12O19 by solid state crystal growth

    International Nuclear Information System (INIS)

    Fisher, John G.; Sun, Hengyang; Kook, Young-Geun; Kim, Joon-Seong; Le, Phan Gia

    2016-01-01

    Single crystals of BaFe 12 O 19 are grown for the first time by solid state crystal growth. Seed crystals of BaFe 12 O 19 are buried in BaFe 12 O 19 +1 wt% BaCO 3 powder, which are then pressed into pellets containing the seed crystals. During sintering, single crystals of BaFe 12 O 19 up to ∼130 μm thick in the c-axis direction grow on the seed crystals by consuming grains from the surrounding polycrystalline matrix. Scanning electron microscopy-energy dispersive spectroscopy analysis shows that the single crystal and the surrounding polycrystalline matrix have the same chemical composition. Micro-Raman scattering shows the single crystal to have the BaFe 12 O 19 structure. The optimum growth temperature is found to be 1200 °C. The single crystal growth behavior is explained using the mixed control theory of grain growth. - Highlights: • Single crystals of BaFe 12 O 19 are grown by solid state crystal growth. • A single crystal up to ∼130 μm thick (c-axis direction) grows on the seed crystal. • The single crystal and surrounding ceramic matrix have similar composition. • Micro-Raman scattering shows the single crystal has the BaFe 12 O 19 structure.

  1. Relaxor-PT Single Crystal Piezoelectric Sensors

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2014-07-01

    Full Text Available Relaxor-PbTiO3 piezoelectric single crystals have been widely used in a broad range of electromechanical devices, including piezoelectric sensors, actuators, and transducers. This paper reviews the unique properties of these single crystals for piezoelectric sensors. Design, fabrication and characterization of various relaxor-PT single crystal piezoelectric sensors and their applications are presented and compared with their piezoelectric ceramic counterparts. Newly applicable fields and future trends of relaxor-PT sensors are also suggested in this review paper.

  2. Preparation of TiC single crystals

    International Nuclear Information System (INIS)

    Scheerer, B.; Fink, J.; Reichardt, W.

    1975-07-01

    TiC single crystals were prepared by vertical zone melting for measurements of the phonon dispersion by inelastic neutron scattering. The influence of the starting material and of the growing conditions on the growth of the crystal were studied. The crystals were characterized by chemical methods, EMX and neutron diffraction. It was possible to grow single crystals with a volume of up to 0.6 cm 3 and mosaic spread of less then 0.4 0 . (orig.) [de

  3. Defect studies of ZnO single crystals electrochemically doped with hydrogen

    Science.gov (United States)

    Čížek, J.; Žaludová, N.; Vlach, M.; Daniš, S.; Kuriplach, J.; Procházka, I.; Brauer, G.; Anwand, W.; Grambole, D.; Skorupa, W.; Gemma, R.; Kirchheim, R.; Pundt, A.

    2008-03-01

    Various defect studies of hydrothermally grown (0001) oriented ZnO crystals electrochemically doped with hydrogen are presented. The hydrogen content in the crystals is determined by nuclear reaction analysis and it is found that already 0.3at.% H exists in chemically bound form in the virgin ZnO crystals. A single positron lifetime of 182ps is detected in the virgin crystals and attributed to saturated positron trapping at Zn vacancies surrounded by hydrogen atoms. It is demonstrated that a very high amount of hydrogen (up to ˜30at.%) can be introduced into the crystals by electrochemical doping. More than half of this amount is chemically bound, i.e., incorporated into the ZnO crystal lattice. This drastic increase of the hydrogen concentration is of marginal impact on the measured positron lifetime, whereas a contribution of positrons annihilated by electrons belonging to O-H bonds formed in the hydrogen doped crystal is found in coincidence Doppler broadening spectra. The formation of hexagonal shape pyramids on the surface of the hydrogen doped crystals by optical microscopy is observed and discussed.

  4. Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High-T and Dynamic Gas Pressure in Harsh Environments

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Hai [Clemson Univ., SC (United States); Tsai, Hai-Lung [Missouri Univ. of Science and Technology, Rolla, MO (United States); Dong, Junhang [Univ. of Cincinnati, OH (United States)

    2014-09-30

    This is the final report for the program “Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High Temperature and Dynamic Gas Pressure in Harsh Environments”, funded by NETL, and performed by Missouri University of Science and Technology, Clemson University and University of Cincinnati from October 1, 2009 to September 30, 2014. Securing a sustainable energy economy by developing affordable and clean energy from coal and other fossil fuels is a central element to the mission of The U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL). To further this mission, NETL funds research and development of novel sensor technologies that can function under the extreme operating conditions often found in advanced power systems. The main objective of this research program is to conduct fundamental and applied research that will lead to successful development and demonstration of robust, multiplexed, microstructured silica and single-crystal sapphire fiber sensors to be deployed into the hot zones of advanced power and fuel systems for simultaneous measurements of high temperature and gas pressure. The specific objectives of this research program include: 1) Design, fabrication and demonstration of multiplexed, robust silica and sapphire fiber temperature and dynamic gas pressure sensors that can survive and maintain fully operational in high-temperature harsh environments. 2) Development and demonstration of a novel method to demodulate the multiplexed interferograms for simultaneous measurements of temperature and gas pressure in harsh environments. 3) Development and demonstration of novel sapphire fiber cladding and low numerical aperture (NA) excitation techniques to assure high signal integrity and sensor robustness.

  5. Design of single-polarization wavelength splitter based on photonic crystal fiber.

    Science.gov (United States)

    Zhang, Shanshan; Zhang, Weigang; Geng, Pengcheng; Li, Xiaolan; Ruan, Juan

    2011-12-20

    A new single-polarization wavelength splitter based on the photonic crystal fiber (PCF) has been proposed. The full-vector finite-element method (FEM) is applied to analyze the single-polarization single-mode guiding properties. Splitting of two different wavelengths is realized by adjusting the structural parameters. The semi-vector three-dimensional beam propagation method is employed to confirm the wavelength splitting characteristics of the PCF. Numerical simulations show that the wavelengths of 1.3 μm and 1.55 μm are split for a fiber length of 10.7 mm with single-polarization guiding in each core. The crosstalk between the two cores is low over appreciable optical bandwidths.

  6. Piezo-optic and elasto-optic properties of monoclinic triglycine sulfate crystals.

    Science.gov (United States)

    Mytsyk, Bogdan; Demyanyshyn, Natalya; Erba, Alessandro; Shut, Viktor; Mozzharov, Sergey; Kost, Yaroslav; Mys, Oksana; Vlokh, Rostyslav

    2017-12-01

    For the first time, to the best of our knowledge, we have experimentally determined all of the components of the piezo-optic tensor for monoclinic crystals. This has been implemented on a specific example of triglycine sulfate crystals. Based on the results obtained, the complete elasto-optic tensor has been calculated. Acousto-optic figures of merit (AOFMs) have been estimated for the case of acousto-optic interaction occurring in the principal planes of the optical indicatrix ellipsoid and for geometries in which the highest elasto-optic coefficients are involved as effective parameters. It has been found that the highest AOFM value is equal to 6.8×10 -15   s 3 /kg for the case of isotropic acousto-optic interaction with quasi-longitudinal acoustic waves in the principal planes. This AOFM is higher than the corresponding values typical for canonic acousto-optic materials, which are transparent in the deep ultraviolet spectral range.

  7. Inside Perovskites: Quantum Luminescence from Bulk Cs4PbBr6 Single Crystals

    KAUST Repository

    de Bastiani, Michele; Dursun, Ibrahim; Zhang, Yuhai; Alshankiti, Buthainah; Miao, Xiaohe; Yin, Jun; Yengel, Emre; Alarousu, Erkki; Turedi, Bekir; Almutlaq, Jawaher; Saidaminov, Makhsud I.; Mitra, Somak; Gereige, Issam; Alsaggaf, Ahmed; Zhu, Yihan; Han, Yu; Roqan, Iman S.; Bredas, Jean-Luc; Mohammed, Omar F.; Bakr, Osman

    2017-01-01

    the chemistry and structure of these materials, without revealing the origins of their optical behaviour, which is contradictory to the well-studied APbX3 perovskites. In this work, we synthesize single crystals of Cs4PbBr6 0D-PRS, and investigated the origins

  8. Strong crystal field effect in ? - optical absorption study

    Science.gov (United States)

    Gajek, Z.; Krupa, J. C.

    1998-12-01

    =-1 Results of optical absorption measurements in polarized light on tetravalent neptunium diluted in a 0953-8984/10/50/021/img6 single crystal are reported. The recorded spectra are complex, pointing to the presence of an 0953-8984/10/50/021/img7 impurity. The electronic transitions assigned to the 0953-8984/10/50/021/img8 ion are interpreted in terms of the usual model, following the actual understanding of the neptunium electronic structure and independent theoretical predictions. R.m.s. deviations of the order of 0953-8984/10/50/021/img9 have been obtained for 42 levels fitted with 11 free parameters. The crystal field effect resulting from the fitting is considerably larger than that observed for the uranium ion in the same host.

  9. An injection modelocked Ti-sapphire laser for synchronous photoinjection

    International Nuclear Information System (INIS)

    Hovater, C.; Poelker, M.

    1997-01-01

    The CEBAF 4 GeV accelerator has recently begun delivering spin-polarized electrons for nuclear physics experiments. Spin-polarized electrons are emitted from a GaAs photocathode that is illuminated with pulsed laser light from a diode laser system synchronized to the injector chopping frequency (499 MHz). The present diode laser system is compact, reliable and relatively maintenance-free; however, output power is limited to less than 500 mW. In an effort to obtain higher average power and thereby prolong the effective operating lifetime of the source, they have constructed an injection modelocked Ti-sapphire laser with picosecond pulsewidths and gigahertz repetition rates. Modelocked operation is obtained through gain modulation within the Ti-sapphire crystal as a result of injection seeding with a gain-switched diode laser. Unlike conventional modelocked lasers, the pulse repetition rate of this laser can be discretely varied by setting the seed laser repetition rate equal to multiples of the Ti-sapphire laser cavity fundamental frequency. They observe pulse repetition rates from 223 MHz (fundamental) to 1,560 MHz (seventh harmonic) with average output power of 700 mW for all repetition rates. Pulsewidths ranged from 21 to 39 ps (FWHM) under various pump laser conditions

  10. Electrically Anisotropic Layered Perovskite Single Crystal

    KAUST Repository

    Li, Ting-You

    2016-04-01

    Organic-inorganic hybrid perovskites (OIHPs), which are promising materials for electronic and optoelectronic applications (1-10), have made into layered organic-inorganic hybrid perovskites (LOIHPs). These LOIHPs have been applied to thin-film transistors, solar cells and tunable wavelength phosphors (11-18). It is known that devices fabricated with single crystal exhibit the superior performance, which makes the growth of large-sized single crystals critical for future device applications (19-23). However, the difficulty in growing large-sized LOIHPs single crystal with superior electrical properties limits their practical applications. Here, we report a method to grow the centimeter-scaled LOIHP single crystal of [(HOC2H4NH3)2PbI4], demonstrating the potentials in mass production. After that, we reveal anisotropic electrical and optoelectronic properties which proved the carrier propagating along inorganic framework. The carrier mobility of in-inorganic-plane (in-plane) devices shows the average value of 45 cm2 V–1 s–1 which is about 100 times greater than the record of LOIHP devices (15), showing the importance of single crystal in device application. Moreover, the LOIHP single crystals show its ultra-short carrier lifetime of 42.7 ps and photoluminescence quantum efficiency (PLQE) of 25.4 %. We expect this report to be a start of LOIHPs for advanced applications in which the anisotropic properties are needed (24-25), and meets the demand of high-speed applications and fast-response applications.

  11. Structural and optical properties of new organic crystal 1-[4-(methylsulfanyl) phenyl]-3-(2,4,5-trimethoxyphenyl) prop-2-en-1-One for optical limiting applications

    Science.gov (United States)

    Raghavendra, S.; Anil Kumar, K. V.; Chandra Shekhara Shetty, T.; Dharmaprakash, S. M.

    2014-09-01

    A new organic crystal belonging to chalcone family 1-[4-(methylsulfanyl) phenyl]-3-(2,4,5-trimethoxyphenyl) prop-2-en-1-One (4MSTP) with molecular formula C19H20O4S has been synthesized by Claisen Schimidt condensation method. 4MSTP was crystallized by slow evaporation technique using methanol solution at ambient temperature. Crystals of 4MSTP were characterized by Fourier transform infrared (FTIR) spectroscopy, NMR spectroscopy, single crystal and powder X-ray diffraction (XRD) technique, thermal analysis and UV-Vis spectroscopy. Nonlinear optical properties of 4MSTP crystals were investigated using Nd:YAG laser at 532 nm wavelength. The presence of functional groups were confirmed by FTIR and the structural elucidation was done using proton and carbon NMR spectral analysis. The X-ray diffraction peaks are indexed by the least square fit method. From the single crystal XRD study it is found that 4MSTP crystallizes in monoclinic system with a centro symmetric space group P21/c. The unit cell parameters of the crystal are: a = 19.2413(6) Å, b = 8.9504(3) Å, c = 10.3608(4) Å, α = 90°, β = 104.45°(2) and γ = 90°. Linear optical studies were carried out using UV visible spectral technique. The studies revealed that the 4MSTP crystals can be exploited for the nonlinear optical applications. TGA-DSC experiments indicated that the melting point of the material is 165.91 °C and the crystals showed absence of phase transition before melting point. Calculated excited state absorption (σex) is greater than the ground state absorption (σg) and thus the condition for Reverse Saturable Absorption (RSA) is achieved in 4MSTP. The open aperture Z-Scan curve showed minimum transmittance at the focus and hence 4MSTP crystals have maximum nonlinear absorption. The variation of nonlinear transmission with input intensity of laser showed that 4MSTP crystals can be used as an optical limiter.

  12. Studies on the structural, optical and dielectric properties of samarium coordinated with salicylic acid single crystal

    Science.gov (United States)

    Singh, Harjinder; Slathia, Goldy; Gupta, Rashmi; Bamzai, K. K.

    2018-04-01

    Samarium coordinated with salicylic acid was successfully grown as a single crystal by low temperature solution technique using mixed solvent of methanol and water in equal ratio. Structural characterization was carried out by single crystal X-ray diffraction analysis and it crystallizes in centrosymmetric space group P121/c1. FTIR and UV-Vis-NIR spectroscopy confirmed the compound formation and help to determine the mode of binding of the ligand to the rare earth-metal ion. Dielectric constant and dielectric loss have been measured over the frequency range 100 Hz - 30MHz. The decrease in dielectric constant with increases in frequency is due to the transition from interfacial polarization to dipolar polarization. The small value of dielectric constant at higher frequency ensures that the crystal is good candidate for NLO devices. Dielectric loss represents the resistive nature of the material.

  13. Detection of beryllium treatment of natural sapphires by NRA

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, P.C., E-mail: carolina.gutierrez@uam.e [Centro de Micro-Analisis de Materiales (CMAM), Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Ynsa, M.-D.; Climent-Font, A. [Centro de Micro-Analisis de Materiales (CMAM), Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Dpto. Fisica Aplicada C-12, Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Calligaro, T. [Centre de Recherche et de Restauration des musees de France C2RMF, CNRS-UMR171, 14 quai Francois Mitterrand, 75001 Paris (France)

    2010-06-15

    Since the 1990's, artificial treatment of natural sapphires (Al{sub 2}O{sub 3} crystals coloured by impurities) by diffusion of beryllium at high temperature has become a growing practice. This process permits to enhance the colour of these gemstones, and thus to increase their value. Detection of such a treatment - diffusion of tens of {mu}g/g of beryllium in Al{sub 2}O{sub 3} crystals - is usually achieved using high sensitivity techniques like laser-ablation inductively coupled plasma mass spectrometry (LA-ICP/MS) or laser-induced breakdown spectrometry (LIBS) which are unfortunately micro-destructive (leaving 50-100-{mu}m diameter craters on the gems). The simple and non-destructive alternative method proposed in this work is based on the nuclear reaction {sup 9}Be({alpha}, n{gamma}){sup 12}C with an external helium ion beam impinging on the gem directly placed in air. The 4439 keV prompt {gamma}-ray tagging Be atoms are detected with a high efficiency bismuth germanate scintillator. Beam dose is monitored using the 2235 keV prompt {gamma}-ray produced during irradiation by the aluminium of the sapphire matrix through the {sup 27}Al({alpha}, p{gamma}){sup 30}Si nuclear reaction. The method is tested on a series of Be-treated sapphires previously analyzed by LA-ICP/MS to determine the optimal conditions to obtain a peak to background appropriate to reach the required {mu}g/g sensitivity. Using a 2.8-MeV external He beam and a beam dose of 200 {mu}C, beryllium concentrations from 5 to 16 {mu}g/g have been measured in the samples, with a detection limit of 1 {mu}g/g.

  14. Possible pitfalls in search of magnetic order in thin films deposited on single crystalline sapphire substrates

    International Nuclear Information System (INIS)

    Salzer, R.; Spemann, D.; Esquinazi, P.; Hoehne, R.; Setzer, A.; Schindler, K.; Schmidt, H.; Butz, T.

    2007-01-01

    We have studied the field and temperature dependence of the magnetic moment of single crystalline sapphire substrates with different surface orientations. All the substrates show a ferromagnetic behavior that partially changes after surface cleaning. The amount of magnetic impurities in the substrates was determined by particle induced X-ray emission. The overall analysis of the data indicates that the magnetic impurities very likely contribute to the measured ferromagnetic behavior but does not rule out completely intrinsic contributions. Our work stresses the necessity to use other than bulk characterization methods for the study of weak ferromagnetic signals of thin films grown on oxide substrates

  15. High-quality single crystal growth and magnetic property of Mn4Ta2O9

    Science.gov (United States)

    Cao, Yiming; Xu, Kun; Yang, Ya; Yang, Wangfan; Zhang, Yuanlei; Kang, Yanru; He, Xijia; Zheng, Anmin; Liu, Mian; Wei, Shengxian; Li, Zhe; Cao, Shixun

    2018-06-01

    A large-size single crystal of Mn4Ta2O9 with ∼3.5 mm in diameter and ∼65 mm in length was successfully grown for the first time by a newly designed one-step method based on the optical floating zone technique. Both the clear Laue spots and sharp XRD Bragg reflections suggest the high quality of the single crystal. In Mn4Ta2O9 single crystal, an antiferromagnetic phase transition was observed below Néel temperature 102 K along c axis, which is similar to the isostructural compound Mn4Nb2O9, but differs from the isostructural Co4Nb2O9. Relative dielectric constant at 30 kOe suggests that no magnetoelectric coupling exists in Mn4Ta2O9.

  16. Phase transitions in A4Li(HSO4)3(SO4); A = Rb, K: Single crystal X ...

    Indian Academy of Sciences (India)

    Unknown

    Single crystal studies on RLHS at room temperature (293 K) reported earlier5 showed that the crystals are optically laevorotatory and belong to the enantiomorphous space group P41. However, an analysis of the diffraction data based on the value of enantio- morph polarity parameter during refinement suggested that the ...

  17. Crystal growth and scintillation properties of Pr-doped SrI2 single crystals

    Science.gov (United States)

    Yokota, Yuui; Ito, Tomoki; Yoshino, Masao; Yamaji, Akihiro; Ohashi, Yuji; Kurosawa, Shunsuke; Kamada, Kei; Yoshikawa, Akira

    2018-04-01

    Pr-doped SrI2 (Pr:SrI2) single crystals with various Pr concentrations were grown by the halide-micro-pulling-down (H-μ-PD) method, and the scintillation properties were investigated. Pr1%:SrI2 single crystal with high transparency could be grown by the H-μ-PD method while Pr2, 3 and 5%:SrI2 single crystals included some cracks and opaque parts. In the photoluminescence spectrum of the Pr1%:SrI2 single crystal, an emission peak originated from the Pr3+ ion was observed around 435 nm while the radioluminescence spectra showed an emission peak around 535 nm for the undoped SrI2 and Pr:SrI2 single crystals. Light yields of Pr1, 2, 3 and 5%:SrI2 single crystals under γ-ray irradiation were 7700, 8700, 7200 and 6700 photons/MeV, respectively. Decay times of Pr1 and 2%:SrI2 single crystals under γ-ray irradiation were 55.9 and 35.0 ns of the fast decay component, and 435 and 408 ns of the slow decay component, respectively.

  18. Growth and characterization of an efficient new NLO single crystal L-phenylalanine D-methionine for frequency conversion and optoelectronic applications

    Science.gov (United States)

    Sangeetha, P.; Jayaprakash, P.; Nageshwari, M.; Rathika Thaya Kumari, C.; Sudha, S.; Prakash, M.; Vinitha, G.; Lydia Caroline, M.

    2017-11-01

    Optically active single crystals of L-phenylalanine D-methionine (LPDM) were grown by slow evaporation technique by co-crystallization of amino acids L-phenylalanine and D-methionine in water. The unit cell dimensions have been identified from single crystal X-ray diffraction technique. The existences of various hydrocarbyls were examined by FTIR and FT-Raman spectroscopy. The carbon and hydrogen environment of the grown crystals were analyzed by FT NMR spectrum. The optical absorption studies show that the crystal is transparent in the visible region with a lower cut-off wavelength of 259 nm and there by optical band gap energy Eg is calculated to be 5.35 eV. The Urbach energy, extinction coefficient, reflectance were calculated from UV-absorption data. Further, the thermal stability and accurate melting point has been investigated by TG/DSC techniques. The Kurtz powder SHG was confirmed using Nd:YAG laser with fundamental wavelength of 1064 nm. The dielectric behavior of the specimen has been determined for various temperatures (313 K, 333 K, 353 K, 373 K) at different frequencies. Fluorescence study and the time resolved decay calculation was also performed for the LPDM crystal. Optical nonlinear susceptibility was measured in LPDM and the real and imaginary part of χ3 was evaluated by Z-scan technique using open and closed apertures.

  19. Photoluminescence and lasing properties of MAPbBr3 single crystals grown from solution

    Science.gov (United States)

    Aryal, Sandip; Lafalce, Evan; Zhang, Chuang; Zhai, Yaxin; Vardeny, Z. Valy

    Recent studies of solution-grown single crystals of inorganic-organic hybrid lead-trihalide perovskites have suggested that surface traps may play a significant role in their photophysics. We study electron-hole recombination in single crystal MAPbBr3 through such trap states using cw photoluminescence (PL) and ps transient photoinduced absorption (PA) spectroscopies. By varying the depth of the collecting optics we examined the contributions from surface and bulk radiative recombination. We found a surface dominated PL band at the band-edge that is similar to that observed from polycrystalline thin films, as well as a weaker red-shifted emission band that originates from the bulk crystal. The two PL bands are distinguished in their temperature, excitation intensity and polarization dependencies, as well as their ps dynamics. Additionally, amplified spontaneous emission and crystal-related cavity lasing modes were observed in the same spectral range as the PL band assigned to the surface recombination. This work was funded by AFOSR through MURI Grant RA 9550-14-1-0037.

  20. Bent crystal X-ray optics for the diagnosis and applications of laser-produced plasmas

    International Nuclear Information System (INIS)

    Loetzsch, Robert

    2012-01-01

    The present thesis discussed several aspects of X-ray optics based on bent crystals and a number of applications of these optics. First, a deeper insight into the reflection properties of elastically bent perfect crystal optics was gained by the consideration of all deformation effects. It was shown that the reflection properties depend on the lateral position on the crystal, an effect that was not addressed before, neither experimentally nor theoretically. To investigate this effect, an apparatus for the measurement of Bragg angles of bent crystals with high angular resolution was built. It was measured that the lattice plane distances of two-dimensionally bent crystals vary laterally by up to 10 -4 . This effect has to be considered in high resolution X-ray spectroscopy and imaging with these bent crystals. It can explain discrepancies in theoretical and experimental spectrometer resolution with spherically bent crystals. Besides these principal investigations, in this thesis a number of X-ray optics were presented that demonstrate the application potential of bent crystal optics. This includes two optics that are used in the field of applications of laser-produced plasmas as high repeating hard X-ray sources. It was shown that an X-ray spectrometer based on full cylinder rings of highly oriented pyrolytic graphite is capable to record the rather weak single shot pulses from a high repeating 1 er-plasma X-ray source. This is possible due to the high collection efficiency of the instrument of up to 5.10 -4 . Furthermore, X-ray optics based on toroidally bent crystals that make it possible to spectrally select a bandwidth of ∝1 eV and focus the ultrashort X-ray pulses from such a laser-plasma source, were designed, prepared and characterized. It was shown that these bent crystals provide the calculated integrated reflectivity, the predicted bandwidth and focus to spot sizes smaller than 60 μm. A novel application of toroidally bent crystals was pointed out: a

  1. Structure property relationship of a new nonlinear optical organic crystal: 1-(3,4-Dimethoxyphenyl-3-(3-fluorophenylprop-2-en-1-one for optical power limiting applications

    Directory of Open Access Journals (Sweden)

    S. Raghavendra

    Full Text Available A new organic potential nonlinear optical (NLO material 1-(3,4-dimethoxyphenyl-3-(3-fluorophenylprop-2-en-1-one (DMP3FP is crystallized in acetone. The single crystal X-ray diffraction data shows that material crystallizes into centro-symmetric orthorhombic space group Pbca with a = 15.6552(6 Å, b = 8.5571(3 Å, c = 20.7697(7 Å. The functional groups in DMP3FP molecule are identified by Fourier Transfer Infrared (FTIR spectra. The thermal stability and melting point are determined using thermo gravimetric analysis/differential thermal analysis (TGA/DTA. Using UV Visible spectral studies direct band gap energy of the crystal is determined to be 3.19 eV. The nonlinear absorption coefficient and optical power limiting of the crystal was studied using Z-scan technique. The crystal exhibits a self-focusing effect at a wavelength of 532 nm showing optical limiting and reverse saturable absorption by having excited state absorption coefficient greater than ground state absorption coefficient. Keywords: Nonlinear, Optical power limiting, Z-scan, Self-focusing

  2. Integrated Photonic Neural Probes for Patterned Brain Stimulation

    Science.gov (United States)

    2017-08-14

    only 250µm wide, identical to the diameter of the optical fiber that couples to it. Subplot (4c) shows an unscaled schematic drawing of the layer...demultiplexing, we used a mode- locked Ti:Sapphire femtosecond laser to pump in a single pass fashion a thin non-linear crystal of BBO (Beta Barium...Borate), to produce a second harmonic signal as shown in Figure (9a). The mode- locked Ti:Sapphire laser is tuned at 946nm wavelength with 70fs pulse

  3. Optical and magneto-optical effects in Hg{sub 1-x}Cd{sub x}Cr{sub 2}Se{sub 4} (0 ⩽ x ⩽ 1) single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sukhorukov, Yu. P., E-mail: suhorukov@imp.uran.ru; Telegin, A. V.; Bebenin, N. G.; Zainullina, R. I.; Mostovshchikova, E. V.; Viglin, N. A. [Ural Branch, Russian Academy of Sciences, Mikheev Institute of Metal Physics (Russian Federation); Gan’shina, E. A.; Zykov, G. S. [Moscow State University (Russian Federation); Fedorov, V. A. [Russian Academy of Sciences, Kurnakov Institute of Inorganic Chemistry (Russian Federation); Menshchikova, T. K.; Buchkevich, A. A. [Ural Branch, Russian Academy of Sciences, Mikheev Institute of Metal Physics (Russian Federation)

    2015-09-15

    The concentration, temperature, and magnetic-field dependences of the magnetoreflection and magnetotransmission of natural light in the infrared spectral range and the Kerr effect in single crystals of ferromagnetic Hg{sub 1-x}Cd{sub x}Cr{sub 2}Se{sub 4} (0 ⩽ x ⩽ 1) spinels have been studied. A relationship of the magneto-optical properties to the electronic band structure of spinels has been established. The most significant changes in the spectra of magnetoreflection, magnetotransmission, and the Kerr effect are shown to be observed for 0.1 < x < 0.25 and are attributable to a rearrangement of the band structure as the composition changes.

  4. Linear and nonlinear optical properties of borate crystals as ...

    Indian Academy of Sciences (India)

    Unknown

    crystal series, with an accuracy acceptable for materials development/design, and answer the questions often ... Optical property; nonlinear optical crystals; first principles calculation. 1. ..... system, and is not in concept suitable to excitation pro-.

  5. Synthesis and characterization of p-type boron-doped IIb diamond large single crystals

    International Nuclear Information System (INIS)

    Li Shang-Sheng; Li Xiao-Lei; Su Tai-Chao; Jia Xiao-Peng; Ma Hong-An; Huang Guo-Feng; Li Yong

    2011-01-01

    High-quality p-type boron-doped IIb diamond large single crystals are successfully synthesized by the temperature gradient method in a china-type cubic anvil high-pressure apparatus at about 5.5 GPa and 1600 K. The morphologies and surface textures of the synthetic diamond crystals with different boron additive quantities are characterized by using an optical microscope and a scanning electron microscope respectively. The impurities of nitrogen and boron in diamonds are detected by micro Fourier transform infrared technique. The electrical properties including resistivities, Hall coefficients, Hall mobilities and carrier densities of the synthesized samples are measured by a four-point probe and the Hall effect method. The results show that large p-type boron-doped diamond single crystals with few nitrogen impurities have been synthesized. With the increase of quantity of additive boron, some high-index crystal faces such as {113} gradually disappear, and some stripes and triangle pits occur on the crystal surface. This work is helpful for the further research and application of boron-doped semiconductor diamond. (cross-disciplinary physics and related areas of science and technology)

  6. Characteristics of a Ti:sapphire laser pumped by a Nd:YAG laser and its analysis. Nd:YAG laser reiki Ti:sapphire laser no dosa tokusei to sono kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Okada, T.; Masumoto, J.; Mizunami, T.; Maeda, M.; Muraoka, K. (Kyushu Univ., Fukuoka (Japan). Faculty of Engineering)

    1991-06-29

    Although Ti: Sapphire expects of a possibility of being a light source much superior to a dye laser having been used as a wavelength variable laser for spectral analyses, it has a limitation that it does not oscillate directly in the visible and ultraviolet regions. In order to develop a light source that is synchronizable over ultraviolet-near infrared regions, by means of combining a Ti: Sapphire laser of a high peak power, comprising an oscillator and a multistage amplifier, with a non-linear frequency conversion method for harmonic generation and Raman conversion, a prototype Ti:Sapphire laser that is excited by YAG laser second harmonic, and that synchronizes with a prism was fabricated, and its operational characteristics were investigated. As a result, an output energy of 35.6 mJ at a maximum was obtained at a wavelength of 773 nm against an excitation energy of 129 mJ, a conversion efficiency of 38.2% was obtained against the absorption energy of the crystals, and a continuous synchronism was achieved over 750 to 900 nm. 4 refs., 9 figs., 1 tab.

  7. Comparative optical study of thulium-doped YVO4 , GdVO4 , and LuVO4 single crystals

    Science.gov (United States)

    Lisiecki, R.; Solarz, P.; Dominiak-Dzik, G.; Ryba-Romanowski, W.; Sobczyk, M.; Černý, Pavel; Šulc, Jan; Jelínková, Helena; Urata, Yoshiharu; Higuchi, Mikio

    2006-07-01

    YVO4:Tm3+ crystals grown by the Czochralski technique and GdVO4:Tm3+ and LuVO4:Tm3+ crystals grown by the floating-zone technique were investigated using methods of optical spectroscopy. Polarized absorption and emission spectra were recorded at room temperature and at 6K . The crystal-field analysis was performed assuming the D2d site symmetry for Tm3+ ions. In this way the missing crystal-field components of the H63 ground multiplet were located. Room temperature absorption spectra were analyzed in the framework of the Judd-Ofelt theory. Evaluated radiative lifetimes of luminescent levels of Tm3+ follow a general trend diminishing in agreement with the sequence: YVO4:Tm3+→GdVO4:Tm3+→LuVO4:Tm3+ . Luminescence lifetimes measured for the systems under study are similar except for the F43 lifetime, which appears to be surprisingly short for LuVO4:Tm3+ . Anisotropy of optical spectra is particularly pronounced in LuVO4:Tm3+ . Peak absorption cross section for the band relevant for optical pumping at about 805nm is roughly three times higher for π polarization. Stimulated emission cross sections for the F43-H63 transition near 1800nm were evaluated using the reciprocity method. The diode-pumped continuous wave laser operation in GdVO4:Tm3+ with a slope efficiency of up to 40% is demonstrated. In LuVO4:Tm3+ the diode-pumped laser oscillation in a pulsed mode was observed.

  8. Electrically Anisotropic Layered Perovskite Single Crystal

    KAUST Repository

    Li, Ting-You

    2016-01-01

    -23). However, the difficulty in growing large-sized LOIHPs single crystal with superior electrical properties limits their practical applications. Here, we report a method to grow the centimeter-scaled LOIHP single crystal of [(HOC2H4NH3)2PbI4], demonstrating

  9. Structural, vibrational and thermal characterization of phase transformation in L-histidinium bromide monohydrate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Moura, G.M. [Universidade Federal do Maranhão, CCSST, Imperatriz, MA, 65900-410 (Brazil); Universidade Federal do Sul e Sudeste do Pará, ICEN, Marabá, PA 68505-080 (Brazil); Carvalho, J.O. [Universidade Federal do Maranhão, CCSST, Imperatriz, MA, 65900-410 (Brazil); Instituto Federal do Tocantins, Araguaína, TO, 77.826-170 (Brazil); Silva, M.C.D.; Façanha Filho, P.F. [Universidade Federal do Maranhão, CCSST, Imperatriz, MA, 65900-410 (Brazil); Santos, A.O. dos, E-mail: adenilson1@gmail.com [Universidade Federal do Maranhão, CCSST, Imperatriz, MA, 65900-410 (Brazil)

    2015-09-01

    L-Histidinium bromide monohydrate (LHBr) single crystal is a nonlinear optical material. In this work the high temperature phase transformation and the thermal stability of single crystals of LHBr was investigated by X-ray diffraction, thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry and Raman spectroscopy. The results showed the LHBr phase transformation of orthorhombic (P2{sub 1}2{sub 1}2{sub 1}) to monoclinic system (P 1 2 1) at 120 °C, with the lattice parameters a = 12.162(1) Å, b = 16.821(2) Å, c = 19.477(2) Å and β = 108.56(2)°. These techniques are complementary and confirm the structural phase transformation due to loss water of crystallization. - Highlights: • -histidinium bromide single crystal was grown by slow evaporation technique. • X-ray diffraction characterize the high-temperature phase transformation. • The structural phase transformation occur due to loss of water of crystallization. • The LHBr thermal expansion coefficients exhibit an anisotropic behavior.

  10. Novel Modified Optical Fibers for High Temperature In-Situ Miniaturized Gas Sensors in Advanced Fossil Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Pickrell, Gary [Virginia Polytechnic Institute & State University, Blacksburg, VA (United States); Scott, Brian [Virginia Polytechnic Institute & State University, Blacksburg, VA (United States)

    2014-06-30

    This report covers the technical progress on the program “Novel Modified Optical Fibers for High Temperature In-Situ Miniaturized Gas Sensors in Advanced Fossil Energy Systems”, funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Materials Science & Engineering and Electrical & Computer Engineering Departments at Virginia Tech, and summarizes technical progress from July 1st, 2005 –June 30th, 2014. The objective of this program was to develop novel fiber materials for high temperature gas sensors based on evanescent wave absorption in optical fibers. This project focused on two primary areas: the study of a sapphire photonic crystal fiber (SPCF) for operation at high temperature and long wavelengths, and a porous glass based fiber optic sensor for gas detection. The sapphire component of the project focused on the development of a sapphire photonic crystal fiber, modeling of the new structures, fabrication of the optimal structure, development of a long wavelength interrogation system, testing of the optical properties, and gas and temperature testing of the final sensor. The fabrication of the 6 rod SPCF gap bundle (diameter of 70μm) with a hollow core was successfully constructed with lead-in and lead-out 50μm diameter fiber along with transmission and gas detection testing. Testing of the sapphire photonic crystal fiber sensor capabilities with the developed long wavelength optical system showed the ability to detect CO2 at or below 1000ppm at temperatures up to 1000°C. Work on the porous glass sensor focused on the development of a porous clad solid core optical fiber, a hollow core waveguide, gas detection capabilities at room and high temperature, simultaneous gas species detection, suitable joining technologies for the lead-in and lead-out fibers and the porous sensor, sensor system sensitivity improvement, signal processing improvement, relationship between pore structure and fiber

  11. Growth of tourmaline single crystals containing transition metal elements in hydrothermal solutions

    Science.gov (United States)

    Setkova, Tatiana; Shapovalov, Yury; Balitsky, Vladimir

    2011-03-01

    Interest in the growth of tourmaline single crystals is based on the promising piezoelectric and pyroelectric properties of this material compared to quartz crystals currently in use. Moreover, synthetic tourmaline can be used as a substitute for the natural stone in the jewelry industry similar to other synthetic analogues of gemstones. Single crystals of colored Co-, Ni-, Fe-, (Ni,Cr)-, (Ni,Fe)-, and (Co,Ni,Cr)-containing tourmalines with concentration of transition metal elements up to 16 wt% on a seed have been grown from complex boron-containing hydrothermal solutions at a range of temperatures 400-750 °C and pressures 100 MPa. Experiments were conducted under conditions of a thermal gradient in titanium and chromium-nickel autoclaves. Tourmaline growth on a seed crystal occurs only if separate tourmaline-forming components (monocrystalline corundum and quartz bars) are used as charge. All tourmalines specified above grow in analogous (+) direction of the optical axis with a speed of 0.05 mm/day by faces of the trigonal pyramid, except tourmalines containing chromium. They grow in analogous (+0001) direction with a speed 0.05 mm/day, and in antilogous (-0001) direction with a speed of 0.01 mm/day by faces of the trigonal pyramid and in prism direction with a speed of 0.001 mm/day. Along with the large single crystals, a great amount of finest (30-150 μm in size) tourmaline crystals was formed during the runs by spontaneous nucleation both on the surface of the seed crystals and in the charge.

  12. Coloration dependence in the thermoluminescence properties of the double doped NaCl single crystals under gamma irradiation

    International Nuclear Information System (INIS)

    Sanchez-Mejorada, G.; Gelover-Santiago, A.L.; Frias, D.

    2006-01-01

    In this work the behaviour of calcium manganese doped NaCl single crystals under gamma irradiation is reported. Various single crystals of NaCl doped with Ca and Mn have been irradiated at different doses with ionising radiation. The production of defects has been correlated to the increase in the intensity of the thermo luminescent glow curve as a function of doses. The glow curves intensity as a function of doses shows the potential use of these materials as dosimeters. Optical properties of such crystals after irradiation with gamma rays have also been studied; results have shown their potentiality as a good detector and optical store memory devices. Since the creations of colour centres by photons with energy less than the band gap energy has been detected also in ns 2 -ion doped alkali halides. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Advanced Neutron Moderators for the ESS

    DEFF Research Database (Denmark)

    Schönfeldt, Troels

    . The main increases in thermal and cold intensity are achieved by upscaling the power density of reactors or proton beam power of spallation sources. Reactor development saturated in the 1960s with the construction of the continuous, compact, high-power-density reactors HFIR, Oak Ridge, and ILL, Grenoble...... crystal. The experiment compares single-crystal sapphire, sapphire powder and void. Sapphire was used, since no other single-crystal candidates (diamond, pyrolytic graphite and lithium uoride) could be obtained within the cost and time constraints of the experiment. Unfortunately, sapphire does...

  14. Orientation effect on recovery and recrystallization of cold rolled niobium single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, R. [Center for Accelerated Maturation of Materials, Department of Materials Science and Engineering, Ohio State University, Columbus, OH 43210 (United States)], E-mail: rajagopalan.5@osu.edu; Viswanathan, G.B.; Levit, V.I.; Fraser, H.L. [Center for Accelerated Maturation of Materials, Department of Materials Science and Engineering, Ohio State University, Columbus, OH 43210 (United States)

    2009-05-15

    Single crystal sheets of niobium with initial orientations of (0 0 1) [11-bar0], (1 1 0) [11-bar 0] and (1 1 1) [11-bar0] were rolled at room temperature in the strain range of 25-50%. The deformed specimens were vacuum annealed at temperatures of 800 deg. C, 1000 deg. C, and 1200 deg. C for 3 h. TEM, SEM-OIM and optical microscopy revealed orientation stability in (0 0 1) and (1 1 0) rolled samples with no recrystallization observed after annealing. Samples rolled along (1 1 1) partially recrystallized after annealing at 1000 deg. C and 1200 deg. C. A relatively small increase was observed in hardness of (0 0 1) rolled crystals between 25% and 50% strain, implying low work hardening rates. (1 1 1) rolled samples showed higher hardening rates, and enhanced recovery in hardness values after annealing, due to partial recrystallization. Conditions have been identified for the deformation and annealing of niobium single crystals, enabling the preservation of single crystal structure and near-complete recovery of mechanical properties. A simple crystallographic model is proposed, giving an explanation for the observed orientation stability in (0 0 1) and (1 1 0) rolled samples, and the tendency towards instability and recrystallization in (1 1 1) rolled samples.

  15. Optically induced structural phase transitions in ion Coulomb crystals

    DEFF Research Database (Denmark)

    Horak, Peter; Dantan, Aurelien Romain; Drewsen, Michael

    2012-01-01

    We investigate numerically the structural dynamics of ion Coulomb crystals confined in a three-dimensional harmonic trap when influenced by an additional one-dimensional optically induced periodical potential. We demonstrate that transitions between thermally excited crystal structures, such as b......We investigate numerically the structural dynamics of ion Coulomb crystals confined in a three-dimensional harmonic trap when influenced by an additional one-dimensional optically induced periodical potential. We demonstrate that transitions between thermally excited crystal structures...

  16. Properties of single crystal beta''-aluminas

    International Nuclear Information System (INIS)

    Bates, J.B.; Brown, G.M.; Kaneda, T.; Brundage, W.E.; Wang, J.C.; Engstrom, H.

    1979-01-01

    Large single crystals of sodium beta''-alumina were grown by slow evaporation of Na 2 O at 1690 0 C from a mixture of Na 2 CO 3 , MgO, and Al 2 O 3 . Polarized Raman measurements were made on the Na β'' single crystals and on single crystals of Li, K, Rb, and Ag β'' prepared by ion exchange of Na β''. The low frequency Raman spectra of Na, K, Rb, and Ag β'' contained four or more bands due to vibrations of the mobile cations. These results were analyzed by assuming the spectra to be due to the normal modes of a defect cluster consisting of a cation vacancy surrounded by three cations. From model calculations, the Raman band of Na β'' at 33 cm -1 is assigned to the attempt mode for diffusion of Na + ions. The structure of a Ag β'' single crystal was investigated by neutron diffraction, and 20% of the Ag + ion sites were found to be vacant

  17. Ultra-large single crystals by abnormal grain growth.

    Science.gov (United States)

    Kusama, Tomoe; Omori, Toshihiro; Saito, Takashi; Kise, Sumio; Tanaka, Toyonobu; Araki, Yoshikazu; Kainuma, Ryosuke

    2017-08-25

    Producing a single crystal is expensive because of low mass productivity. Therefore, many metallic materials are being used in polycrystalline form, even though material properties are superior in a single crystal. Here we show that an extraordinarily large Cu-Al-Mn single crystal can be obtained by abnormal grain growth (AGG) induced by simple heat treatment with high mass productivity. In AGG, the sub-boundary energy introduced by cyclic heat treatment (CHT) is dominant in the driving pressure, and the grain boundary migration rate is accelerated by repeating the low-temperature CHT due to the increase of the sub-boundary energy. With such treatment, fabrication of single crystal bars 70 cm in length is achieved. This result ensures that the range of applications of shape memory alloys will spread beyond small-sized devices to large-scale components and may enable new applications of single crystals in other metallic and ceramics materials having similar microstructural features.Growing large single crystals cheaply and reliably for structural applications remains challenging. Here, the authors combine accelerated abnormal grain growth and cyclic heat treatments to grow a superelastic shape memory alloy single crystal to 70 cm.

  18. Transfiguring structural, optical and dielectric properties of cadmium thiourea acetate crystal by the addition of L-threonine for laser assisted device applications

    Science.gov (United States)

    Kulkarni, Rupali B.; Anis, Mohd; Hussaini, S. S.; Shirsat, Mahendra D.

    2018-03-01

    Present investigation reports the growth of pure and L-threonine (LT) doped cadmium thiourea acetate (CTA) crystals by slow solution evaporation technique followed by structural, optical and dielectric characterization studies. A bulk single crystal of LT-CTA has been grown at temperature 38 °C. The single crystal x-ray diffraction technique has been employed to confirm the structural parameters of pure and LT doped CTA crystals. The increase in optical transparency of LT-CTA crystal was ascertained in the range of 200 to 900 nm using UV-visible spectral analysis. The widened optical band gap of the LT-CTA crystal is found to be 4.7 eV. Pure and doped crystals are subjected to FT-IR analysis to indicate the presence of functional groups quantitatively. Appreciable enhancement in second harmonic generation (SHG) efficiency of LT-CTA crystal with reference to parent CTA was confirmed from Kurtz-Perry SHG test (1.31 times of CTA crystal). The assertive influence of LT on electrical properties of grown crystals has been investigated in the temperature range 35 °C-120 °C. Electronic purity and the color centered photoluminescence emission nature of pure and IA-CTA crystals were justified by luminescence analysis. With the aid of single beam Z-scan analysis, the Kerr lensing nonlinearity was identified and the magnitude of TONLO parameters has been determined. The cubic susceptibility (χ3) and figure of merit (FOM) was found to be 4.81 × 10-4esu and 978.35. Results vitalize LT-CTA for laser stabilization systems.

  19. Isotopically pure single crystal epitaxial diamond films and their preparation

    International Nuclear Information System (INIS)

    Banholzer, W.F.; Anthony, T.R.; Williams, D.M.

    1992-01-01

    The present invention is directed to the production of single crystal diamond consisting of isotopically pure carbon-12 or carbon-13. In the present invention, isotopically pure single crystal diamond is grown on a single crystal substrate directly from isotopically pure carbon-12 or carbon-13. One method for forming isotopically pure single crystal diamond comprises the steps of placing in a reaction chamber a single substrate heated to an elevated diamond forming temperature. Another method for forming isotopically pure single crystal diamond comprises diffusing isotopically pure carbon-12 or carbon-13 through a metallic catalyst under high pressure to a region containing a single crystal substrate to form an isotopically pure single crystal diamond layer on said single crystal substrate

  20. Optical absorption of selenite single crystals subjected to high electric fields and irradiated with X-rays or γ-rays

    International Nuclear Information System (INIS)

    Mishra, Sakuntala; Rao, A.V.K.; Rao, K.V.

    1988-01-01

    Measurements of the optical absorption coefficient of selenite single crystals show two peaks at 236 and 400 nm when plotted as a function of wavelength. These peaks decrease with increasing irradiation time for both γ and X-rays. Subsequent thermal bleaching increases the absorption coefficient at all wavelengths and flattens out the peaks at 140 0 C and 330 0 C respectively. The imposition of an a.c. or d.c. field prior to irradiation preserves the thermal bleaching characteristics with an overall increase in absorption coefficient. These effects are attributed to two different types of bond formed by water of crystallization giving rise to the two absorption peaks. Irradiation may destroy some of the bands of loosely bound water molecules near defect regions leading to a decrease in absorption. Thermal bleaching removes water molecules reducing the transparency of the samples, the more strongly bound molecules being removed at the higher temperature. Irradiation after a.c. or d.c. field treatment may introduce more defect regions enabling the removal of more water molecules by bleaching and hence increasing the absorption. (U.K.)

  1. Biaxial crystal-based optical tweezers

    DEFF Research Database (Denmark)

    Angelsky, Oleg V.; Maksimyak, Andrew P.; Maksimyak, Peter P.

    2010-01-01

    We suggest an optical tweezer setup based on an optically biaxial crystal. To control movements of opaque particles, we use shifts. The results of experimental studies are reported which are concerned with this laser tweezer setup. We demonstrate a movement of microparticles of toner using...... a singular-optical trap, rotation of particles due to orbital angular momentum of the field, and converging or diverging of two different traps when changing transmission plane of polariser at the input of our polarisation interferometer....

  2. All-optical tunable photonic crystal cavity

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    We demonstrate an ultra-small photonic crystal cavity with two resonant modes. An all-optical tuning operation based on the free-carrier plasma effect is, for the first time, realized utilizing a continuous wave light source. The termo-optical effect is minimized by isoproponal infiltration...

  3. Optical Cladding Waveguides in Dielectric Crystals Produced by Femtosecond Laser Inscription

    Directory of Open Access Journals (Sweden)

    Chen Feng

    2013-11-01

    Full Text Available In this work, the recent progress of our research on optical cladding waveguides in dielectric crystals produced by femtosecond laser inscription has been overviewed. With different scales at cross sections, the cladding waveguides support guidance from single mode to highly multi-modes, and work for wavelength till mid-infrared regimes. Applications of the fabricated cladding structures as new integrated light sources are introduced.

  4. Large single-crystal diamond substrates for ionizing radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Girolami, Marco; Bellucci, Alessandro; Calvani, Paolo; Trucchi, Daniele M. [Istituto di Struttura della Materia (ISM), Consiglio Nazionale delle Ricerche (CNR), Sede Secondaria di Montelibretti, Monterotondo Stazione, Roma (Italy)

    2016-10-15

    The need for large active volume detectors for ionizing radiations and particles, with both large area and thickness, is becoming more and more compelling in a wide range of applications, spanning from X-ray dosimetry to neutron spectroscopy. Recently, 8.0 x 8.0 mm{sup 2} wide and 1.2 mm thick single-crystal diamond plates have been put on the market, representing a first step to the fabrication of large area monolithic diamond detectors with optimized charge transport properties, obtainable up to now only with smaller samples. The more-than-double thickness, if compared to standard plates (typically 500 μm thick), demonstrated to be effective in improving the detector response to highly penetrating ionizing radiations, such as γ-rays. Here we report on the first measurements performed on large active volume single-crystal diamond plates, both in the dark and under irradiation with optical wavelengths (190-1100 nm), X-rays, and radioactive γ-emitting sources ({sup 57}Co and {sup 22}Na). (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Compact TXRF system using doubly curved crystal optics

    International Nuclear Information System (INIS)

    Chen, Z.W.

    2000-01-01

    Doubly curved crystal optics can provide large collection solid angle from a small x-ray source but were difficult to be fabricated in the past. The recent innovative doubly curved crystal optic technology provides accurate bending figure of thin crystal and produces high performance doubly curved crystal optics. The high quality doubly curved crystal can increase the intensity of the primary beam significantly for total reflection x-ray fluorescence application based on a low power x-ray source. In this report, toroidal Si(220) crystals are used to focused Cu Kα and Mo Kα x-rays from low power compact x-ray tubes that have maximum power setting at 50 kV and 1 mA. With a slit aperture to control the convergent angle, a fan Cu Kα1 beam with 15 degree x 0.2 degree convergent angles is obtained for TXRF excitation. Similarly, a fan Mo Kα1 beam with 6 degree x 0.1 degree convergent angles is used for high energy excitation. Si wafer based TXRF samples will be prepared and measured using this technique and the experimental data. (author)

  6. Confinement stabilises single crystal vaterite rods.

    OpenAIRE

    Schenk, AS; Albarracin, EJ; Kim, YY; Ihli, J; Meldrum, FC

    2014-01-01

    Single-crystals of vaterite, the least-stable anhydrous polymorph of CaCO3, are rare in biogenic and synthetic systems. We here describe the synthesis of high aspect ratio single crystal vaterite rods under additive-free conditions by precipitating CaCO3 within the cylindrical pores of track-etch membranes.

  7. Reshock and release response of aluminum single crystal

    International Nuclear Information System (INIS)

    Huang, H.; Asay, J. R.

    2007-01-01

    Reshock and release experiments were performed on single crystal aluminum along three orientations and on polycrystalline 1050 aluminum with 50 μm grain size at shock stresses of 13 and 21 GPa to investigate the mechanisms for previously observed quasielastic recompression behavior. Particle velocity profiles obtained during reshocking both single crystals and polycrystalline aluminum from initial shock stresses of 13-21 GPa show similar quasielastic recompression behavior. Quasielastic release response is also observed in all single crystals, but the magnitude of the effect is crystal orientation dependent, with [111] and [110] exhibiting more ideal elastic-plastic release for unloading from the shocked state than for the [100] orientation and polycrystalline aluminum. The quasielastic response of 1050 aluminum is intermediate to that of the [100] and [111] orientations. Comparison of the wave profiles obtained for both unloading and reloading of single crystals and polycrystalline 1050 aluminum from shocked states suggests that the observed quasielastic response of polycrystalline aluminum results from the averaging response of single crystals for shock propagation along different orientations, and that the response of 1050 aluminum with large grain boundaries is not significantly different from the results obtained on single crystal aluminum. The yield strength of the single crystals and 1050 aluminum is found to increase with shock stress, which is consistent with previous results [H. Huang and I. R. Asay, J. Appl. Phys. 98, 033524 (2005)

  8. Growth of dopamine crystals

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Vidya, E-mail: vidya.patil@ruparel.edu; Patki, Mugdha, E-mail: mugdha.patki@ruparel.edu [D. G. Ruparel College, Senapati Bapat Marg, Mahim, Mumbai – 400 016 (India)

    2016-05-06

    Many nonlinear optical (NLO) crystals have been identified as potential candidates in optical and electro-optical devices. Use of NLO organic crystals is expected in photonic applications. Hence organic nonlinear optical materials have been intensely investigated due to their potentially high nonlinearities, and rapid response in electro-optic effect compared to inorganic NLO materials. There are many methods to grow organic crystals such as vapor growth method, melt growth method and solution growth method. Out of these methods, solution growth method is useful in providing constraint free crystal. Single crystals of Dopamine have been grown by evaporating the solvents from aqueous solution. Crystals obtained were of the size of orders of mm. The crystal structure of dopamine was determined using XRD technique. Images of crystals were obtained using FEG SEM Quanta Series under high vacuum and low KV.

  9. Controllable optical bistability in photonic-crystal one-atom laser

    International Nuclear Information System (INIS)

    Guo Xiaoyong; Lue Shuchen

    2009-01-01

    We investigate the property of optical bistability in a photonic-crystal one-atom laser when nonlinear microcavity is present. The physical system consists of a coherently driven two-level light emitter strongly coupled to a high-quality microcavity which is embedded within a photonic crystal and another coherent probing field which has incident into the microcavity. In our case, the microcavity is fabricated by nonlinear material and placed as an impurity in photonic crystal. This study reveals that such a system can exhibit optical bistability. The dependence of threshold value and hysteresis loop on the photonic band gap of the photonic crystal, driving field Rabi frequency and dephasing processes, are studied. Our results clearly illustrate the ability to control optical bistability through suitable photonic-crystal architectures and external coherent driving field, and this study suggests that in a photonic-crystal nonlinear microcavity, the one-atom laser acts as an effective controllable bistable device in the design of all-light digital computing systems in the near future.

  10. Unusual ruby-sapphire transition in alluvial megacrysts, Cenozoic basaltic gem field, New England, New South Wales, Australia

    Science.gov (United States)

    Sutherland, Frederick L.; Graham, Ian T.; Harris, Stephen J.; Coldham, Terry; Powell, William; Belousova, Elena A.; Martin, Laure

    2017-05-01

    Rare ruby crystals appear among prevailing sapphire crystals mined from placers within basaltic areas in the New England gem-field, New South Wales, Australia. New England ruby (NER) has distinctive trace element features compared to those from ruby elsewhere in Australia and indeed most ruby from across the world. The NER suite includes ruby (up to 3370 ppm Cr), pink sapphire (up to 1520 ppm Cr), white sapphire (up to 910 ppm) and violet, mauve, purple, or bluish sapphire (up to 1410 ppm Cr). Some crystals show outward growth banding in this respective colour sequence. All four colour zones are notably high in Ga (up to 310 ppm) and Si (up to 1820 ppm). High Ga and Ga/Mg values are unusual in ruby and its trace element plots (laser ablation-inductively coupled plasma-mass spectrometry) and suggests that magmatic-metasomatic inputs were involved in the NER suite genesis. In situ oxygen isotope analyses (secondary ion mass spectrometry) across the NER suite colour range showed little variation (n = 22; δ18O = 4.4 ± 0.4, 2σ error), and are values typical for corundum associated with ultramafic/mafic rocks. The isolated NER xenocryst suite, corroded by basalt transport and with few internal inclusions, presents a challenge in deciphering its exact origin. Detailed consideration of its high Ga chemistry in relation to the known geology of the surrounding region was used to narrow down potential sources. These include Late Palaeozoic-Triassic fractionated I-type granitoid magmas or Mesozoic-Cenozoic felsic fractionates from basaltic magmas that interacted with early Palaeozoic Cr-bearing ophiolite bodies in the New England Orogen. Other potential sources may lie deeper within lower crust-mantle metamorphic assemblages, but need to match the anomalous high-Ga geochemistry of the New England ruby suite.

  11. Sapphire: a better material for atomization and in situ collection of silver volatile species for atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Musil, Stanislav, E-mail: stanomusil@biomed.cas.cz; Matoušek, Tomáš; Dědina, Jiří

    2015-06-01

    Sapphire is presented as a high temperature and corrosion resistant material of an optical tube of an atomizer for volatile species of Ag generated by the reaction with NaBH{sub 4}. The modular atomizer design was employed which allowed to carry out the measurements in two modes: (i) on-line atomization and (ii) in situ collection (directly in the optical tube) by means of excess of O{sub 2} over H{sub 2} in the carrier gas during the trapping step and vice versa in the volatilization step. In comparison with quartz atomizers, the sapphire tube atomizer provides a significantly increased atomizer lifetime as well as substantially improved repeatability of the Ag in situ collection signals shapes. In situ collection of Ag in the sapphire tube atomizer was highly efficient (> 90%). Limit of detection in the on-line atomization mode and in situ collection mode, respectively, was 1.2 ng ml{sup −1} and 0.15 ng ml{sup −1}. - Highlights: • Sapphire was tested as a new material of an atomizer tube for Ag volatile species. • Two measurement modes were investigated: on-line atomization and in situ collection. • In situ collection of Ag was highly efficient (> 90%) with LOD of 0.15 ng ml{sup −1}. • No devitrification of the sapphire tube observed in the course of several months.

  12. Widely tunable femtosecond solitonic radiation in photonic crystal fiber cladding

    DEFF Research Database (Denmark)

    Peng, J. H.; Sokolov, A. V.; Benabid, F.

    2010-01-01

    We report on a means to generate tunable ultrashort optical pulses. We demonstrate that dispersive waves generated by solitons within the small-core features of a photonic crystal fiber cladding can be used to obtain femtosecond pulses tunable over an octave-wide spectral range. The generation...... process is highly efficient and occurs at the relatively low laser powers available from a simple Ti:sapphire laser oscillator. The described phenomenon is general and will play an important role in other systems where solitons are known to exist....

  13. Single-nanoparticle detection with slot-mode photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cheng; Kita, Shota; Lončar, Marko, E-mail: loncar@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Li, Yihang [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

    2015-06-29

    Optical cavities that are capable for detecting single nanoparticles could lead to great progress in early stage disease diagnostics and the study of biological interactions on the single-molecule level. In particular, photonic crystal (PhC) cavities are excellent platforms for label-free single-nanoparticle detection, owing to their high quality (Q) factors and wavelength-scale modal volumes. Here, we demonstrate the design and fabrication of a high-Q (>10{sup 4}) slot-mode PhC nanobeam cavity, which is able to strongly confine light in the slotted regions. The enhanced light-matter interaction results in an order of magnitude improvement in both refractive index sensitivity (439 nm/RIU) and single-nanoparticle sensitivity compared with conventional dielectric-mode PhC cavities. Detection of single polystyrene nanoparticles with radii of 20 nm and 30 nm is demonstrated in aqueous environments (D{sub 2}O), without additional laser and temperature stabilization techniques.

  14. Growth of single crystals of BaFe12O19 by solid state crystal growth

    Science.gov (United States)

    Fisher, John G.; Sun, Hengyang; Kook, Young-Geun; Kim, Joon-Seong; Le, Phan Gia

    2016-10-01

    Single crystals of BaFe12O19 are grown for the first time by solid state crystal growth. Seed crystals of BaFe12O19 are buried in BaFe12O19+1 wt% BaCO3 powder, which are then pressed into pellets containing the seed crystals. During sintering, single crystals of BaFe12O19 up to ∼130 μm thick in the c-axis direction grow on the seed crystals by consuming grains from the surrounding polycrystalline matrix. Scanning electron microscopy-energy dispersive spectroscopy analysis shows that the single crystal and the surrounding polycrystalline matrix have the same chemical composition. Micro-Raman scattering shows the single crystal to have the BaFe12O19 structure. The optimum growth temperature is found to be 1200 °C. The single crystal growth behavior is explained using the mixed control theory of grain growth.

  15. Silicon photonic crystal all-optical logic gates

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yulan [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Hu, Xiaoyong, E-mail: xiaoyonghu@pku.edu.cn [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Gong, Qihuang, E-mail: qhgong@pku.edu.cn [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China)

    2013-01-03

    All-optical logic gates, including OR, XOR, NOT, XNOR, and NAND gates, are realized theoretically in a two-dimensional silicon photonic crystal using the light beam interference effect. The ingenious photonic crystal waveguide component design, the precisely controlled optical path difference, and the elaborate device configuration ensure the simultaneous realization of five types of logic gate with low-power and a contrast ratio between the logic states of “1” and “0” as high as 20 dB. High power is not necessary for operation of these logic gate devices. This offers a simple and effective approach for the realization of integrated all-optical logic devices.

  16. Growth of large size lithium niobate single crystals of high quality by tilting-mirror-type floating zone method

    Energy Technology Data Exchange (ETDEWEB)

    Sarker, Abdur Razzaque, E-mail: razzaque_ru2000@yahoo.com [Department of Physics, University of Rajshahi (Bangladesh)

    2016-05-15

    Large size high quality LiNbO{sub 3} single crystals were grown successfully by tilting-mirror-type floating zone (TMFZ) technique. The grown crystals were characterized by X-ray diffraction, etch pits density measurement, Impedance analysis, Vibrating sample magnetometry (VSM) and UV-Visible spectrometry. The effect of mirror tilting during growth on the structural, electrical, optical properties and defect density of the LiNbO{sub 3} crystals were investigated. It was found that the defect density in the crystals reduced for tilting the mirror in the TMFZ method. The chemical analysis revealed that the grown crystals were of high quality with uniform composition. The single crystals grown by TMFZ method contains no low-angle grain boundaries, indicating that they can be used for high efficiency optoelectronic devices. (author)

  17. Ga2O3-In2O3 thin films on sapphire substrates: Synthesis and ultraviolet photoconductivity

    Science.gov (United States)

    Muslimov, A. E.; Butashin, A. V.; Kolymagin, A. B.; Nabatov, B. V.; Kanevsky, V. M.

    2017-11-01

    The structure and electrical and optical properties of β-Ga2O3-In2O3 thin films on sapphire substrates with different orientations have been investigated. The samples have been prepared by annealing of gallium-indium metallic films on sapphire substrates in air at different gallium-to-indium ratios in the initial mixture. The photoconductivity of these structures in the solar-blind ultraviolet spectral region has been examined.

  18. Self-templated synthesis of single-crystal and single-domain ferroelectric nanoplates

    KAUST Repository

    Chao, Chunying; Ren, Zhaohui; Zhu, Yihan; Xiao, Zhen; Liu, Zhenya; Xú , Gang; Mai, Jiangquan; Li, Xiang; Shen, Ge; Han, Gaorong

    2012-01-01

    Free-standing single-crystal PbTiO 3 nanoplates (see picture) were synthesized by a facile hydrothermal method. A "self-templated" crystal growth is presumed to lead to the formation of the PbTiO 3 nanoplates, which have ferroelectric single

  19. Origin of the defects-induced ferromagnetism in un-doped ZnO single crystals

    Science.gov (United States)

    Zhan, Peng; Xie, Zheng; Li, Zhengcao; Wang, Weipeng; Zhang, Zhengjun; Li, Zhuoxin; Cheng, Guodong; Zhang, Peng; Wang, Baoyi; Cao, Xingzhong

    2013-02-01

    We clarified, in this Letter, that in un-doped ZnO single crystals after thermal annealing in flowing argon, the defects-induced room-temperature ferromagnetism was originated from the surface defects and specifically, from singly occupied oxygen vacancies denoted as F+, by the optical and electrical properties measurements as well as positron annihilation analysis. In addition, a positive linear relationship was observed between the ferromagnetism and the F+ concentration, which is in support with the above clarification.

  20. Coloration of chromium-doped yttrium aluminum garnet single-crystal fibers using a divalent codopant

    International Nuclear Information System (INIS)

    Tissue, B.M.; Jia, W.; Lu, L.; Yen, W.M.

    1991-01-01

    We have grown single-crystal fibers of Cr:YAG and Cr,Ca:YAG under oxidizing and reducing conditions by the laser-heated-pedestal-growth method. The Cr:YAG crystals were light green due to Cr 3+ in octahedral sites, while the Cr,Ca:YAG crystals were brown. The presence of the divalent codopant was the dominant factor determining the coloration in these single-crystal fibers, while the oxidizing power of the growth atmosphere had little effect on the coloration. The Cr,Ca:YAG had a broad absorption band centered at 1.03 μm and fluoresced from 1.1 to 1.7 μm, with a room-temperature lifetime of 3.5 μs. The presence of both chromium and a divalent codopant were necessary to create the optically-active center which produces the near-infrared emission. Doping with only Ca 2+ created a different coloration with absorption in the blue and ultraviolet. The coloration in the Cr,Ca:YAG is attributed to Cr 4+ and is produced in as-grown crystals without irradiation or annealing, as has been necessary in previous work

  1. All-optical image processing with nonlinear liquid crystals

    Science.gov (United States)

    Hong, Kuan-Lun

    Liquid crystals are fascinating materials because of several advantages such as large optical birefringence, dielectric anisotropic, and easily compatible to most kinds of materials. Compared to the electro-optical properties of liquid crystals widely applied in displays and switching application, transparency through most parts of wavelengths also makes liquid crystals a better candidate for all-optical processing. The fast response time of liquid crystals resulting from multiple nonlinear effects, such as thermal and density effect can even make real-time processing realized. In addition, blue phase liquid crystals with spontaneously self-assembled three dimensional cubic structures attracted academic attention. In my dissertation, I will divide the whole contents into six parts. In Chapter 1, a brief introduction of liquid crystals is presented, including the current progress and the classification of liquid crystals. Anisotropy and laser induced director axis reorientation is presented in Chapter 2. In Chapter 3, I will solve the electrostrictive coupled equation and analyze the laser induced thermal and density effect in both static and dynamic ways. Furthermore, a dynamic simulation of laser induced density fluctuation is proposed by applying finite element method. In Chapter 4, two image processing setups are presented. One is the intensity inversion experiment in which intensity dependent phase modulation is the mechanism. The other is the wavelength conversion experiment in which I can read the invisible image with a visible probe beam. Both experiments are accompanied with simulations to realize the matching between the theories and practical experiment results. In Chapter 5, optical properties of blue phase liquid crystals will be introduced and discussed. The results of grating diffractions and thermal refractive index gradient are presented in this chapter. In addition, fiber arrays imaging and switching with BPLCs will be included in this chapter

  2. A compact, all-optical, THz wave generator based on self-modulation in a slab photonic crystal waveguide with a single sub-nanometer graphene layer.

    Science.gov (United States)

    Asadi, R; Ouyang, Z; Mohammd, M M

    2015-07-14

    We design a compact, all-optical THz wave generator based on self-modulation in a 1-D slab photonic crystal (PhC) waveguide with a single sub-nanometer graphene layer by using enhanced nonlinearity of graphene. It has been shown that at the bandgap edge of higher bands of a 1-D slab PhC, through only one sub-nanometer graphene layer we can obtain a compact, high modulation factor (about 0.98 percent), self-intensity modulator at a high frequency (about 0.6 THz) and low threshold intensity (about 15 MW per square centimeter), and further a compact, all-optical THz wave generator by integrating the self-modulator with a THz photodiode or photonic mixer. Such a THz source is expected to have a relatively high efficiency compared with conventional sources based on optical methods. The proposed THz source can find wide applications in THz science and technology, e.g., in THz imaging, THz sensors and detectors, THz communication systems, and THz optical integrated logic circuits.

  3. Growth and characterization of an organic single crystal: 2-[2-(4-Diethylamino-phenyl)-vinyl]-1-methyl-pyridinium iodide

    Science.gov (United States)

    Senthil, K.; Kalainathan, S.; Ruban Kumar, A.

    Optically transparent crystal of the organic salt DEASI (2-[2-(4-Diethylamino-phenyl)-vinyl]-1-methyl-pyridinium iodide) has been synthesized by using knoevenagel condensation reaction method. The synthesized material has been purified by successfully recrystallization process. Single crystals of DEASI have been grown by slow evaporation technique at room temperature. The solubility of the title material has been determined at different temperature in acetonitrile/methanol mixture. The cell parameters and crystallinity of the title crystal were determined by single crystal XRD. The powder diffraction was carried out to study the reflection plane of the grown crystal and diffraction peaks were indexed. The presence of different functional groups in the crystal was confirmed by Fourier transform infrared (FTIR) analysis. 1H NMR spectrum was recorded to confirm the presence of hydrogen nuclei in the synthesized material. The optical property of the title crystal was studied by UV-Vis-NIR spectroscopic analysis. The melting point and thermal property of DEASI were studied using TGA/DSC technique. The Vicker’s hardness (Hv) was carried out to know the category. The dielectric constant and dielectric loss of the compound decreases with an increase in frequencies. Chemical etching studies showed that the DEASI grows in the two dimensional growth mechanisms. The Kurtz-Perry powder second harmonic generation (SHG) test has done for title crystal.

  4. Growth and characterization of an organic single crystal: 2-[2-(4-diethylamino-phenyl)-vinyl]-1-methyl-pyridinium iodide.

    Science.gov (United States)

    Senthil, K; Kalainathan, S; Ruban Kumar, A

    2014-05-05

    Optically transparent crystal of the organic salt DEASI (2-[2-(4-Diethylamino-phenyl)-vinyl]-1-methyl-pyridinium iodide) has been synthesized by using knoevenagel condensation reaction method. The synthesized material has been purified by successfully recrystallization process. Single crystals of DEASI have been grown by slow evaporation technique at room temperature. The solubility of the title material has been determined at different temperature in acetonitrile/methanol mixture. The cell parameters and crystallinity of the title crystal were determined by single crystal XRD. The powder diffraction was carried out to study the reflection plane of the grown crystal and diffraction peaks were indexed. The presence of different functional groups in the crystal was confirmed by Fourier transform infrared (FTIR) analysis. (1)H NMR spectrum was recorded to confirm the presence of hydrogen nuclei in the synthesized material. The optical property of the title crystal was studied by UV-Vis-NIR spectroscopic analysis. The melting point and thermal property of DEASI were studied using TGA/DSC technique. The Vicker's hardness (Hv) was carried out to know the category. The dielectric constant and dielectric loss of the compound decreases with an increase in frequencies. Chemical etching studies showed that the DEASI grows in the two dimensional growth mechanisms. The Kurtz-Perry powder second harmonic generation (SHG) test has done for title crystal. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Investigation of structural phase transition in strontium titanate single crystal by methods of generation of coherent and incoherent second optical harmonics

    International Nuclear Information System (INIS)

    Mishina, E.D.; Morozov, A.I.; Sigov, A.S.; Sherstyuk, N.Eh.; Aktsipetrov, O.A.; Lemanov, V.V.; Rasing, Th.

    2002-01-01

    The surface phase transition in the SrTiO 3 crystal is studied through the method of the second optical harmonic generation. The peculiarities in the nonlinear-optical response are identified at the temperature of T* = 145 K, which by 40 K exceeds the T c temperature of the structural phase transition in the crystal volume. The phenomenon of the nonlinear critical opalescence, caused by availability of the point defects, is studied. The second harmonic field and critical opalescence intensity are calculated on the basis of the phenomenological model of the nonlinear-optical processes with application of the Landau phase transition theory [ru

  6. Inkjet printing of single-crystal films.

    Science.gov (United States)

    Minemawari, Hiromi; Yamada, Toshikazu; Matsui, Hiroyuki; Tsutsumi, Jun'ya; Haas, Simon; Chiba, Ryosuke; Kumai, Reiji; Hasegawa, Tatsuo

    2011-07-13

    The use of single crystals has been fundamental to the development of semiconductor microelectronics and solid-state science. Whether based on inorganic or organic materials, the devices that show the highest performance rely on single-crystal interfaces, with their nearly perfect translational symmetry and exceptionally high chemical purity. Attention has recently been focused on developing simple ways of producing electronic devices by means of printing technologies. 'Printed electronics' is being explored for the manufacture of large-area and flexible electronic devices by the patterned application of functional inks containing soluble or dispersed semiconducting materials. However, because of the strong self-organizing tendency of the deposited materials, the production of semiconducting thin films of high crystallinity (indispensable for realizing high carrier mobility) may be incompatible with conventional printing processes. Here we develop a method that combines the technique of antisolvent crystallization with inkjet printing to produce organic semiconducting thin films of high crystallinity. Specifically, we show that mixing fine droplets of an antisolvent and a solution of an active semiconducting component within a confined area on an amorphous substrate can trigger the controlled formation of exceptionally uniform single-crystal or polycrystalline thin films that grow at the liquid-air interfaces. Using this approach, we have printed single crystals of the organic semiconductor 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C(8)-BTBT) (ref. 15), yielding thin-film transistors with average carrier mobilities as high as 16.4 cm(2) V(-1) s(-1). This printing technique constitutes a major step towards the use of high-performance single-crystal semiconductor devices for large-area and flexible electronics applications.

  7. Magneto-optics observation of spontaneous domain structure in ferromagnetic La0.78Ca0.22MnO3 single crystal

    International Nuclear Information System (INIS)

    Jung, G; Indenbom, M; Markovich, V; Beek, C J van der; Mogilyansky, D; Mukovskii, Ya M

    2004-01-01

    Spontaneous ferromagnetic domains in lightly Ca-doped La 1-x Ca x MnO 3 single crystals have been visualized and investigated by means of the magneto-optical technique. In marked difference to the magnetic contrast structures associated with magneto-crystalline anisotropy, which appear only in applied magnetic field, spontaneous ferromagnetic domains show up at low temperatures below the Curie temperature in zero applied field and are characterized by oppositely oriented spontaneous magnetization in adjacent domains. Ferromagnetic domains seen in zero field cooled samples take the form of almost periodic, corrugated stripe-like structures. Application of even a very weak magnetic field during cooling through the magnetic ordering transition changes the stripe domain structures into a bubble domain system

  8. High Power 1443.5 nm Laser with Nd:YAG Single Crystal Fiber

    Directory of Open Access Journals (Sweden)

    Han Rao

    2017-07-01

    Full Text Available A high-power eye-safe 1443.5 nm laser was demonstrated with an Nd:YAG single crystal fiber (SCF as the gain medium. For continuous wave (CW operation, a maximum output power of 13.3 W was obtained under an absorbed pump power of 95.0 W, corresponding to an optical-to-optical conversion efficiency of 14.0%. For acousto-optically (AO Q-switched regime, an output power of 1.95 W was obtained at a pulse repetition frequency (PRF of 10 kHz. The pulse duration was 69.5 ns. The pulse energy and peak power were calculated to be 195 µJ and 2.81 kW, respectively.

  9. Optical Studies on Sol-Gel Derived Lead Chloride Crystals

    OpenAIRE

    Rejeena, I; Lillibai, B; Nithyaja, B; Nampoori, P.N V; Radhakrishnan, P

    2013-01-01

    Optical characterization of lead chloride crystals prepared by sol-gel method is reported. The relevant sol-gel technique is used for the preparation of PbCl2 samples with five different types. In this paper, we report the absorption and fluorescence behaviour of pure, UV& IR irradiated and electric & magnetic field applied lead chloride crystal samples in solution phase at two different concentrations. Optical bandgap and emission studies of these crystals are also done.

  10. Optical properties of tungsten disulfide single crystals doped with gold

    International Nuclear Information System (INIS)

    Dumcenco, D.O.; Hsu, H.P.; Huang, Y.S.; Liang, C.H.; Tiong, K.K.; Du, C.H.

    2008-01-01

    Single crystals of WS 2 doped with gold have been grown by the chemical vapour transport method using iodine as a transporting agent. X-ray diffraction (XRD) pattern analysis revealed presence of mixed three-layer rhombohedral (3R) and two-layer hexagonal (2H) polytypes for the doped crystals while the undoped one shows only 2H form. Hall measurements indicate that the samples are p-type in nature. The doping effects of the materials are characterized by surface photovoltage (SPV), photoconductivity (PC) and piezoreflectance (PzR) measurements. Room temperature SPV and PC spectra reveal a feature located at ∼60 meV below the A exciton and has been tentatively assigned to be an impurity level caused by Au dopant. Excitonic transition energies of the A, B, d and C excitons detected in PzR spectra show red shift due to the presence of a small amount of Au and the broadening parameters of the excitonic transition features increase due to impurity scattering. The values of the parameters that describe the electron (exciton)-phonon interaction of excitonic transitions of A-B are about two times larger than that of d-C excitonic pairs. The possible assignments of the different origins of A-B and d-C excitonic pairs have been discussed

  11. Periodic reversal of magneto-optic Faraday rotation on uniaxial birefringence crystal with ultrathin magnetic films

    Directory of Open Access Journals (Sweden)

    C. W. Su

    2013-07-01

    Full Text Available An experimental approach of inclined incidence magneto-optic Faraday effect observed in the polar plane is applied. Three samples containing ferromagnetic cobalt ultrathin films on a semiconductor zinc oxide (0001 single crystal substrate with in-plane and out-of-plane anisotropy are evaluated. Through the fine adjustment of crossed polarizers in the magneto-optic effect measurement completely recorded the detail optical and magneto-optical responses from the birefringent crystal substrate and the magnetic film, especially for the signal induced from the substrate with uniaxial optical axis. The angle dependency of interference phenomena periodically from the optical and magneto-optical responses is attributed to the birefringence even in the absence of a magnetic field. The new type of observation finds that the transmission Faraday intensity in the oblique incidence includes a combination of polarization rotations, which results from optical compensation from the substrate and magneto-optical Faraday effects from the film. The samples grown at different rates and examined by this method exhibit magnetic structure discriminations. This result can be applied in the advanced polarized-light technologies to enhance the spatial resolution of magnetic surfaces with microstructural information under various magnetic field direction.

  12. Controlled growth of filamentary crystals and fabrication of single-crystal whisker probes

    International Nuclear Information System (INIS)

    Givargizov, E. I.

    2006-01-01

    The growth of filamentary crystals (whiskers) on a single-crystal substrate through the vapour-liquid-solid mechanism is described. The possibility of fabricating oriented systems of whiskers on the basis of this mechanism of crystal growth is noted. A phenomenon that is important for nanotechnology is noted: the existence of a critical diameter of whiskers, below which they are not formed. The phenomenon of radial periodic instability, which is characteristic of nanowhiskers, is described and the ways of its elimination are shown. The possibility of transforming whiskers into single-crystal tips and the growth of crystalline diamond particles at their apices are noted as important for practice. Possible applications of systems of whiskers and tips are described briefly. Particular attention is paid to the latest direction in whisker technology-fabrication of single-crystal whisker probes for atomic force microscopy

  13. Radhard optical patchcords and packaging for satellites using liquid crystal polymers

    Science.gov (United States)

    O'Riorden, S.; Mahapatra, A.

    2017-11-01

    There are many advantages to employing fiber optics for high capacity satellite communication. However, optical cables can be susceptible to high radiation, temperature extremes and vacuum environment. Any hardware used in these systems must be rugged, durable and immune to the detrimental effects of the aforementioned conditions. Standard COTS optical fiber will darken when exposed to high levels of radiation limiting the effectiveness of the communications system. Of particular concern to satellites in GEO are energetic electrons, bursts of heavy particles due to solar storms which can cause total dose and single event effects (SEE). Conventional fiber optic cables have several issues performing in high radiation environments. Linden has patented and developed a novel cable using an extruded layer of Liquid Crystal Polymer (LCP) applied to commercially available fiber. Total dose effects are minimized by shielding with Liquid Crystal Polymer jacketing. It is a simple, inexpensive way to increase the radiation shielding and mechanical performance of cables in satellites while concomitantly providing hermeticity and thus increased fatigue factor for optical glass. • LCPs exposed to 5000 Mrad dose of gamma rays retain in excess of 90% of their mechanical properties. • LCPs exposed to 1 Mrad radiation dose with energetic protons retain almost 100% of their mechanical strength. Tensile modulus increases with exposure to the radiation. • Weight for weight the proton absorbing power of LCP is 25% better than that of aluminum. We will present experimental data on radhard optical patchcords.

  14. Crystal structure and magnetic susceptibility of UOSe single crystals

    International Nuclear Information System (INIS)

    Kaczorowski, D.; Muenster Univ.; Poettgen, R.; Jeitschko, W.; Gajek, Z.; Zygmunt, A.

    1993-01-01

    The crystal structure and magnetic susceptibility behaviour of UOSe single crystals have been studied. UOSe crystalizes in the tetragonal PbFC1-type structure (space group P4/nmm) with the lattice parameters: a = 390.38(5) pm and c = 698.05(9) pm. It orders antiferromagnetically at T N =100±2 K and exhibits a very strong anisotropy in the susceptibility vs temperature variation. The magnetic and thermodynamic properties of UOSe are successfully interpreted in the framework of a perturbative ab initio crystal field approach. (Author)

  15. Crystal structure and magnetic susceptibility of UOSe single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kaczorowski, D. (Polish Academy of Sciences, Wroclaw (Poland). Inst. for Low Temperature and Structure Research Muenster Univ. (Germany). Anorganisch-Chemisches Inst.); Poettgen, R.; Jeitschko, W. (Muenster Univ. (Germany). Anorganisch-Chemisches Inst.); Gajek, Z.; Zygmunt, A. (Polish Academy of Sciences, Wroclaw (Poland). Inst. for Low Temperature and Structure Research)

    1993-01-01

    The crystal structure and magnetic susceptibility behaviour of UOSe single crystals have been studied. UOSe crystalizes in the tetragonal PbFC1-type structure (space group P4/nmm) with the lattice parameters: a = 390.38(5) pm and c = 698.05(9) pm. It orders antiferromagnetically at T[sub N]=100[+-]2 K and exhibits a very strong anisotropy in the susceptibility vs temperature variation. The magnetic and thermodynamic properties of UOSe are successfully interpreted in the framework of a perturbative ab initio crystal field approach. (Author).

  16. Optical properties and radiation response of Ce3+-doped GdScO3 crystals

    International Nuclear Information System (INIS)

    Yamaji, Akihiro; Fujimoto, Yutaka; Futami, Yoshisuke; Yokota, Yuui; Kurosawa, Shunsuke; Kochurikhin, Vladimir; Yanagida, Takayuki; Yoshikawa, Akira

    2012-01-01

    10%-Ce doped GdScO 3 perovskite type single crystal was grown by the Czochralski process. The Ce concentration in the crystal was measured. No impurity phases were observed by powder X-ray diffraction analysis. We evaluated the optical and radiation properties of the grown crystal. Ce:GdScO 3 crystal showed photo- and radio-luminescence peaks due to Ce 3+ of 5d-4f transition and colour centre. The photoluminescence decay time was sub-ns order. The relative light yield under 5.5 MeV alpha-ray excitation was calculated to be approximately 9% of BGO. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Photoluminescence Polarization Anisotropy in a Single Heterostructured III-V Nanowire with Mixed Crystal Phases

    International Nuclear Information System (INIS)

    Moses, A. F.; Hoang, T. B.; Ahtapodov, L.; Dheeraj, D. L.; Fimland, B. O.; Weman, H.; Helvoort, A. T. J. van

    2011-01-01

    Low temperature (10 K) micro-photoluminescence (μ-PL) of single GaAs/AlGaAs core-shell nanowires with single GaAsSb inserts were measured. The PL emission from the zinc blende GaAsSb insert is strongly polarized along the nanowire axis while the PL emission from the wurtzite GaAs nanowire is perpendiculary polarized to the nanowire axis. The result indicates that the crystal phase, through the optical selection rules, has significant effect on the polarization of the PL from NWs besides the dielectric mismatch. The analysis of the PL results based on the electronic structure of these nanowires supports the correlation between the crystal phase and the PL emission.

  18. Comparative study of optical and scintillation properties of YVO4, (Lu0.5Y0.5)VO4, and LuVO4 single crystals

    International Nuclear Information System (INIS)

    Fujimoto, Yutaka; Yanagida, Takayuki; Yokota, Yuui; Chani, Valery; Kochurikhin, Vladimir V.; Yoshikawa, Akira

    2011-01-01

    Optical and scintillation properties of YVO 4 , (Lu 0.5 Y 0.5 )VO 4 , and LuVO 4 single crystals grown by the Czochralski (CZ) method with RF heating system are compared. All vanadate crystals show high transmittance (∼80%) in the 400-900 nm wavelength range. In both photo- and radio-luminescence spectra, intense peak around 400-500 nm, which was ascribed to the transition from triplet state of VO 4 3- , was clearly observed. The main decay time component was about 38 μs (YVO 4 ), 18 μs ((Lu 0.5 Y 0.5 )VO 4 ), and 17 μs (LuVO 4 ) under 340 nm excitation. The scintillation light yields of YVO 4 , (Lu 0.5 Y 0.5 )VO 4 , and LuVO 4 crystals (obtained from the 137 Cs excited pulse height spectra) were evaluated to be about 11,200, 10,700, and 10,300 ph/MeV, respectively.

  19. Solid state synthesis, crystal growth and optical properties of urea and p-chloronitrobenzene solid solution

    Energy Technology Data Exchange (ETDEWEB)

    Rai, R.N., E-mail: rn_rai@yahoo.co.in [Department of Chemistry, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005 (India); Kant, Shiva; Reddi, R.S.B. [Department of Chemistry, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005 (India); Ganesamoorthy, S. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamilnadu (India); Gupta, P.K. [Laser Materials Development & Devices Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

    2016-01-15

    Urea is an attractive material for frequency conversion of high power lasers to UV (for wavelength down to 190 nm), but its usage is hindered due to its hygroscopic nature, though there is no alternative organic NLO crystal which could be transparent up to 190 nm. The hygroscopic character of urea has been modified by making the solid solution (UCNB) of urea (U) and p-chloronitrobenzene (CNB). The formation of the solid solution of CNB in U is explained on the basis of phase diagram, powder XRD, FTIR, elemental analysis and single crystal XRD studies. The solubility of U, CNB and UCNB in ethanol solution is evaluated at different temperatures. Transparent single crystals of UCNB are grown from its saturated solution in ethanol. Optical properties e.g., second harmonic generation (SHG), refractive index and the band gap for UCNB crystal were measured and their values were compared with the parent compounds. Besides modification in hygroscopic nature, UCNB has also shown the higher SHG signal and mechanical hardness in comparison to urea crystal. - Highlights: • The hygroscopic character of urea was modified by making the solid solution • Solid solution formation is support by elemental, powder- and single crystal XRD • Crystal of solid solution has higher SHG signal and mechanical stability. • Refractive index and band gap of solid solution crystal have determined.

  20. Ultraviolet laser crystallized ZnO:Al films on sapphire with high Hall mobility for simultaneous enhancement of conductivity and transparency

    International Nuclear Information System (INIS)

    Nian, Qiong; Zhang, Martin Y.; Schwartz, Bradley D.; Cheng, Gary J.

    2014-01-01

    One of the most challenging issues in transparent conductive oxides (TCOs) is to improve their conductivity without compromising transparency. High conductivity in TCO films often comes from a high carrier concentration, which is detrimental to transparency due to free carrier absorption. Here we show that UV laser crystallization (UVLC) of aluminum-doped ZnO (AZO) films prepared by pulsed laser deposition on sapphire results in much higher Hall mobility, allowing relaxation of the constraints of the conductivity/transparency trade-off. X-ray diffraction patterns and morphological characterizations show grain growth and crystallinity enhancement during UVLC, resulting in less film internal imperfections. Optoelectronic measurements show that UVLC dramatically improves the electron mobility, while the carrier concentration decreases which in turn simultaneously increases conductivity and transparency. AZO films under optimized UVLC achieve the highest electron mobility of 79 cm 2 /V s at a low carrier concentration of 7.9 × 10 +19  cm −3 . This is realized by a laser crystallization induced decrease of both grain boundary density and electron trap density at grain boundaries. The infrared (IR) to mid-IR range transmittance spectrum shows UVLC significantly enhances the AZO film transparency without compromising conductivity.

  1. High quality single crystal Ge nano-membranes for opto-electronic integrated circuitry

    Energy Technology Data Exchange (ETDEWEB)

    Shah, V. A., E-mail: vishal.shah@warwick.ac.uk; Gammon, P. M. [Department of Engineering, The University of Warwick, Coventry CV4 7AL (United Kingdom); Department of Physics, The University of Warwick, Coventry CV4 7AL (United Kingdom); Rhead, S. D.; Halpin, J. E.; Trushkevych, O.; Wilson, N. R.; Myronov, M.; Edwards, R. S.; Patchett, D. H.; Allred, P. S.; Prest, M. J.; Whall, T. E.; Parker, E. H. C.; Leadley, D. R. [Department of Physics, The University of Warwick, Coventry CV4 7AL (United Kingdom); Chávez-Ángel, E. [ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona) (Spain); Department of Physics, UAB, 08193 Bellaterra (Barcelona) (Spain); Shchepetov, A.; Prunnila, M. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo (Finland); Kachkanov, V.; Dolbnya, I. P. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Reparaz, J. S. [ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona) (Spain); and others

    2014-04-14

    A thin, flat, and single crystal germanium membrane would be an ideal platform on which to mount sensors or integrate photonic and electronic devices, using standard silicon processing technology. We present a fabrication technique compatible with integrated-circuit wafer scale processing to produce membranes of thickness between 60 nm and 800 nm, with large areas of up to 3.5 mm{sup 2}. We show how the optical properties change with thickness, including appearance of Fabry-Pérot type interference in thin membranes. The membranes have low Q-factors, which allow the platforms to counteract distortion during agitation and movement. Finally, we report on the physical characteristics showing sub-nm roughness and a homogenous strain profile throughout the freestanding layer, making the single crystal Ge membrane an excellent platform for further epitaxial growth or deposition of materials.

  2. High quality single crystal Ge nano-membranes for opto-electronic integrated circuitry

    International Nuclear Information System (INIS)

    Shah, V. A.; Gammon, P. M.; Rhead, S. D.; Halpin, J. E.; Trushkevych, O.; Wilson, N. R.; Myronov, M.; Edwards, R. S.; Patchett, D. H.; Allred, P. S.; Prest, M. J.; Whall, T. E.; Parker, E. H. C.; Leadley, D. R.; Chávez-Ángel, E.; Shchepetov, A.; Prunnila, M.; Kachkanov, V.; Dolbnya, I. P.; Reparaz, J. S.

    2014-01-01

    A thin, flat, and single crystal germanium membrane would be an ideal platform on which to mount sensors or integrate photonic and electronic devices, using standard silicon processing technology. We present a fabrication technique compatible with integrated-circuit wafer scale processing to produce membranes of thickness between 60 nm and 800 nm, with large areas of up to 3.5 mm 2 . We show how the optical properties change with thickness, including appearance of Fabry-Pérot type interference in thin membranes. The membranes have low Q-factors, which allow the platforms to counteract distortion during agitation and movement. Finally, we report on the physical characteristics showing sub-nm roughness and a homogenous strain profile throughout the freestanding layer, making the single crystal Ge membrane an excellent platform for further epitaxial growth or deposition of materials

  3. NONLINEAR OPTICAL MOLECULAR CRYSTAL BASED ON 2,6-DIAMINOPYRIDINE: SYNTHESIS AND CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    I. M. Pavlovetc

    2014-05-01

    Full Text Available The paper deals with investigation of a new nonlinear optical material based on nonlinear optical chromophore (4-Nitrophenol and aminopyridine (2,6-Diaminopyridine. Calculation results are presented for molecular packing in the crystalline compound, based on the given components. According to these results the finite material must have a noncentrosymmetric lattice, which determines the presence of the second order nonlinear optical response. Investigations carried out in this work confirm these calculations. Results of experiments are given describing the co-crystallization of these components and the following re-crystallization of the obtained material. In order to get a monocrystal form, the optimal conditions for the synthesis of molecular crystals based on these components are determined. Sufficiently large homogeneous crystals are obtained, that gave the possibility to record their spectra in the visible and near infrared parts of the spectrum, to determine their nonlinear optical properties and the level of homogeneity. Their optical (optical transmission and optical laser damage threshold and nonlinear optical properties are presented. For observation and measurement of the nonlinear optical properties an installation was built which implements the comparative method for measurements of nonlinear optical properties. A potassium titanyl oxide phosphate crystal was used as a sample for comparison. Results are given for the conversion efficiency of the primary laser radiation in the second optical harmonic relative to the signal obtained on the potassium titanyl oxide phosphate crystal. Obtained results show that the molecular co-crystal based on 2,6-Diaminopyridine is a promising nonlinear optical material for generating the second optical harmonic on the Nd: YAG laser (532 nm.

  4. Micromechanical properties of C70 single crystals in the temperature range 77-350 K

    International Nuclear Information System (INIS)

    Lubenets, S.V.; Natsik, V.D.; Fomenko, L.S.; Rusakova, A.V.; Natsik, V.D.; Osip'yan, Yu.A.; Orlov, V.I.; Sidorov, N.S.; Izotov, A.N.

    2012-01-01

    Hexagonal single crystals of C 70 up to a size down to 1-2 mm were grown which allowed for the first time to investigate their low-temperature mechanical properties. Morphology, microplasticity anisotropy and the temperature dependence of Vickers microhardness HV (T) of the C 70 crystals in the temperature range 77-350 K involving all known phase transitions have been studied with the aid of optical microscopy and microindentation. The association of the features of HV (T) dependence with orientation phase transformations has been analyzed. It is suggested that anisotropy of microplasticity in the C 70 crystals correlates with the active slip systems.

  5. Crystal growth, vibrational, optical, thermal and theoretical studies of a nonlinear optical material: 2-Methyl 3,5-dinitrobenzoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Sangeetha, K. [Department of Physics, Sri Sarada College for Women, Salem-16 (India); Guru Prasad, L. [Department of Science & Humanities, M. Kumarasamy College of Engineering, Karur (India); Mathammal, R. [Department of Physics, Sri Sarada College for Women, Salem-16 (India)

    2016-11-15

    Single crystals of 2-methyl 3,5-dinitro benzoic acid with reasonable size have been grown by slow evaporation solution growth method using ethanol as solvent. Quantum chemical calculation of 2-methyl 3,5-Dinitro benzoic acid was carried out by using DFT/B3LYP/6-31+G(d,p) method. The powder X-ray diffraction pattern was recorded and indexed. Both the experimental and theoretical vibrational spectrum validates the presence of functional groups. Polarizability, first order hyperpolarizability and the electric dipole moment values have been computed theoretically. The {sup 1}H and {sup 13}C NMR chemical shift of the molecule was calculated and compared with experimental results. TG/DSC analysis has been employed to understand the thermal and physio-chemical stability of the title compound. Frequency conversion property of the crystal was tested by Kurtz and Perry method. Optical absorption behavior of the grown crystal was examined by recording the optical spectrum and band gap energy was also estimated. The calculated HOMO and LUMO energy shows the charge transfer nature of the molecule.

  6. Synthesis and single crystal growth of perovskite semiconductor CsPbBr3

    Science.gov (United States)

    Zhang, Mingzhi; Zheng, Zhiping; Fu, Qiuyun; Chen, Zheng; He, Jianle; Zhang, Sen; Chen, Cheng; Luo, Wei

    2018-02-01

    As a typical representative of all-inorganic lead halide perovskites, cesium lead bromine (CsPbBr3) has attracted significant attention in recent years. The direct band gap semiconductor CsPbBr3 has a wide band gap of 2.25 eV and high average atomic number (Cs: 55, Pb: 82 and Br: 35), which meet most of the requirements for detection of X- and γ-ray radiation, such as high attenuation, high resistivity, and significant photoconductivity response. However, the growth of large volume CsPbBr3 single crystals remains a challenge. In this paper, the synthesis of CsPbBr3 polycrystalline powders by a chemical co-precipitation method was investigated and the optimum synthesis conditions were obtained. A large CsPbBr3 single crystal of 8 mm diameter and 60 mm length was obtained by a creative electronic dynamic gradient (EDG) method. X-ray diffraction (XRD) patterns and X-ray rocking curve showed that the CsPbBr3 crystal preferentially oriented in the (1 1 0) direction and had a low dislocation density and small residual stress in the crystal. The IR and UV-Vis transmittance and temperature-dependent photoluminescence (PL) spectra showed the crystal had a good basic optical performance. The almost linear current-voltage (I-V) curves implied good ohmic contact between the electrodes and crystal surfaces. The resistivity of the crystal was calculated 109-1010 Ω cm. The above results showed that the quality of the obtained crystal had met the demand of optoelectronic applications.

  7. Luminescence spectroscopy of Rb2KTiOF5 oxyfluoride single crystals

    Science.gov (United States)

    Kozlov, A. V.; Pustovarov, V. A.; Sarychev, M. N.; Isaenko, L. I.

    2017-09-01

    Spectra of photoluminescence (PL) and X-ray excited luminescence (XRL) in region of 1.5-5.5 eV, PL excitation spectra using synchrotron radiation (3.7-22 eV), time-resolved impulse cathode-luminescence (ICL) spectra, the temperature depending of the XRL, decay kinetics as well as thermoluminescence curves were measured for single crystals Rb2KTiOF5, a promising nonlinear optical material. Single crystals are transparent in microwave, visible and near UV range, inter-band transition energy is Eg = 4.2 eV. Crystalline structure has two disordered mixed position O/F, phase transition in the region of 215 K. All the obtained results indicate that in luminescence spectra nonelementary band 2.2 eV is connected to the emission of self-trapped excitons. Nonelementary band 2.2 eV associated with the presence local distortion in the octahedron TiOF5. It is observed that at interband excitation in VUV region at energies more than 3.5 Eg the effect of multiplication of electronic excitations appears. That determines the high output of XRL and ICL. Luminescence methods of quality control of grown crystals are proposed.

  8. Distributed Feedback Laser Based on Single Crystal Perovskite

    Science.gov (United States)

    Sun, Shang; Xiao, Shumin; Song, Qinghai

    2017-06-01

    We demonstrate a single crystal perovskite based, with grating-structured photoresist on top, highly polarized distributed feedback laser. A lower laser threshold than the Fabry-Perot mode lasers from the same single crystal CH3NH3PbBr3 microplate was obtained. Single crystal CH3NH3PbBr3 microplates was synthesized with one-step solution processed precipitation method. Once the photoresist on top of the microplate was patterned with electron beam, the device was realized. This one-step fabrication process utilized the advantage of single crystal to the greatest extend. The ultra-low defect density in single crystalline microplate offer an opportunity for lower threshold lasing action compare with poly-crystal perovskite films. In the experiment, the lasing action based on the distributed feedback grating design was found with lower threshold and higher intensity than the Fabry-Perot mode lasers supported by the flat facets of the same microplate.

  9. Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field

    Directory of Open Access Journals (Sweden)

    Amanda García-García

    2016-06-01

    Full Text Available Single-wall carbon nanotubes (SWCNT are anisotropic nanoparticles that can cause modifications in the electrical and electro-optical properties of liquid crystals. The control of the SWCNT concentration, distribution and reorientation in such self-organized fluids allows for the possibility of tuning the liquid crystal properties. The alignment and reorientation of CNTs are studied in a system where the liquid crystal orientation effect has been isolated. Complementary studies including Raman spectroscopy, microscopic inspection and impedance studies were carried out. The results reveal an ordered reorientation of the CNTs induced by an electric field, which does not alter the orientation of the liquid crystal molecules. Moreover, impedance spectroscopy suggests a nonnegligible anchoring force between the CNTs and the liquid crystal molecules.

  10. Single crystals of the anisotropic Kagome staircase compounds Ni3V2O8 and Co3V2O8

    OpenAIRE

    Balakrishnan, G.; Petrenko, O. A.; Lees, M. R.; Paul, D. McK.

    2004-01-01

    Compounds with a Kagome type lattice are known to exhibit magnetic frustration. Large single crystals of two compounds Ni3V2O8 and Co3V2O8, which are variants of a Kagome net lattice, have been grown successfully by the floating zone technique using an optical image furnace. The single crystals are of high quality and exhibit intriguing magnetic properties.

  11. Photoluminescent properties of single crystal diamond microneedles

    Science.gov (United States)

    Malykhin, Sergey A.; Ismagilov, Rinat R.; Tuyakova, Feruza T.; Obraztsova, Ekaterina A.; Fedotov, Pavel V.; Ermakova, Anna; Siyushev, Petr; Katamadze, Konstantin G.; Jelezko, Fedor; Rakovich, Yury P.; Obraztsov, Alexander N.

    2018-01-01

    Single crystal needle-like diamonds shaped as rectangular pyramids were produced by combination of chemical vapor deposition and selective oxidation with dimensions and geometrical characteristics depending on the deposition process parameters. Photoluminescence spectra and their dependencies on wavelength of excitation radiation reveal presence of nitrogen- and silicon-vacancy color centers in the diamond crystallites. Photoluminescence spectra, intensity mapping, and fluorescence lifetime imaging microscopy indicate that silicon-vacancy centers are concentrated at the crystallites apex while nitrogen-vacancy centers are distributed over the whole crystallite. Dependence of the photoluminescence on excitation radiation intensity demonstrates saturation and allows estimation of the color centers density. The combination of structural parameters, geometry and photoluminescent characteristics are prospective for advantageous applications of these diamond crystallites in quantum information processing and optical sensing.

  12. Thermal gradient migration of brine inclusions in synthetic alkali halide single crystals

    International Nuclear Information System (INIS)

    Olander, D.R.; Machiels, A.J.; Balooch, M.; Yagnik, S.K.

    1982-01-01

    An apparatus consisting of an optical microscope with a hot stage attachment capable of simultaneously nonuniformly heating and mechanically loading small single crystals of salt was used to measure the velocities of all-liquid inclusions NaC1 and KC1 specimens under various conditions of temperature, temperature gradient, and uniaxial stress. The rate-controlling elementary step in the migration of the inclusions was found to be associated with interfacial processes, probably dissolution of the hot face. Dislocations are required for this step to take place. The small number of dislocation intersections with small inclusions in nearly perfect crystals causes substantial variations in the velocity, a sensitivity of the velocity to mechanical loading of the crystal, and a velocity which varies approximately as the second power of the temperature gradient

  13. Synthesis, growth, structural, optical and thermal properties of a new organic nonlinear optical crystal: 2-amino 5-chloropyridinium-L-tartarate

    Science.gov (United States)

    Jayanalina, T.; Rajarajan, G.; Boopathi, K.; Sreevani, K.

    2015-09-01

    A new organic nonlinear optical crystal 2-amino-5-chloropyridinium-L-tartarate [2A5CPLTA] has been synthesized and the crystals were grown by slow evaporation solution technique at room temperature using methanol as solvent. The crystal structure of the title compound has been determined by the single crystal X-ray diffraction study and it belongs to the monoclinic system with noncentrosymmetric space group P21. The presence of functional groups was ascertained by Fourier transform infrared analysis. The transmittance and lower cut off of the grown crystal was ascertained by the UV-vis-NIR spectroscopy. Thermal studies reveled that 2A5CPLTA crystal is thermally stable up to 144 °C. The dielectric measurements of the grown crystal were carried out with different frequencies and temperatures. Vickers micro hardness measurement was carried out to study the mechanical behavior of the grown crystal. The second harmonic generation of the title crystal was confirmed by the Kurtz-Perry powder test employing the Nd: YAG laser as the source.

  14. Band structure and optical properties of diglycine nitrate crystal

    International Nuclear Information System (INIS)

    Andriyevsky, Bohdan; Ciepluch-Trojanek, Wioleta; Romanyuk, Mykola; Patryn, Aleksy; Jaskolski, Marcin

    2005-01-01

    Experimental and theoretical investigations of the electron energy characteristics and optical spectra for diglycine nitrate crystal (DGN) (NH 2 CH 2 COOH) 2 .HNO 3 , in the paraelectric phase (T=295K) are presented. Spectral dispersion of light reflection R(E) have been measured in the range of 3-22eV and the optical functions n(E) and k(E) have been calculated using Kramers-Kronig relations. First principal calculations of the electron energy characteristic and optical spectra of DGN crystal have been performed in the frame of density functional theory using CASTEP code (CAmbridge Serial Total Energy Package). Optical transitions forming the low-energy edge of fundamental absorption are associated with the nitrate groups NO 3 . Peculiarities of the band structure and DOS projected onto glycine and NO 3 groups confirm the molecular character of DGN crystal

  15. Infiltration liquid crystal in microstructured polymer optical fibers

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Wei, Lei; Bang, Ole

    2009-01-01

    7 is then infiltrated into about 6 cm of the length of mPOF by using capillary forces with the duration of 45 minutes. The transmission spectrum is measured by an optical spectrum analyzer with 1 nm resolution, and normalized to that of the unfilled fiber as shown by the solid line. The difference......POF is butt-coupled to a conventional single mode fiber (SMF) with the broadband light from a supercontinuum source. It is clear to see the colour of the guided modes is red, since some wavelengths are attenuated by the material loss of PMMA in visible region. A positive dielectric anisotropy liquid crystal E...

  16. Structural, mechanical and light yield characterisation of heat treated LYSO:Ce single crystals for medical imaging applications

    Energy Technology Data Exchange (ETDEWEB)

    Mengucci, P., E-mail: p.mengucci@univpm.it [Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy); André, G. [Laboratoire Léon Brillouin, CEA-CNRS, CE-Saclay, 91191 Gif sur Yvette cedex (France); Auffray, E. [Department PH-CMX CERN, Route de Meyrin, 1211 Geneva 23 (Switzerland); Barucca, G. [Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy); Cecchi, C. [Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, 06123 Perugia (Italy); Chipaux, R. [CEA DSM/IRFU/SEDI, CE-Saclay, 91191 Gif sur Yvette cedex (France); Cousson, A. [Laboratoire Léon Brillouin, CEA-CNRS, CE-Saclay, 91191 Gif sur Yvette cedex (France); Davì, F. [Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy); Di Vara, N. [Department PH-CMX CERN, Route de Meyrin, 1211 Geneva 23 (Switzerland); Rinaldi, D.; Santecchia, E. [Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy)

    2015-06-11

    Five single crystals of cerium-doped lutetium yttrium oxyorthosilicate (LYSO:Ce) grown by the Czochralski method were submitted to structural characterisation by X-ray (XRD) and neutron (ND) diffraction, scanning (SEM) and transmission (TEM) electron microscopy and energy dispersive microanalysis (EDS). The Ultimate Tensile Strength (UTS), the Young Modulus (YM) and the Light Yield (LY) of the samples were also measured in order to correlate the mechanical and the optical behaviour of the crystals with the characteristics of their microstructure. Two of the samples analysed were also heat treated at 300 °C for 10 h to evidence possible variations induced by the temperature in the optical and mechanical response of the crystals. Results showed that the mean compositional variations evidenced by the structural analyses do not affect the mechanical and optical behaviour of the samples. On the contrary, the thermal treatment could induce the formation of coherent spherical particles (size 10 to 15 nm), not uniformly distributed inside the sample, that strongly reduce the UTS and YM values, but it does not affect the optical response of the crystal. This latter result was attributed to the low value of the heating temperature (300 °C) that is not sufficiently high to induce annealing of the oxygen vacancies traps that are responsible of the deterioration of the scintillation properties of the LYSO:Ce crystals. This study was carried out in the framework of the Crystal Clear Collaboration (CCC)

  17. Generation of femtosecond laser pulses at 396 nm in K3B6O10Cl crystal

    International Nuclear Information System (INIS)

    Zhang Ning-Hua; Huang Hang-Dong; Tian Wen-Long; Zhu Jiang-Feng; Teng Hao; Fang Shao-Bo; Wei Zhi-Yi; Wu Hong-Ping; Pan Shi-Lie

    2016-01-01

    K 3 B 6 O 10 Cl (KBOC), a new nonlinear optical crystal, shows potential advantages for the generation of deep ultraviolet (UV) light compared with other borate crystals. In this paper we study for the first time the second harmonic generation (SHG) of a femtosecond Ti:sapphire amplifier with this crystal. Laser power is obtained to be as high as 220 mW at the central wavelength of 396 nm with a 1-mm-long crystal, and the maximum SHG conversion efficiency reaches 39.3%. The typical pulse duration is 83 fs. The results show that second harmonic (SH) conversion efficiency has the room to be further improved and that the new nonlinear crystal is very suited to generate the high efficiency deep ultraviolet laser radiation below 266 nm. (paper)

  18. Single Crystal Growth of Pure Co3+ Oxidation State Material LaSrCoO4

    Directory of Open Access Journals (Sweden)

    Hanjie Guo

    2016-08-01

    Full Text Available We report on the single crystal growth of the single-layer perovskite cobaltate LaSrCoO4 that was grown by the optical floating zone method using high oxygen pressures. Phase purity and single crystallinity were confirmed by X-ray diffraction techniques. The pure Co3+ oxidation state was confirmed by X-ray absorbtion spectroscopy measurements. A transition to a spin glass state is observed at ∼7 K in magnetic susceptibility and specific heat measurements.

  19. Pinning-to-barrier crossover in YBa2Cu3O7-δ single crystals

    Science.gov (United States)

    Indenbom, M. V.; van der Beek, C. J.; Berseth, V.; Konczykowski, M.; Holtzberg, F.; Benoit, W.

    1996-03-01

    The behaviour of magnetic flux in high purity untwinned YBa2Cu3O7-δ (YBCO) single crystals is visualised by means of the magneto-optical technique. It is observed that after zero field-cooling at high temperatures near T c , flux penetrates directly to the sample center over a flux free edge area, in contrast to the usual Bean-like flux penetration from the edges. This fact clearly shows that volume pinning becomes negligible compared with the edge barrier. The role of the recently rediscovered geometrical barrier in the crystal magnetisation is discussed.

  20. Near-Band-Edge Optical Responses of CH3NH3PbCl3 Single Crystals: Photon Recycling of Excitonic Luminescence

    Science.gov (United States)

    Yamada, Takumi; Aharen, Tomoko; Kanemitsu, Yoshihiko

    2018-02-01

    The determination of the band gap and exciton energies of lead halide perovskites is very important from the viewpoint of fundamental physics and photonic device applications. By using photoluminescence excitation (PLE) spectra, we reveal the optical properties of CH3NH3PbCl3 single crystals in the near-band-edge energy regime. The one-photon PLE spectrum exhibits the 1 s exciton peak at 3.11 eV. On the contrary, the two-photon PLE spectrum exhibits no peak structure. This indicates photon recycling of excitonic luminescence. By analyzing the spatial distribution of the excitons and photon recycling, we obtain 3.15 eV for the band gap energy and 41 meV for the exciton binding energy.