WorldWideScience

Sample records for ir tunable optical

  1. Widely-tunable and sensitive optical sensor for multi-species detection in the mid-IR

    KAUST Repository

    Alquaity, Awad

    2017-10-05

    Pulsed cavity ringdown spectroscopy (CRDS) technique was used to develop a novel widely-tunable laser-based sensor for sensitive measurements of ethylene, propene, 1-butene and allene in the mid-IR. The use of an external-cavity quantum cascade laser (EC-QCL) enabled the sensor to cover a wide wavelength range from 10 to 11.1 µm (900 – 1000 cm-1) to detect multiple gases relevant to combustion and environment. The sensor operation was validated in a room-temperature static cell using well-characterized absorption lines of carbon dioxide near 938.69 cm-1 and 974.62 cm-1. Detection limits for ethylene, propene, 1-butene, and allene were measured to be 17, 134, 754 and 378 ppb, respectively, at 296 K and 760 Torr for a single-pass path-length of 70 cm. The excellent sensitivity of the optical sensor enabled it to measure the aforementioned gases at levels smaller than 1% of their recommended exposure limits. To the best of our knowledge, this is one of the first successful applications of the pulsed CRDS technique to measure trace levels of multiple gases in the 10 – 11 µm wavelength region.

  2. Widely-tunable and sensitive optical sensor for multi-species detection in the mid-IR

    KAUST Repository

    Alquaity, Awad; Alsaif, Bidoor; Farooq, Aamir

    2017-01-01

    Pulsed cavity ringdown spectroscopy (CRDS) technique was used to develop a novel widely-tunable laser-based sensor for sensitive measurements of ethylene, propene, 1-butene and allene in the mid-IR. The use of an external-cavity quantum cascade laser (EC-QCL) enabled the sensor to cover a wide wavelength range from 10 to 11.1 µm (900 – 1000 cm-1) to detect multiple gases relevant to combustion and environment. The sensor operation was validated in a room-temperature static cell using well-characterized absorption lines of carbon dioxide near 938.69 cm-1 and 974.62 cm-1. Detection limits for ethylene, propene, 1-butene, and allene were measured to be 17, 134, 754 and 378 ppb, respectively, at 296 K and 760 Torr for a single-pass path-length of 70 cm. The excellent sensitivity of the optical sensor enabled it to measure the aforementioned gases at levels smaller than 1% of their recommended exposure limits. To the best of our knowledge, this is one of the first successful applications of the pulsed CRDS technique to measure trace levels of multiple gases in the 10 – 11 µm wavelength region.

  3. Tunable micro-optics

    CERN Document Server

    Duppé, Claudia

    2015-01-01

    Presenting state-of-the-art research into the dynamic field of tunable micro-optics, this is the first book to provide a comprehensive survey covering a varied range of topics including novel materials, actuation concepts and new imaging systems in optics. Internationally renowned researchers present a diverse range of chapters on cutting-edge materials, devices and subsystems, including soft matter, artificial muscles, tunable lenses and apertures, photonic crystals, and complete tunable imagers. Special contributions also provide in-depth treatment of micro-optical characterisation, scanners, and the use of natural eye models as inspiration for new concepts in advanced optics. With applications extending from medical diagnosis to fibre telecommunications, Tunable Micro-optics equips readers with a solid understanding of the broader technical context through its interdisciplinary approach to the realisation of new types of optical systems. This is an essential resource for engineers in industry and academia,...

  4. Tunable laser optics

    CERN Document Server

    Duarte, FJ

    2015-01-01

    This Second Edition of a bestselling book describes the optics and optical principles needed to build lasers. It also highlights the optics instrumentation necessary to characterize laser emissions and focuses on laser-based optical instrumentation. The book emphasizes practical and utilitarian aspects of relevant optics including the essential theory. This revised, expanded, and improved edition contains new material on tunable lasers and discusses relevant topics in quantum optics.

  5. All-optical microscope autofocus based on an electrically tunable lens and a totally internally reflected IR laser.

    Science.gov (United States)

    Bathe-Peters, M; Annibale, P; Lohse, M J

    2018-02-05

    Microscopic imaging at high spatial-temporal resolution over long time scales (minutes to hours) requires rapid and precise stabilization of the microscope focus. Conventional and commercial autofocus systems are largely based on piezoelectric stages or mechanical objective actuators. Objective to sample distance is either measured by image analysis approaches or by hardware modules measuring the intensity of reflected infrared light. We propose here a truly all-optical microscope autofocus taking advantage of an electrically tunable lens and a totally internally reflected infrared probe beam. We implement a feedback-loop based on the lateral position of a totally internally reflected infrared laser on a quadrant photodetector, as an indicator of the relative defocus. We show here how to treat the combined contributions due to mechanical defocus and deformation of the tunable lens. As a result, the sample can be kept in focus without any mechanical movement, at rates up to hundreds of Hertz. The device requires only reflective optics and can be implemented at a fraction of the cost required for a comparable piezo-based actuator.

  6. Broadly tunable picosecond ir source

    International Nuclear Information System (INIS)

    Campillo, A.J.; Hyer, R.C.; Shapiro, S.L.

    1979-01-01

    A completely grating tuned (1.9 to 2.4 μm) picosecond traveling wave IR generator capable of controlled spectral bandwidth operation down to the Fourier Transform limit is reported. Subsequent down conversion in CdSe extends tuning to 10 to 20 μm

  7. Tunable electro-optic filter stack

    Science.gov (United States)

    Fontecchio, Adam K.; Shriyan, Sameet K.; Bellingham, Alyssa

    2017-09-05

    A holographic polymer dispersed liquid crystal (HPDLC) tunable filter exhibits switching times of no more than 20 microseconds. The HPDLC tunable filter can be utilized in a variety of applications. An HPDLC tunable filter stack can be utilized in a hyperspectral imaging system capable of spectrally multiplexing hyperspectral imaging data acquired while the hyperspectral imaging system is airborne. HPDLC tunable filter stacks can be utilized in high speed switchable optical shielding systems, for example as a coating for a visor or an aircraft canopy. These HPDLC tunable filter stacks can be fabricated using a spin coating apparatus and associated fabrication methods.

  8. Ten-watt level picosecond parametric mid-IR source broadly tunable in wavelength

    Science.gov (United States)

    Vyvlečka, Michal; Novák, Ondřej; Roškot, Lukáscaron; Smrž, Martin; Mužík, Jiří; Endo, Akira; Mocek, Tomáš

    2018-02-01

    Mid-IR wavelength range (between 2 and 8 μm) offers perspective applications, such as minimally-invasive neurosurgery, gas sensing, or plastic and polymer processing. Maturity of high average power near-IR lasers is beneficial for powerful mid-IR generation by optical parametric conversion. We utilize in-house developed Yb:YAG thin-disk laser of 100 W average power at 77 kHz repetition rate, wavelength of 1030 nm, and about 2 ps pulse width for pumping of a ten-watt level picosecond mid-IR source. Seed beam is obtained by optical parametric generation in a double-pass 10 mm long PPLN crystal pumped by a part of the fundamental near-IR beam. Tunability of the signal wavelength between 1.46 μm and 1.95 μm was achieved with power of several tens of miliwatts. Main part of the fundamental beam pumps an optical parametric amplification stage, which includes a walk-off compensating pair of 10 mm long KTP crystals. We already demonstrated the OPA output signal and idler beam tunability between 1.70-1.95 μm and 2.18-2.62 μm, respectively. The signal and idler beams were amplified up to 8.5 W and 5 W, respectively, at 42 W pump without evidence of strong saturation. Thus, increase in signal and idler output power is expected for pump power increase.

  9. Oxadiazole-carbazole polymer (POC)-Ir(ppy)3 tunable emitting composites

    Science.gov (United States)

    Bruno, Annalisa; Borriello, Carmela; Di Luccio, Tiziana; Sessa, Lucia; Concilio, Simona; Haque, Saif A.; Minarini, Carla

    2017-04-01

    POC polymer is an oxadiazole-carbazole copolymer we have previously synthetized and established as light emitting material in Organic Light Emitting Devices (OLEDs), although POC quantum yield emission efficiency and color purity still need to be enhanced. On the other hand, tris[2-phenylpyridinato-C2,N]iridium(III) (Ir(ppy)3) complexes, namely Ir(ppy)3 are among the brightest luminophores employed in green light emitting devices. Our aim, in this work, is to take advantage of Ir(ppy)3 bright emission by combining the Ir complex with blue emitting POC to obtain tunable light emitting composites over a wide range of the visible spectrum. Here we have investigated the optical proprieties POC based nanocomposites with different concentrations of Ir(ppy)3, ranging from 1 to 10 wt%. Both spectral and time resolved fluorescence measurements show an efficient energy transfer from the polymer to the dopants, resulting in white-emitting composites. The most intense and stable emission has been found when POC was doped with about 5 wt% concentration of Ir(ppy)3.

  10. One-Dimensional Tunable Photonic-Crystal IR Filter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — MetroLaser proposes to design and develop an innovative narrowband tunable IR filter based on the properties of a one-dimensional photonic crystal structure with a...

  11. One-Dimensional Tunable Photonic-Crystal IR Filter, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — MetroLaser proposes to design and develop an innovative narrowband tunable IR filter based on the properties of a one-dimensional photonic crystal structure with a...

  12. Tunable 'optical activity' in electrorheological fluids

    International Nuclear Information System (INIS)

    Zhao, Q.; Zhao, X.P.

    2005-01-01

    The 'optical activity' of adjustable periodic structure material (SiO 2 and pentaerythrital electrorheological (ER) fluids) is firstly investigated using two kinds of setup. It is found that the rotation angles can be tuned by the external electric field and weight concentrations, and the sign of the rotation angle is negative, so, the used ER fluids are defined as the left-handed optically active substances under the application of electric field. The laser diffraction patterns are also observed in the ER fluids, which indicates the formation of alignment. It is thought that the symmetry breaking of structure induced by applied electric field is the origin of the 'optical activity' in the ER fluids. The electrically tunable 'optical activity' will find innovative applications in displays, optical devices and other fields

  13. Tunable optical absorption in silicene molecules

    KAUST Repository

    Mokkath, Junais Habeeb; Schwingenschlö gl, Udo

    2016-01-01

    Two-dimensional materials with a tunable band gap that covers a wide range of the solar spectrum hold great promise for sunlight harvesting. For this reason, we investigate the structural, electronic, and optical properties of silicene molecules using time dependent density functional theory. We address the influence of the molecular size, buckling, and charge state as well as that of a dielectric environment. Unlike planar graphene molecules, silicene molecules prefer to form low-buckled structures with strong visible to ultraviolet optical response. We also identify molecular plasmons.

  14. Tunable optical absorption in silicene molecules

    KAUST Repository

    Mokkath, Junais Habeeb

    2016-07-13

    Two-dimensional materials with a tunable band gap that covers a wide range of the solar spectrum hold great promise for sunlight harvesting. For this reason, we investigate the structural, electronic, and optical properties of silicene molecules using time dependent density functional theory. We address the influence of the molecular size, buckling, and charge state as well as that of a dielectric environment. Unlike planar graphene molecules, silicene molecules prefer to form low-buckled structures with strong visible to ultraviolet optical response. We also identify molecular plasmons.

  15. Electro-optical tunable birefringent filter

    Science.gov (United States)

    Levinton, Fred M [Princeton, NJ

    2012-01-31

    An electrically tunable Lyot type filter is a Lyot that include one or more filter elements. Each filter element may have a planar, solid crystal comprised of a material that exhibits birefringence and is electro-optically active. Transparent electrodes may be coated on each face of the crystal. An input linear light polarizer may be located on one side of the crystal and oriented at 45 degrees to the optical axis of the birefringent crystal. An output linear light polarizer may be located on the other side of the crystal and oriented at -45 degrees with respect to the optical axis of the birefringent crystal. When an electric voltage is applied between the electrodes, the retardation of the crystal changes and so does the spectral transmission of the optical filter.

  16. Tunable optical coherence tomography in the infrared range using visible photons

    Science.gov (United States)

    Paterova, Anna V.; Yang, Hongzhi; An, Chengwu; Kalashnikov, Dmitry A.; Krivitsky, Leonid A.

    2018-04-01

    Optical coherence tomography (OCT) is an appealing technique for bio-imaging, medicine, and material analysis. For many applications, OCT in mid- and far-infrared (IR) leads to significantly more accurate results. Reported mid-IR OCT systems require light sources and photodetectors which operate in mid-IR range. These devices are expensive and need cryogenic cooling. Here, we report a proof-of-concept demonstration of a wavelength tunable IR OCT technique with detection of only visible range photons. Our method is based on the nonlinear interference of frequency correlated photon pairs. The nonlinear crystal, introduced in the Michelson-type interferometer, generates photon pairs with one photon in the visible and another in the IR range. The intensity of detected visible photons depends on the phase and loss of IR photons, which interact with the sample under study. This enables us to characterize sample properties and perform imaging in the IR range by detecting visible photons. The technique possesses broad wavelength tunability and yields a fair axial and lateral resolution, which can be tailored to the specific application. The work contributes to the development of versatile 3D imaging and material characterization systems working in a broad range of IR wavelengths, which do not require the use of IR-range light sources and photodetectors.

  17. Temperature control and measurement with tunable femtosecond optical tweezers

    Science.gov (United States)

    Mondal, Dipankar; Goswami, Debabrata

    2016-09-01

    We present the effects of wavelength dependent temperature rise in a femtosecond optical tweezers. Our experiments involve the femtosecond trapping laser tunable from 740-820 nm at low power 25 mW to cause heating in the trapped volume within a homogeneous solution of sub micro-molar concentration of IR dye. The 780 nm high repetition rate laser acts as a resonant excitation source which helps to create the local heating effortlessly within the trapping volume. We have used both position autocorrelation and equipartion theorem to evaluate temperature at different wavelength having different absorption coefficient. Fixing the pulse width in the temporal domain gives constant bandwidth at spatial domain, which makes our system behave as a tunable temperature rise device with high precision. This observation leads us to calculate temperature as well as viscosity within the vicinity of the trapping zone. A mutual energy transfer occurs between the trapped bead and solvents that leads to transfer the thermal energy of solvents into the kinetic energy of the trap bead and vice-versa. Thus hot solvated molecules resulting from resonant and near resonant excitation of trapping wavelength can continuously dissipate heat to the trapped bead which will be reflected on frequency spectrum of Brownian noise exhibited by the bead. Temperature rise near the trapping zone can significantly change the viscosity of the medium. We observe temperature rise profile according to its Gaussian shaped absorption spectrum with different wavelength.

  18. Optically controlled tunable dispersion compensators based on pumped fiber gratings.

    Science.gov (United States)

    Shu, Xuewen; Sugden, Kate; Bennion, Ian

    2011-08-01

    We demonstrate optically tunable dispersion compensators based on pumping fiber Bragg gratings made in Er/Yb codoped fiber. The tunable dispersion for a chirped grating and also a uniform-period grating was successfully demonstrated in the experiment. The dispersion of the chirped grating was tuned from 900 to 1990 ps/nm and also from -600 to -950 ps/nm in the experiment. © 2011 Optical Society of America

  19. Liquid lens with double tunable surfaces for large power tunability and improved optical performance

    International Nuclear Information System (INIS)

    Li, Lei; Wang, Qiong-Hua; Jiang, Wei

    2011-01-01

    In this paper we propose a liquid lens with two tunable interfaces formed by two kinds of immiscible liquids. The proposed liquid lens uses liquid pressure to change the shape of the interfaces. It can provide a large tunable range of optical power and improved optical performance. By applying suitable liquids the gravity effect can also be negligible. To prove the principles, a liquid lens with 7 mm aperture was fabricated. The optical performance indicates that the proposed liquid lens can provide a large tunable range of both positive and negative powers even using liquids with small differences in refractive indices. The resolution is better than 50 lp mm −1 under white light environment. The spherical aberration and coma are also largely reduced. The proposed liquid lens can also provide the optical designer with the freedom to choose the combination of liquids to reduce or even correct aberrations

  20. Tunable photonic bandgap fiber based devices for optical networks

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Scolari, Lara; Rottwitt, Karsten

    2005-01-01

    In future all optical networks one of the enabling technologies is tunable elements including reconfigurable routers, switches etc. Thus, the development of a technology platform that allows construction of tuning components is critical. Lately, microstructured optical fibers, filled with liquid......, for example a liquid crystal that changes optical properties when subjected to, for example, an optical or an electrical field. The utilization of these two basic properties allows design of tunable optical devices for optical networks. In this work, we focus on applications of such devices and discuss recent...... crystals, have proven to be a candidate for such a platform. Microstructured optical fibers offer unique wave-guiding properties that are strongly related to the design of the air holes in the cladding of the fiber. These wave-guiding properties may be altered by filling the air holes with a material...

  1. IV-VI mid-IR tunable lasers and detectors with external resonant cavities

    Science.gov (United States)

    Zogg, H.; Rahim, M.; Khiar, A.; Fill, M.; Felder, F.; Quack, N.; Blunier, S.; Dual, J.

    2009-08-01

    Wavelength tunable emitters and detectors in the mid-IR wavelength region allow applications including thermal imaging and spectroscopy. Such devices may be realized using a resonant cavity. By mechanically changing the cavity length with MEMS mirror techniques, the wavelengths may be tuned over a considerable range. Vertical external cavity surface emitting lasers (VECSEL) may be applied for gas spectroscopy. Resonant cavity enhanced detectors (RCED) are sensitive at the cavity resonance only. They may be applied for low resolution spectroscopy, and, when arrays of such detectors are realized, as multicolor IR-FPA or IR-AFPA (IR-adaptive focal plane arrays). We review mid-infrared RCEDs and VECSELs using narrow gap IV-VI (lead chalcogenide) materials like PbTe and PbSe as the active medium. IV-VIs are fault tolerant and allow easy wavelength tuning. The VECSELs operate up to above room temperature and emit in the 4 - 5 μm range with a PbSe active layer. RCEDs with PbTe absorbing layers above 200 K operating temperature have higher sensitivities than the theoretical limit for a similar broad-band detector coupled with a passive tunable band-filter.

  2. Tunable thin-film optical filters for hyperspectral microscopy

    Science.gov (United States)

    Favreau, Peter F.; Rich, Thomas C.; Prabhat, Prashant; Leavesley, Silas J.

    2013-02-01

    Hyperspectral imaging was originally developed for use in remote sensing applications. More recently, it has been applied to biological imaging systems, such as fluorescence microscopes. The ability to distinguish molecules based on spectral differences has been especially advantageous for identifying fluorophores in highly autofluorescent tissues. A key component of hyperspectral imaging systems is wavelength filtering. Each filtering technology used for hyperspectral imaging has corresponding advantages and disadvantages. Recently, a new optical filtering technology has been developed that uses multi-layered thin-film optical filters that can be rotated, with respect to incident light, to control the center wavelength of the pass-band. Compared to the majority of tunable filter technologies, these filters have superior optical performance including greater than 90% transmission, steep spectral edges and high out-of-band blocking. Hence, tunable thin-film optical filters present optical characteristics that may make them well-suited for many biological spectral imaging applications. An array of tunable thin-film filters was implemented on an inverted fluorescence microscope (TE 2000, Nikon Instruments) to cover the full visible wavelength range. Images of a previously published model, GFP-expressing endothelial cells in the lung, were acquired using a charge-coupled device camera (Rolera EM-C2, Q-Imaging). This model sample presents fluorescently-labeled cells in a highly autofluorescent environment. Linear unmixing of hyperspectral images indicates that thin-film tunable filters provide equivalent spectral discrimination to our previous acousto-optic tunable filter-based approach, with increased signal-to-noise characteristics. Hence, tunable multi-layered thin film optical filters may provide greatly improved spectral filtering characteristics and therefore enable wider acceptance of hyperspectral widefield microscopy.

  3. A Continuously Tunable Erbium-Doped Fibre Laser Using Tunable Fibre Bragg Gratings and Optical Circulator

    International Nuclear Information System (INIS)

    Peng, Liu; Feng-Ping, Yan; Jian, Li; Lin, Wang; Ti-Gang, Ning; Tao-Rong, Gong; Shui-Sheng, Jian

    2008-01-01

    A continuously tunable erbium-doped fibre laser (TEDFL) based on tunable fibre Bragger grating (TFBG) and a three-port optical circulator (OC) is proposed and demonstrated. The OC acts as a 100%-reflective mirror. A strain-induced uniform fibre Bragger grating (FBG) which functions as a partial-reflecting mirror is implemented in the linear cavity. By applying axial strain onto the TFBG, a continuously tunable lasing output can be realized. The wavelength tuning range covers approximately 7.00nm in C band (from 1543.6161 to 1550.3307nm). The side mode suppression ratio (SMSR) is better than 50 dB, and the 3 dB bandwidth of the laser is less than 0.01 nm. Moreover, an array waveguide grating (AWG) is inserted into the cavity for wavelength preselecting, and a 50 km transmission experiment was performed using our TEDFL at a 10Gb/s modulation rate

  4. Properties of transition metal-doped zinc chalcogenide crystals for tunable IR laser radiation

    International Nuclear Information System (INIS)

    DeLoach, L.D.; Page, R.H.; Wilke, G.D.

    1995-01-01

    The spectroscopic properties of Cr 2+ , Co 2+ , and Ni 2+ -doped single crystals of ZnS, ZnSe, and ZnTe have been investigated to understand their potential application as mid-IR tunable solid-state laser media. The spectroscopy indicated divalent Cr was the most favorable candidate for efficient room temperature lasing, and accordingly, a laser-pumped laser demonstration of Cr:ZnS and Cr:ZnSe has been performed. The lasers' output were peaked at ∼ 2.35 μm and the highest measured slope efficiencies were ∼ 20% in both cases

  5. Tunable optical assembly with vibration dampening

    Science.gov (United States)

    Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

    2009-01-01

    An optical assembly is formed by one or more piezoelectric fiber composite actuators having one or more optical fibers coupled thereto. The optical fiber(s) experiences strain when actuation voltage is applied to the actuator(s). Light passing through the optical fiber(s) is wavelength tuned by adjusting the actuation voltage.

  6. 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...

  7. An optical tunable filter array based on LCOS phase grating

    Science.gov (United States)

    Feng, Dong; Wan, Zhujun; Chen, Xu; Yan, Shijia; Luo, Zhixiang

    2018-01-01

    This paper reports an optical tunable filter array (TFA) based on a LCOS (liquid crystal on silicon) chip. The input broadband optical beam is first dispersed by a bulk grating and then incident on the LCOS chip. The LCOS chip is phase-only modulated and constructed as a dynamic reflective phase grating. The phase modulation is adjusted to meet the Littrow angle for a specified passband wavelength and thus the optical beam corresponding to this wavelength is steered to the output. The input/output optical beams are coupled to optical fibers with a dual-fiber collimator. Four dualfiber collimators are vertically aligned as the inputs/outputs and the pixels of the LCOS chip are vertically allocated as four independent zones. Thus the device can act as a 4-channel TFA, which is assembled and functionally demonstrated.

  8. Tunable High Harmonic Generation driven by a Visible Optical Parametric Amplifier

    Directory of Open Access Journals (Sweden)

    Keathley P.

    2013-03-01

    Full Text Available We studied high-harmonic generation (HHG in Ar, Ne and He gas jets using a broadly tunable, high-energy optical parametric amplifier (OPA in the visible wavelength range. We optimized the noncollinear OPA to deliver tunable, femtosecond pulses with 200-500 μJ energy at 1-kHz repetition rate with excellent spatiotemporal properties, suitable for HHG experiments. By tuning the central wavelength of the OPA while keeping energy, duration and beam size constant, we experimentally studied the scaling law of conversion efficiency and cut-off energy with the driver wavelength in argon and helium respectively. Our measurements show a λ−5.9±0.9 wavelength dependence of the conversion efficiency and a λ1.7±0.2 dependence of the HHG cut-off photon energy over the full visible range in agreement with previous experiments of near- and mid-IR wavelengths. By tuning the central wavelength of the driver source and changing the gas, the high order harmonic spectra in the extreme ultraviolet cover the full range of photon energy between ~25 eV and ~100 eV. Due to the high coherence intrinsic in HHG, as well as the broad and continuous tunability in the extreme UV range, a high energy, high repetition rate version of this source might be an ideal seed for free electron lasers.

  9. Wavelength-tunable laser based on nonlinear dispersive-wave generation in a tapered optical waveguide

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a method and a wavelength tunable laser comprising a first laser source configured to emit a first optical pulse having a pump wavelength, the first optical pulse being emitted in a first longitudinal direction. Furthermore, the wavelength tunable laser comprises...... a waveguide extending in the first longitudinal direction, the waveguide having longitudinally varying phase matching conditions, the waveguide being configured to generate a second optical pulse with a centre wavelength upon receiving the first optical pulse, wherein the wavelength tunable laser...... is configured to tune the centre wavelength of the second optical pulse by varying at least one pulse property of the first optical pulse....

  10. Meta-structure and tunable optical device including the same

    Science.gov (United States)

    Han, Seunghoon; Papadakis, Georgia Theano; Atwater, Harry

    2017-12-26

    A meta-structure and a tunable optical device including the same are provided. The meta-structure includes a plurality of metal layers spaced apart from one another, an active layer spaced apart from the plurality of metal layers and having a carrier concentration that is tuned according to an electric signal applied to the active layer and the plurality of metal layers, and a plurality of dielectric layers spaced apart from one another and each having one surface contacting a metal layer among the plurality of metal layers and another surface contacting the active layer.

  11. Optical and IR light curves of VV Puppis

    International Nuclear Information System (INIS)

    Szkody, P.; Bailey, J.A.; Hough, J.H.

    1983-01-01

    We present optical (0.36 to 0.6 μm) light curves with time resolutions of seconds and infrared (IR) (1.25 to 2.2 μm) light curves with time resolutions of minutes for VV Puppis during a high state. The optical light curves show a single hump with largest amplitude in the V filter, while the IR light curves show a double hump sinusoidal variation. Flickering is evident in both the optical and IR light curves, with the largest amplitude in optical B light. Through subtraction of the low state fluxes from our high state values, we obtain a flux distribution of the accretion column which peaks at 0.55 μm and becomes #betta# 2 in the IR, consistent with current cyclotron models. Comparison of the observed IR variations throughout the orbit with the expected variations due to an M4 star heated by an accretion column at an inclination of 66 0 suggests that the IR light is a combination of the secondary star plus contributions from two emitting poles. (author)

  12. IR-laser assisted additive freeform optics manufacturing.

    Science.gov (United States)

    Hong, Zhihan; Liang, Rongguang

    2017-08-02

    Computer-controlled additive manufacturing (AM) processes, also known as three-dimensional (3D) printing, create 3D objects by the successive adding of a material or materials. While there have been tremendous developments in AM, the 3D printing of optics is lagging due to the limits in materials and tight requirements for optical applicaitons. We propose a new precision additive freeform optics manufacturing (AFOM) method using an pulsed infrared (IR) laser. Compared to ultraviolet (UV) curable materials, thermally curable optical silicones have a number of advantages, such as strong UV stability, non-yellowing, and high transmission, making it particularly suitable for optical applications. Pulsed IR laser radiation offers a distinct advantage in processing optical silicones, as the high peak intensity achieved in the focal region allows for curing the material quickly, while the brief duration of the laser-material interaction creates a negligible heat-affected zone.

  13. Tunable enhanced optical absorption of graphene using plasmonic perfect absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yijun [Institute of Optoelectronic Technology, Department of Electronic Engineering, Xiamen University, Xiamen 361005 (China); Institute of Electromagnetics and Acoustics, Department of Electronic Science, Xiamen University, Xiamen 361005 (China); Zhu, Jinfeng, E-mail: nanoantenna@hotmail.com [Institute of Electromagnetics and Acoustics, Department of Electronic Science, Xiamen University, Xiamen 361005 (China); Liu, Qing Huo [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2015-01-26

    Enhancement and manipulation of light absorption in graphene is a significant issue for applications of graphene-based optoelectronic devices. In order to achieve this purpose in the visible region, we demonstrate a design of a graphene optical absorber inspired by metal-dielectric-metal metamaterial for perfect absorption of electromagnetic waves. The optical absorbance ratios of single and three atomic layer graphene are enhanced up to 37.5% and 64.8%, respectively. The graphene absorber shows polarization-dependence and tolerates a wide range of incident angles. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.

  14. Fully reconfigurable 2x2 optical cross-connect using tunable wavelength switching modules

    DEFF Research Database (Denmark)

    Liu, Fenghai; Zheng, Xueyan; Pedersen, Rune Johan Skullerud

    2001-01-01

    A modular tunable wavelength switching module is proposed and used to construct 2x2 fully reconfigurable optical cross-connects. Large size optical switch is avoided in the OXC and it is easy to upgrade to more wavelength channels.......A modular tunable wavelength switching module is proposed and used to construct 2x2 fully reconfigurable optical cross-connects. Large size optical switch is avoided in the OXC and it is easy to upgrade to more wavelength channels....

  15. Integrated all optical transmodulator circuits with non-linear gain elements and tunable optical fibers

    NARCIS (Netherlands)

    Kuindersma, P.I.; Leijtens, X.J.M.; Zantvoort, van J.H.C.; Waardt, de H.

    2012-01-01

    We characterize integrated InP circuits for high speed ‘all-optical’ signal processing. Single chip circuits act as optical transistors. Transmodulation is performed by non-linear gain sections. Integrated tunable filters give signal equalization in time domain.

  16. Dynamically tunable optical bottles from an optical fiber

    DEFF Research Database (Denmark)

    Chen, Yuhao; Yan, Lu; Rishøj, Lars Søgaard

    2012-01-01

    Optical fibers have long been used to impose spatial coherence to shape free-space optical beams. Recent work has shown that one can use higher order fiber modes to create more exotic beam profiles. We experimentally generate optical bottles from Talbot imaging in the coherent superposition of two...... fiber modes excited with long period gratings, and obtain a 28 μm × 6 μm bottle with controlled contrast up to 10.13 dB. Our geometry allows for phase tuning of one mode with respect to the other, which enables us to dynamically move the bottle in free space....

  17. Experimental demonstration of software defined data center optical networks with Tbps end-to-end tunability

    Science.gov (United States)

    Zhao, Yongli; Zhang, Jie; Ji, Yuefeng; Li, Hui; Wang, Huitao; Ge, Chao

    2015-10-01

    The end-to-end tunability is important to provision elastic channel for the burst traffic of data center optical networks. Then, how to complete the end-to-end tunability based on elastic optical networks? Software defined networking (SDN) based end-to-end tunability solution is proposed for software defined data center optical networks, and the protocol extension and implementation procedure are designed accordingly. For the first time, the flexible grid all optical networks with Tbps end-to-end tunable transport and switch system have been online demonstrated for data center interconnection, which are controlled by OpenDayLight (ODL) based controller. The performance of the end-to-end tunable transport and switch system has been evaluated with wavelength number tuning, bit rate tuning, and transmit power tuning procedure.

  18. Optically Tunable Magnetoresistance Effect: From Mechanism to Novel Device Application.

    Science.gov (United States)

    Liu, Pan; Lin, Xiaoyang; Xu, Yong; Zhang, Boyu; Si, Zhizhong; Cao, Kaihua; Wei, Jiaqi; Zhao, Weisheng

    2017-12-28

    The magnetoresistance effect in sandwiched structure describes the appreciable magnetoresistance effect of a device with a stacking of two ferromagnetic layers separated by a non-magnetic layer (i.e., a sandwiched structure). The development of this effect has led to the revolution of memory applications during the past decades. In this review, we revisited the magnetoresistance effect and the interlayer exchange coupling (IEC) effect in magnetic sandwiched structures with a spacer layer of non-magnetic metal, semiconductor or organic thin film. We then discussed the optical modulation of this effect via different methods. Finally, we discuss various applications of these effects and present a perspective to realize ultralow-power, high-speed data writing and inter-chip connection based on this tunable magnetoresistance effect.

  19. Tunable Optical Properties of Metal Nanoparticle Sol-Gel Composites

    Science.gov (United States)

    Smith, David D.; Snow, Lanee A.; Sibille, Laurent; Ignont, Erica

    2001-01-01

    We demonstrate that the linear and non-linear optical properties of sol-gels containing metal nanoparticles are highly tunable with porosity. Moreover, we extend the technique of immersion spectroscopy to inhomogeneous hosts, such as aerogels, and determine rigorous bounds for the average fractional composition of each component, i.e., the porosity of the aerogel, or equivalently, for these materials, the catalytic dispersion. Sol-gels containing noble metal nanoparticles were fabricated and a significant blue-shift in the surface plasmon resonance (SPR) was observed upon formation of an aerogel, as a result of the decrease in the dielectric constant of the matrix upon supercritical extraction of the solvent. However, as a result of chemical interface damping and aggregation this blue-shift does not strictly obey standard effective medium theories. Mitigation of these complications is achieved by avoiding the use of alcohol and by annealing the samples in a reducing atmosphere.

  20. Tunable Optical True-Time Delay Devices Would Exploit EIT

    Science.gov (United States)

    Kulikov, Igor; DiDomenico, Leo; Lee, Hwang

    2004-01-01

    Tunable optical true-time delay devices that would exploit electromagnetically induced transparency (EIT) have been proposed. Relative to prior true-time delay devices (for example, devices based on ferroelectric and ferromagnetic materials) and electronically controlled phase shifters, the proposed devices would offer much greater bandwidths. In a typical envisioned application, an optical pulse would be modulated with an ultra-wideband radio-frequency (RF) signal that would convey the information that one seeks to communicate, and it would be required to couple differently delayed replicas of the RF signal to the radiating elements of a phased-array antenna. One or more of the proposed devices would be used to impose the delays and/or generate the delayed replicas of the RF-modulated optical pulse. The beam radiated or received by the antenna would be steered by use of a microprocessor-based control system that would adjust operational parameters of the devices to tune the delays to the required values. EIT is a nonlinear quantum optical interference effect that enables the propagation of light through an initially opaque medium. A suitable medium must have, among other properties, three quantum states (see Figure 1): an excited state (state 3), an upper ground state (state 2), and a lower ground state (state 1). These three states must form a closed system that exhibits no decays to other states in the presence of either or both of two laser beams: (1) a probe beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 1; and (2) a coupling beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 2. The probe beam is the one that is pulsed and modulated with an RF signal.

  1. MTF measurement of IR optics in different temperature ranges

    Science.gov (United States)

    Bai, Alexander; Duncker, Hannes; Dumitrescu, Eugen

    2017-10-01

    Infrared (IR) optical systems are at the core of many military, civilian and manufacturing applications and perform mission critical functions. To reliably fulfill the demanding requirements imposed on today's high performance IR optics, highly accurate, reproducible and fast lens testing is of crucial importance. Testing the optical performance within different temperature ranges becomes key in many military applications. Due to highly complex IR-Applications in the fields of aerospace, military and automotive industries, MTF Measurement under realistic environmental conditions become more and more relevant. A Modulation Transfer Function (MTF) test bench with an integrated thermal chamber allows measuring several sample sizes in a temperature range from -40 °C to +120°C. To reach reliable measurement results under these difficult conditions, a specially developed temperature stable design including an insulating vacuum are used. The main function of this instrument is the measurement of the MTF both on- and off-axis at up to +/-70° field angle, as well as measurement of effective focal length, flange focal length and distortion. The vertical configuration of the system guarantees a small overall footprint. By integrating a high-resolution IR camera with focal plane array (FPA) in the detection unit, time consuming measurement procedures such as scanning slit with liquid nitrogen cooled detectors can be avoided. The specified absolute accuracy of +/- 3% MTF is validated using internationally traceable reference optics. Together with a complete and intuitive software solution, this makes the instrument a turn-key device for today's state-of- the-art optical testing.

  2. Plasmonic Gold Nanorod Dispersions with Electrical and Optical Tunability

    Science.gov (United States)

    Grabowski, Christopher; Mahoney, Clare; Park, Kyoungweon; Jawaid, Ali; White, Timothy; Vaia, Richard

    The transmissive, absorptive, electrical, and thermal properties of plasmonic gold nanorods (NRs) have led to their employment in a broad range of applications. These electro-optical properties - governed by their size, shape, and composition - are widely and precisely tunable during synthesis. Gold NRs show promise for large scale optical elements as they have been demonstrated to align faster than liquid crystal films (μs) at low fields (1 V/ μm). Successfully dispersing a high volume fraction of gold NRs requires a strategy to control particle-particle separation and thus avoid aggregation. Herein, we discuss the role of theta temperature and the ability to swell or collapse the chains of polymer-grafted gold NRs to alter the interaction potential between particles. UV-Vis spectroscopy, scattering, and electrical susceptibility characterization methods were employed to determine nanoparticle dispersion along with the degree of gold NR alignment. The development of new agile photonic materials, controllable with both light and electric fields, will help address emerging needs in laser hardening (agile filters) and variable transmission visors.

  3. Electroactive semi-interpenetrating polymer networks architecture with tunable IR reflectivity

    Science.gov (United States)

    Chevrot, C.; Teyssié, D.; Verge, P.; Goujon, L.; Tran-Van, F.; Vidal, F.; Aubert, P. H.; Peralta, S.; Sauques, L.

    2011-04-01

    A promising alternative of multi-layered devices showing electrochromic properties results from the design of a self-supported semi-interpenetrating polymer network (semi-IPN) including an electronic conductive polymer (ECP) formed within. The formation of the ECP in the network has already been described by oxidative polymerization using iron trichloride as an oxidant and leading to conducting semi-IPN with mixed electronic and ionic conductivities as well as convenient mechanical properties. This presentation relates to the elaboration of such semi-IPN using polyethyleneoxide (PEO) network or a PEO/NBR (Nitrile Butadiene Rubber) IPN in which a linear poly (3,4-ethylenedioxythiophene) (PEDOT) is formed symmetrically and selectively as very thin layers very next to the two main faces of the film matrix. PEO/PEDOT semi-IPNs lead to interesting optical reflective properties in the IR between 0.8 and 25 μm. Reflectance contrasts up to 35 % is observed when, after swelling in an ionic liquid, a low voltage is applied between the two main faces of the film. However the low flexibility and brittleness of the film and a slow degradation in air at temperature up from 60°C prompted to replace the PEO matrix by a flexible PEO/NBR IPN one. Indeed, the combination of NBR and PEO in an IPN leads to materials possessing flexible properties, good ionic conductivity at 25°C as well as a better resistance to thermal ageing. Finally, NBR/PEO/PEDOT semi-IPNs allow observing comparable reflectance contrast in the IR range than those shown by PEO/PEDOT semi-IPNs.

  4. Studies of Neutron Stars at Optical/IR Wavelengths

    OpenAIRE

    Mignani, R. P.; Bagnulo, S.; De Luca, A.; Israel, G. L.; Curto, G. Lo; Motch, C.; Perna, R.; Rea, N.; Turolla, R.; Zane, S.

    2006-01-01

    In the last years, optical studies of Isolated Neutron Stars (INSs) have expanded from the more classical rotation-powered ones to other categories, like the Anomalous X-ray Pulsars (AXPs) and the Soft Gamma-ray Repeaters (SGRs), which make up the class of the magnetars, the radio-quiet INSs with X-ray thermal emission and, more recently, the enigmatic Compact Central Objects (CCOs) in supernova remnants. Apart from 10 rotation-powered pulsars, so far optical/IR counterparts have been found f...

  5. Yb-fiber-pumped mid-infrared picosecond optical parametric oscillator tunable across 6.2-6.7 µm

    Science.gov (United States)

    Kumar, S. Chaitanya; Casals, J. Canals; Parsa, S.; Zawilski, K. T.; Schunemann, P. G.; Ebrahim-Zadeh, M.

    2018-06-01

    We report a high-average-power picosecond optical parametric oscillator (OPO) tunable in the mid-infrared (mid-IR) based on CdSiP2 synchronously pumped by an Yb-fiber laser at 80 MHz repetition rate. Successful operation of this high-repetition-rate singly-resonant picosecond OPO has been enabled by the improved CSP crystal quality over a long interaction length. The OPO can be tuned across 1264-1284 nm in the near-IR signal and 6205-6724 nm in the mid-IR idler by temperature tuning the CSP crystal over 39-134 °C. By deploying a 5% output coupler for the resonant signal, we have extracted up to 44 mW of average power in the near-IR and up to 95 mW of non-resonant idler power at 6205 nm at 6.3% total conversion efficiency, with > 50 mW over > 55% of the mid-IR tuning range. We have investigated temperature-tuning characteristics of the OPO and compared the data with the theoretical calculations using the recent Sellmeier and thermo-optic coefficients for CdSiP2. The signal pulses from the OPO exhibit a Gaussian pulse duration of 19 ps centered at 1284 nm. We have also studied the output power stability of the OPO, resulting in a passive stability better than 1.9% rms for the near-IR signal and 2.4% rms for the mid-IR idler, measured over > 17 h, with both beams in high spatial quality.

  6. Tunable Bandgap and Optical Properties of Black Phosphorene Nanotubes

    Directory of Open Access Journals (Sweden)

    Chunmei Li

    2018-02-01

    Full Text Available Black phosphorus (BP, a new two-dimensional material, has been the focus of scientists’ attention. BP nanotubes have potential in the field of optoelectronics due to their low-dimensional effects. In this work, the bending strain energy, electronic structure, and optical properties of BP nanotubes were investigated by using the first-principles method based on density functional theory. The results show that these properties are closely related to the rolling direction and radius of the BP nanotube. All the calculated BP nanotube properties show direct bandgaps, and the BP nanotubes with the same rolling direction express a monotone increasing trend in the value of bandgap with a decrease in radius, which is a stacking effect of the compression strain on the inner atoms and the tension strain on the outer atoms. The bending strain energy of the zigzag phosphorene nanotubes (zPNTs is higher than that of armchair phosphorene nanotubes (aPNT with the same radius of curvature due to the anisotropy of the BP’s structure. The imaginary part of the dielectric function, the absorption range, reflectivity, and the imaginary part of the refractive index of aPNTs have a wider range than those of zPNTs, with higher values overall. As a result, tunable BP nanotubes are suitable for optoelectronic devices, such as lasers and diodes, which function in the infrared and ultra-violet regions, and for solar cells and photocatalysis.

  7. THE CHANDRA COSMOS LEGACY SURVEY: OPTICAL/IR IDENTIFICATIONS

    International Nuclear Information System (INIS)

    Marchesi, S.; Civano, F.; Urry, C. M.; Elvis, M.; Salvato, M.; Brusa, M.; Lanzuisi, G.; Vignali, C.; Comastri, A.; Gilli, R.; Zamorani, G.; Cappelluti, N.; Hasinger, G.; Miyaji, T.; Treister, E.; Allevato, V.; Finoguenov, A.; Cardamone, C.; Griffiths, R. E.; Karim, A.

    2016-01-01

    We present the catalog of optical and infrared counterparts of the Chandra  COSMOS-Legacy  Survey, a 4.6 Ms Chandra  program on the 2.2 deg 2 of the COSMOS field, combination of 56 new overlapping observations obtained in Cycle 14 with the previous C-COSMOS survey. In this Paper we report the i, K, and 3.6 μm identifications of the 2273 X-ray point sources detected in the new Cycle 14 observations. We use the likelihood ratio technique to derive the association of optical/infrared (IR) counterparts for 97% of the X-ray sources. We also update the information for the 1743 sources detected in C-COSMOS, using new K and 3.6 μm information not available when the C-COSMOS analysis was performed. The final catalog contains 4016 X-ray sources, 97% of which have an optical/IR counterpart and a photometric redshift, while ≃54% of the sources have a spectroscopic redshift. The full catalog, including spectroscopic and photometric redshifts and optical and X-ray properties described here in detail, is available online. We study several X-ray to optical (X/O) properties: with our large statistics we put better constraints on the X/O flux ratio locus, finding a shift toward faint optical magnitudes in both soft and hard X-ray band. We confirm the existence of a correlation between X/O and the the 2–10 keV luminosity for Type 2 sources. We extend to low luminosities the analysis of the correlation between the fraction of obscured AGNs and the hard band luminosity, finding a different behavior between the optically and X-ray classified obscured fraction

  8. THE CHANDRA COSMOS LEGACY SURVEY: OPTICAL/IR IDENTIFICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, S.; Civano, F.; Urry, C. M. [Yale Center for Astronomy and Astrophysics, 260 Whitney Avenue, New Haven, CT 06520 (United States); Elvis, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Salvato, M. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching bei München (Germany); Brusa, M.; Lanzuisi, G.; Vignali, C. [Dipartimento di Fisica e Astronomia, Università di Bologna, viale Berti Pichat 6/2, I-40127 Bologna (Italy); Comastri, A.; Gilli, R.; Zamorani, G.; Cappelluti, N. [INAF—Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Hasinger, G. [Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822 (United States); Miyaji, T. [Instituto de Astronomía sede Ensenada, Universidad Nacional Autónoma de México, Km. 103, Carret. Tijunana-Ensenada, Ensenada, BC (Mexico); Treister, E. [Universidad de Concepción, Departamento de Astronomía, Casilla 160-C, Concepción (Chile); Allevato, V.; Finoguenov, A. [Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-00014 Helsinki (Finland); Cardamone, C. [Department of Science, Wheelock College, Boston, MA 02215 (United States); Griffiths, R. E. [Physics and Astronomy Dept., Natural Sciences Division, University of Hawaii at Hilo, 200 W. Kawili Street, Hilo, HI 96720 (United States); Karim, A. [Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany); and others

    2016-01-20

    We present the catalog of optical and infrared counterparts of the Chandra  COSMOS-Legacy  Survey, a 4.6 Ms Chandra  program on the 2.2 deg{sup 2} of the COSMOS field, combination of 56 new overlapping observations obtained in Cycle 14 with the previous C-COSMOS survey. In this Paper we report the i, K, and 3.6 μm identifications of the 2273 X-ray point sources detected in the new Cycle 14 observations. We use the likelihood ratio technique to derive the association of optical/infrared (IR) counterparts for 97% of the X-ray sources. We also update the information for the 1743 sources detected in C-COSMOS, using new K and 3.6 μm information not available when the C-COSMOS analysis was performed. The final catalog contains 4016 X-ray sources, 97% of which have an optical/IR counterpart and a photometric redshift, while ≃54% of the sources have a spectroscopic redshift. The full catalog, including spectroscopic and photometric redshifts and optical and X-ray properties described here in detail, is available online. We study several X-ray to optical (X/O) properties: with our large statistics we put better constraints on the X/O flux ratio locus, finding a shift toward faint optical magnitudes in both soft and hard X-ray band. We confirm the existence of a correlation between X/O and the the 2–10 keV luminosity for Type 2 sources. We extend to low luminosities the analysis of the correlation between the fraction of obscured AGNs and the hard band luminosity, finding a different behavior between the optically and X-ray classified obscured fraction.

  9. IR OPTICS MEASUREMENT WITH LINEAR COUPLING'S ACTION-ANGLE PARAMETERIZATION

    International Nuclear Information System (INIS)

    LUO, Y.; BAI, M.; PILAT, R.; SATOGATA, T.; TRBOJEVIC, D.

    2005-01-01

    A parameterization of linear coupling in action-angle coordinates is convenient for analytical calculations and interpretation of turn-by-turn (TBT) beam position monitor (BPM) data. We demonstrate how to use this parameterization to extract the twiss and coupling parameters in interaction regions (IRs), using BPMs on each side of the long IR drift region. The example of TBT BPM analysis was acquired at the Relativistic Heavy Ion Collider (RHIC), using an AC dipole to excite a single eigenmode. Besides the full treatment, a fast estimate of beta*, the beta function at the interaction point (IP), is provided, along with the phase advance between these BPMs. We also calculate and measure the waist of the beta function and the local optics

  10. Thermal, optical, and electrical engineering of an innovative tunable white LED light engine

    Science.gov (United States)

    Trivellin, Nicola; Meneghini, Matteo; Ferretti, Marco; Barbisan, Diego; Dal Lago, Matteo; Meneghesso, Gaudenzio; Zanoni, Enrico

    2014-02-01

    Color temperature, intensity and blue spectrum of the light affects the ganglion receptors in human brain stimulating the human nervous system. With this work we review different methods for obtaining tunable light emission spectra and propose an innovative white LED lighting system. By an in depth study of the thermal, electrical and optical characteristics of GaN and GaP based compound semiconductors for optoelectronics a specific tunable spectra has been designed. The proposed tunable white LED system is able to achieve high CRI (above 95) in a large CCT range (3000 - 5000K).

  11. Utilizing Near-IR Tunable Laser Absorption Spectroscopy to Study Detonation and Combustion Systems

    Science.gov (United States)

    2014-03-27

    A Hencken burner, Rotating Detonation Engine ( RDE ), and a detonation tube were studied using a Time-Devision Multiplexed Tunable Diode Laser...for the three systems. Velocity was calculated for the RDE system using the Doppler shift of the spectral lines. To perform the calculations necessary...however, the CH4 flame did not match as well. The exhaust of the RDE was studied at various equivalence ratios using a hydrogen-air mixture (H2-air

  12. Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems

    Science.gov (United States)

    Richards, Lance; Parker, Allen; Chan, Patrick

    2014-01-01

    The objective of this task is to investigate, develop, and demonstrate a low-cost swept lasing light source for NASA DFRC's fiber optics sensing system (FOSS) to perform structural health monitoring on current and future aerospace vehicles. This is the regular update of the Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems website.

  13. Direct determination of glucose, lactate and triglycerides in blood serum by a tunable quantum cascade laser-based mid-IR sensor

    Science.gov (United States)

    Brandstetter, M.; Volgger, L.; Genner, A.; Jungbauer, C.; Lendl, B.

    2013-02-01

    This work reports on a compact sensor for fast and reagent-free point-of-care determination of glucose, lactate and triglycerides in blood serum based on a tunable (1030-1230 cm-1) external-cavity quantum cascade laser (EC-QCL). For simple and robust operation a single beam set-up was designed and only thermoelectric cooling was used for the employed laser and detector. Full computer control of analysis including liquid handling and data analysis facilitated routine measurements. A high optical pathlength (>100 μm) is a prerequisite for robust measurements in clinical practice. Hence, the optimum optical pathlength for transmission measurements in aqueous solution was considered in theory and experiment. The experimentally determined maximum signal-to-noise ratio (SNR) was around 140 μm for the QCL blood sensor and around 50 μm for a standard FT-IR spectrometer employing a liquid nitrogen cooled mercury cadmium telluride (MCT) detector. A single absorption spectrum was used to calculate the analyte concentrations simultaneously by using a partial-least-squares (PLS) regression analysis. Glucose was determined in blood serum with a prediction error (RMSEP) of 6.9 mg/dl and triglycerides with an error of cross-validation (RMSECV) of 17.5 mg/dl in a set of 42 different patients. In spiked serum samples the lactate concentration could be determined with an RMSECV of 8.9 mg/dl.

  14. Piezo activated mode tracking system for widely tunable mode-hop-free external cavity mid-IR semiconductor lasers

    Science.gov (United States)

    Wysocki, Gerard (Inventor); Tittel, Frank K. (Inventor); Curl, Robert F. (Inventor)

    2010-01-01

    A widely tunable, mode-hop-free semiconductor laser operating in the mid-IR comprises a QCL laser chip having an effective QCL cavity length, a diffraction grating defining a grating angle and an external cavity length with respect to said chip, and means for controlling the QCL cavity length, the external cavity length, and the grating angle. The laser of claim 1 wherein said chip may be tuned over a range of frequencies even in the absence of an anti-reflective coating. The diffraction grating is controllably pivotable and translatable relative to said chip and the effective QCL cavity length can be adjusted by varying the injection current to the chip. The laser can be used for high resolution spectroscopic applications and multi species trace-gas detection. Mode-hopping is avoided by controlling the effective QCL cavity length, the external cavity length, and the grating angle so as to replicate a virtual pivot point.

  15. Fully tunable 360° microwave photonic phase shifter based on a single semiconductor optical amplifier.

    Science.gov (United States)

    Sancho, Juan; Lloret, Juan; Gasulla, Ivana; Sales, Salvador; Capmany, José

    2011-08-29

    A fully tunable microwave photonic phase shifter involving a single semiconductor optical amplifier (SOA) is proposed and demonstrated. 360° microwave phase shift has been achieved by tuning the carrier wavelength and the optical input power injected in an SOA while properly profiting from the dispersion feature of a conveniently designed notch filter. It is shown that the optical filter can be advantageously employed to switch between positive and negative microwave phase shifts. Numerical calculations corroborate the experimental results showing an excellent agreement.

  16. Tunable all-optical plasmonic rectifier in nanoscale metal-insulator-metal waveguides.

    Science.gov (United States)

    Xu, Yi; Wang, Xiaomeng; Deng, Haidong; Guo, Kangxian

    2014-10-15

    We propose a tunable all-optical plasmonic rectifier based on the nonlinear Fano resonance in a metal-insulator-metal plasmonic waveguide and cavities coupling system. We develop a theoretical model based on the temporal coupled-mode theory to study the device physics of the nanoscale rectifier. We further demonstrate via the finite difference time domain numerical experiment that our idea can be realized in a plasmonic system with an ultracompact size of ~120×800  nm². The tunable plasmonic rectifier could facilitate the all-optical signal processing in nanoscale.

  17. Magneto-Optic Fiber Gratings Useful for Dynamic Dispersion Management and Tunable Comb Filtering

    International Nuclear Information System (INIS)

    Bao-Jian, Wu; Xin, Lu; Kun, Qiu

    2010-01-01

    Intelligent control of dispersion management and tunable comb filtering in optical network applications can be performed by using magneto-optic fiber Bragg gratings (MFBGs). When a nonuniform magnetic field is applied to the MFBG with a constant grating period, the resulting grating response is equivalent to that of a conventional chirped grating. Under a linearly nonuniform magnetic field along the grating, a linear dispersion is achieved in the grating bandgap and the maximal dispersion slope can come to 1260 ps/nm 2 for a 10-mm-long fiber grating at 1550 nm window. Similarly, a Gaussian-apodizing sampled MFBG is also useful for magnetically tunable comb filtering, with potential application to clock recovery from return-to-zero optical signals and optical carrier tracking. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  18. Tunable optical analog to electromagnetically induced transparency in graphene-ring resonators system.

    Science.gov (United States)

    Wang, Yonghua; Xue, Chenyang; Zhang, Zengxing; Zheng, Hua; Zhang, Wendong; Yan, Shubin

    2016-12-12

    The analogue of electromagnetically induced transparency in optical ways has shown great potential in optical delay and quantum-information technology due to its flexible design and easy implementation. The chief drawback for these devices is the bad tunability. Here we demonstrate a tunable optical transparency system formed by graphene-silicon microrings which could control the transparent window by electro-optical means. The device consists of cascaded coupled ring resonators and a graphene/graphene capacitor which integrated on one of the rings. By tuning the Fermi level of the graphene sheets, we can modulate the round-trip ring loss so that the transparency window can be dynamically tuned. The results provide a new method for the manipulation and transmission of light in highly integrated optical circuits and quantum information storage devices.

  19. Thermal tunability of photonic bandgaps in liquid crystal infiltrated microstructured polymer optical fibers

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Wei, Lei; Alkeskjold, Thomas Tanggaard

    2009-01-01

    We demonstrate the photonic bandgap effect and the thermal tunability of bandgaps in microstructured polymer optical fibers infiltrated with liquid crystal. Two liquid crystals with opposite sign of the temperature gradient of the ordinary refractive index (E7 and MDA-00- 1444) are used to demons......We demonstrate the photonic bandgap effect and the thermal tunability of bandgaps in microstructured polymer optical fibers infiltrated with liquid crystal. Two liquid crystals with opposite sign of the temperature gradient of the ordinary refractive index (E7 and MDA-00- 1444) are used...... to demonstrate that both signs of the thermal tunability of the bandgaps are possible. The useful bandgaps are ultimately bounded to the visible range by the transparency window of the polymer....

  20. Acousto-Optic Tunable Filter Hyperspectral Microscope Imaging Method for Characterizing Spectra from Foodborne Pathogens.

    Science.gov (United States)

    Hyperspectral microscope imaging (HMI) method, which provides both spatial and spectral characteristics of samples, can be effective for foodborne pathogen detection. The acousto-optic tunable filter (AOTF)-based HMI method can be used to characterize spectral properties of biofilms formed by Salmon...

  1. Polarization independent polymer waveguide tunable receivers incorporating a micro-optic circulator

    Science.gov (United States)

    Wu, Xiaoping; Park, Tae-Hyun; Park, Su-Hyun; Seo, Jun-Kyu; Oh, Min-Cheol

    2018-06-01

    In order to simplify the receiver configuration in a wavelength division multiplexed optical fiber network, compact wavelength tunable filters have long been expected to be used as channel selectors. Bragg reflector inherently has the most suitable reflection spectrum for filtering a single wavelength from the densely multiplexed wavelength signal. Polymer has high thermo-optic coefficient and good thermal insulation property compared to the other optical waveguide materials such as silicon and silica materials. This can be used to broadly tune the reflection spectrum of Bragg reflector using a simple micro-heater. In this work, a micro-optic circulator component and a polymeric Bragg reflector device are assembled to produce a small form factor tunable receiver. Compared to the integrated-optical versions, the micro-optics are based on well-developed manufacturing processes and can achieve competitive production yields. The device exhibits high reflectivity with a flat top passband, and a polarization dependence of 0.06 nm achieved by virtue of the low birefringence of LFR polymer, which make a significant contribution to the implementation of polarization independent tunable receiver. The wavelength tuning range of 40 nm is demonstrated by using a bottom located heater with a groove for heat isolation.

  2. Tunable orbital angular momentum mode filter based on optical geometric transformation.

    Science.gov (United States)

    Huang, Hao; Ren, Yongxiong; Xie, Guodong; Yan, Yan; Yue, Yang; Ahmed, Nisar; Lavery, Martin P J; Padgett, Miles J; Dolinar, Sam; Tur, Moshe; Willner, Alan E

    2014-03-15

    We present a tunable mode filter for spatially multiplexed laser beams carrying orbital angular momentum (OAM). The filter comprises an optical geometric transformation-based OAM mode sorter and a spatial light modulator (SLM). The programmable SLM can selectively control the passing/blocking of each input OAM beam. We experimentally demonstrate tunable filtering of one or multiple OAM modes from four multiplexed input OAM modes with vortex charge of ℓ=-9, -4, +4, and +9. The measured output power suppression ratio of the propagated modes to the blocked modes exceeds 14.5 dB.

  3. Tunable all-optical devices based on liquid-filled photonic crystal fibers

    DEFF Research Database (Denmark)

    Rosberg, Christian Romer; Bennet, Francis; Neshev, Dragomir N.

    of discrete and nonlinear light propagation in extended two-dimensional periodic systems. We experimentally demonstrate strongly tunable beam diffraction in a triangular waveguide array created by infiltration of a high index liquid into the cladding holes of a standard PCF, and employ the thermal...... high-precision fabrication procedures, and provides high tunability and nonlinearity at moderate laser powers while taking advantage of a compact experimental setup. The increasingly broad range of PCF structures available could stimulate further efforts in applying them in discrete nonlinear optics...

  4. An optical technique to measure the frequency and mode emission of tunable lasers

    International Nuclear Information System (INIS)

    Marchetti, S.; Simili, R.

    1988-01-01

    To use mode tunable lasers it is necessary to measure the laser frequency and the mode emission. This problem is very important when waveguide lasers are used. Normally this information is obtained by a heterodyne technique, but there are some difficulties to perform this method in a large electrical noise environment, when pulsed of radiofrequency lasers are used. This laser information was obtained by using an alternative low-cost optical system. With this apparatus the cavity pulling was measured and an upper limit for the linewidth of a radiofrequency, high pressure, line and mode-tunable, CO 2 laser was roughly estimated

  5. Tunability of the FBG group delay through acousto-optic modulation

    Science.gov (United States)

    Marques, Carlos A. F.; Oliveira, Roberson A.; Pohl, Alexandre A. P.; Nogueira, Rogério N.

    2013-03-01

    A new method for fine control of the group delay of a fiber Bragg grating (FBG) is presented. It is based on an acoustic wave applied to the fiber. The standing acoustic wave imposes a periodic chirp to the uniform FBG. Tunability is obtained through adjustment of the intensity and/or frequency of the acoustic wave. A fast switching time of ∼17 μs was achieved. The experimental results were verified by theoretical simulation showing a good agreement between them. It can be used for different applications such as tunable narrow dispersion compensator for independent coarse wavelength division multiplexing (CWDM) channels or optical delay lines.

  6. Polarization-Insensitive Tunable Optical Filters based on Liquid Crystal Polarization Gratings

    Science.gov (United States)

    Nicolescu, Elena

    Tunable optical filters are widely used for a variety of applications including spectroscopy, optical communication networks, remote sensing, and biomedical imaging and diagnostics. All of these application areas can greatly benefit from improvements in the key characteristics of the tunable optical filters embedded in them. Some of these key parameters include peak transmittance, bandwidth, tuning range, and transition width. In recent years research efforts have also focused on miniaturizing tunable optical filters into physically small packages for compact portable spectroscopy and hyperspectral imaging applications such as real-time medical diagnostics and defense applications. However, it is important that miniaturization not have a detrimental effect on filter performance. The overarching theme of this dissertation is to explore novel configurations of Polarization Gratings (PGs) as simple, low-cost, polarization-insensitive alternatives to conventional optical filtering technologies for applications including hyperspectral imaging and telecommunications. We approach this goal from several directions with a combination of theory and experimental demonstration leading to, in our opinion, a significant contribution to the field. We present three classes of tunable optical filters, the first of which is an angle-filtering scheme where the stop-band wavelengths are redirected off axis and the passband is transmitted on-axis. This is achieved using a stacked configuration of polarization gratings of various thicknesses. To improve this class of filter, we also introduce a novel optical element, the Bilayer Polarization Grating, exhibiting unique optical properties and demonstrating complex anchoring conditions with high quality. The second class of optical filter is analogous to a Lyot filter, utilizing stacks of static or tunable waveplates sandwiched with polarizing elements. However, we introduce a new configuration using PGs and static waveplates to replace

  7. Characterization of tunable light source by optical parametric oscillator for high resolution spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J. W. [Ewha Womens Univ., Seoul (Korea); Rhee, B. G. [Sejong Univ., Seoul (Korea); Park, S. W. [Yonsei Univ., Seoul (Korea); Noh, J. W. [Inha Univ., Incheon (Korea)

    1998-04-01

    A tunable light source is developed by the optical parametric oscillator, which is very useful for a high resolution spectroscopy. The electronic structure of molecules and atoms can be examined by a proper coherent light source. Optical parametric oscillator provides light sources stable and widely tunable. In this work, the characteristics of the parametric optical generation are examined in the LiNbO{sub 3}. The theoretical analysis as well as the experimental measurement is performed. The pump laser is a second harmonic of Nd:YAG laser, and the parametric gain is measured. The characteristics of singly resonant oscillator and doubly resonant oscillator is studied as a function of temperature. It is found that 1mole% MgO:LiNbO{sub 3} crystal provides the tunability from 0.6{mu}m to 3.0{mu}m wavelength. Both the critical and noncritical phase matching are studied. The optical damage occurring in a congruent LiNbO{sub 3} crystal was not observed in 1mole% MgO:LiNbO{sub 3} crystal, opening a possibility for a high power optical parametric oscillation generation. The current work can be extended to an experiment employing the fundamental Nd:YAG as pump to provide a coherent light source for the study of molecular vibrations. 28 refs., 14 figs., 3 tabs. (Author)

  8. MID-IR LUMINOSITIES AND UV/OPTICAL STAR FORMATION RATES AT z < 1.4

    International Nuclear Information System (INIS)

    Salim, Samir; Dickinson, Mark; Michael Rich, R.; Charlot, Stephane; Lee, Janice C.; Schiminovich, David; Perez-Gonzalez, Pablo G.; Ashby, Matthew L. N.; Noeske, Kai; Papovich, Casey; Weiner, Benjamin J.; Faber, S. M.; Ivison, Rob J.; Frayer, David T.; Walton, Josiah M.; Chary, Ranga-Ram; Bundy, Kevin; Koekemoer, Anton M.

    2009-01-01

    Ultraviolet (UV) nonionizing continuum and mid-infrared (IR) emission constitute the basis of two widely used star formation (SF) indicators at intermediate and high redshifts. We study 2430 galaxies with z 10 -10 12 L sun ). We show that the IR luminosity can be estimated from the UV and optical photometry to within a factor of 2, implying that most z IR >10 11 L sun , yet with little current SF. For them a reasonable amount of dust absorption of stellar light (but presumably higher than in nearby early-type galaxies) is sufficient to produce the observed levels of IR, which includes a large contribution from intermediate and old stellar populations. In our sample, which contains very few ultraluminous IR galaxies, optical and X-ray active galactic nuclei do not contribute on average more than ∼50% to the mid-IR luminosity, and we see no evidence for a large population of 'IR excess' galaxies.

  9. Remote optically-tunable transimpedance amplifiers for quantum well diodes

    Energy Technology Data Exchange (ETDEWEB)

    Carraresi, L.; Landi, G.; Rocchi, S.; Vignoli, V

    1999-08-01

    In a previous paper we discussed the advantages in using linear optical transmission systems based on quantum well diodes in modern high energy physics experiments. In this paper, after a short summary of the quantum well theory, the electronics section of the above optical transmission system is presented. In particular the basic configuration of a transimpedance amplifier and the arrangement of an optical remote control system for the amplifier gain and bandwidth tuning are discussed.

  10. Remote optically-tunable transimpedance amplifiers for quantum well diodes

    International Nuclear Information System (INIS)

    Carraresi, L.; Landi, G.; Rocchi, S.; Vignoli, V.

    1999-01-01

    In a previous paper we discussed the advantages in using linear optical transmission systems based on quantum well diodes in modern high energy physics experiments. In this paper, after a short summary of the quantum well theory, the electronics section of the above optical transmission system is presented. In particular the basic configuration of a transimpedance amplifier and the arrangement of an optical remote control system for the amplifier gain and bandwidth tuning are discussed

  11. PEPSI, the High-Resolution Optical-IR Spectrograph for the LBT

    Science.gov (United States)

    Andersen, Michael; Strassmeier, Klaus; Hoffman, Axel; Woche, Manfred; Spano, Paolo

    PEPSI is a high resolution fibre feed optical-IR polarimetric echelle spectrograph for the Large Binocular Telescope (LBT). PEPSI utilizes the two 8.4m LBT apertures to simultaneously record four polarization states at a resolution of 120.000. The extension of the coverage towards the IR is mainly motivated by the larger Zeeman splitting of IR lines, which would allow to study weaker/fainter magnetic structures on stars. The two optical arms, which also have an integral light mode with R up to 300.000, are under construction, while the IR arm is being designed.

  12. Chromatic aberrations correction for imaging spectrometer based on acousto-optic tunable filter with two transducers.

    Science.gov (United States)

    Zhao, Huijie; Wang, Ziye; Jia, Guorui; Zhang, Ying; Xu, Zefu

    2017-10-02

    The acousto-optic tunable filter (AOTF) with wide wavelength range and high spectral resolution has long crystal and two transducers. A longer crystal length leads to a bigger chromatic focal shift and the double-transducer arrangement induces angular mutation in diffracted beam, which increase difficulty in longitudinal and lateral chromatic aberration correction respectively. In this study, the two chromatic aberrations are analyzed quantitatively based on an AOTF optical model and a novel catadioptric dual-path configuration is proposed to correct both the chromatic aberrations. The test results exhibit effectiveness of the optical configuration for this type of AOTF-based imaging spectrometer.

  13. Optical Pumping of the Electronic and Nuclear Spin of Single Charge-Tunable Quantum Dots

    Science.gov (United States)

    Bracker, A. S.; Stinaff, E. A.; Gammon, D.; Ware, M. E.; Tischler, J. G.; Shabaev, A.; Efros, Al. L.; Park, D.; Gershoni, D.; Korenev, V. L.; Merkulov, I. A.

    2005-02-01

    We present a comprehensive examination of optical pumping of spins in individual GaAs quantum dots as we change the net charge from positive to neutral to negative with a charge-tunable heterostructure. Negative photoluminescence polarization memory is enhanced by optical pumping of ground state electron spins, which we prove with the first measurements of the Hanle effect on an individual quantum dot. We use the Overhauser effect in a high longitudinal magnetic field to demonstrate efficient optical pumping of nuclear spins for all three charge states of the quantum dot.

  14. Metal-Mesh Optical Filter Technology for Mid IR, Far IR, and Submillimeter, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovative, high transmission band-pass filter technology proposed here is an improvement in multilayer metal-mesh filter design and manufacture for the far IR...

  15. Magnetic Nanoparticle-Assisted Tunable Optical Patterns from Spherical Cholesteric Liquid Crystal Bragg Reflectors

    OpenAIRE

    Lin, Yali; Yang, Yujie; Shan, Yuwei; Gong, Lingli; Chen, Jingzhi; Li, Sensen; Chen, Lujian

    2017-01-01

    Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these optical patterns with tunability, we fabricated spherical CLC Bragg reflectors in the shape of microshells by glass-capillary microfluidi...

  16. Moth eye-inspired anti-reflective surfaces for improved IR optical systems & visible LEDs fabricated with colloidal lithography and etching.

    Science.gov (United States)

    Chan, Lesley W; Morse, Daniel E; Gordon, Michael J

    2018-05-08

    Near- and sub-wavelength photonic structures are used by numerous organisms (e.g. insects, cephalopods, fish, birds) to create vivid and often dynamically-tunable colors, as well as create, manipulate, or capture light for vision, communication, crypsis, photosynthesis, and defense. This review introduces the physics of moth eye (ME)-like, biomimetic nanostructures and discusses their application to reduce optical losses and improve efficiency of various optoelectronic devices, including photodetectors, photovoltaics, imagers, and light emitting diodes. Light-matter interactions at structured and heterogeneous surfaces over different length scales are discussed, as are the various methods used to create ME-inspired surfaces. Special interest is placed on a simple, scalable, and tunable method, namely colloidal lithography with plasma dry etching, to fabricate ME-inspired nanostructures in a vast suite of materials. Anti-reflective surfaces and coatings for IR devices and enhancing light extraction from visible light emitting diodes are highlighted.

  17. Tunable light source for fiber optic lighting applications

    Science.gov (United States)

    Narendran, Nadarajah; Bierman, Andrew; Finney, Mark J.; Edwards, Ian K.

    1997-09-01

    This paper examines the possibility of tuning the lamp spectrum to compensate for color distortions in fiber optic lighting systems. Because most optical fibers have strong absorption in the blue and red wavelength regions, white light entering and propagating down an optical fiber suffers varied amounts of attenuation as a function of wavelength. As a result, the light exiting the optical fiber has a greenish tint that the lighting design community considers undesirable in interior lighting applications. HID lamps are commonly used for the light source in this industry. Certain classes of HID lamps tend to shift in color when their operating position or the input voltage to the lamp is changed. An experimental study is being conducted to characterize the color shift properties of a small HID lamp as a function of tilt and input voltage. The study also examines the possibility of exploiting this color shift to compensate for the color distortions caused by optical fibers. The details of the experiment and the results are presented in this manuscript.

  18. Fibre-Optic IR-Spectroscopy for Biomedical Diagnostics

    OpenAIRE

    Bindig, Uwe; Gersonde, Ingo; Meinke, Martina; Becker, Yukiyo; Müller, Gerhard

    2003-01-01

    The use of microscopy is a valuable means of gaining vital information for medical diagnostics. Due to a number of recent technological developments advances have been made in IR microscopy and in particular, rapid detection methods. Microscopic examination methods usually involve sampling followed by a method of sample purification or preparation. The advantages of the IR analytical method are that it is based on a direct, non‒destructive measurement of sample material and that the resulting...

  19. Thermally and optically tunable lasing properties from dye-doped holographic polymer dispersed liquid crystal in capillaries

    Science.gov (United States)

    Chen, Maozhou; Dai, Haitao; Wang, Dongshuo; Yang, Yue; Luo, Dan; Zhang, Xiaodong; Liu, Changlong

    2018-03-01

    In this paper, we investigated tunable lasing properties from the dye-doped holographic polymer dispersed liquid crystal (HPDLC) gratings in capillaries with thermal and optical manners. The thermally tunable range of the lasing from the dye-doped HPDLC reached 8.60 nm with the temperature ranging from 23 °C to 50 °C. The optically tunable laser emission was achieved by doping azo-dye in HPDLC. The transition of azo-dye from trans- to cis-state could induce the reorientation of LC molecules after UV light irradiation, which resulted in the variation of refractive index contrast of LC-rich/polymer-rich layer in HPDLC. Experimentally, the emission wavelength of lasing showed a blueshift (about 2 nm) coupled with decreasing output intensities. The tunable laser based on HPDLC may enable more applications in laser displays, optical communication, biosensors, etc.

  20. Application-specific specialty microstructured optical fibers for mid-IR and THz photonics (Invited)

    DEFF Research Database (Denmark)

    Pal, Bishnu P.; Barh, Ajanta; Varshney, Ravi K.

    2016-01-01

    A review of several of our designed specialty microstructured optical fibers (MOFs) for mid-IR and THz generation and transmission including high power transmission is presented. Extensive results on performance of the designed MOFs are described....

  1. Graphene-based fine-tunable optical delay line for optical beamforming in phased-array antennas.

    Science.gov (United States)

    Tatoli, Teresa; Conteduca, Donato; Dell'Olio, Francesco; Ciminelli, Caterina; Armenise, Mario N

    2016-06-01

    The design of an integrated graphene-based fine-tunable optical delay line on silicon nitride for optical beamforming in phased-array antennas is reported. A high value of the optical delay time (τg=920  ps) together with a compact footprint (4.15  mm2) and optical loss graphene-based Mach-Zehnder interferometer switches and two vertically stacked microring resonators between which a graphene capacitor is placed. The tuning range is obtained by varying the value of the voltage applied to the graphene electrodes, which controls the optical path of the light propagation and therefore the delay time. The graphene provides a faster reconfigurable time and low values of energy dissipation. Such significant advantages, together with a negligible beam-squint effect, allow us to overcome the limitations of conventional RF beamformers. A highly efficient fine-tunable optical delay line for the beamsteering of 20 radiating elements up to ±20° in the azimuth direction of a tile in a phased-array antenna of an X-band synthetic aperture radar has been designed.

  2. Optical parameters of the tunable Bragg reflectors in squid.

    Science.gov (United States)

    Ghoshal, Amitabh; Demartini, Daniel G; Eck, Elizabeth; Morse, Daniel E

    2013-08-06

    Cephalopods (e.g. octopus, squid and cuttlefish) dynamically tune the colour and brightness of their skin for camouflage and communication using specialized skin cells called iridocytes. We use high-resolution microspectrophotometry to investigate individual tunable Bragg structures (consisting of alternating reflectin protein-containing, high-refractive index lamellae and low-refractive index inter-lamellar spaces) in live and chemically fixed iridocytes of the California market squid, Doryteuthis opalescens. This subcellular, single-stack microspectrophotometry allows for spectral normalization, permitting use of a transfer-matrix model of Bragg reflectance to calculate all the parameters of the Bragg stack-the refractive indices, dimensions and numbers of the lamellae and inter-lamellar spaces. Results of the fitting analyses show that eight or nine pairs of low- and high-index layers typically contribute to the observed reflectivity in live cells, whereas six or seven pairs of low- and high-index layers typically contribute to the reflectivity in chemically fixed cells. The reflectin-containing, high-index lamellae of live cells have a refractive index proportional to the peak reflectivity, with an average of 1.405 ± 0.012 and a maximum around 1.44, while the reflectin-containing lamellae in fixed tissue have a refractive index of 1.413 ± 0.015 suggesting a slight increase of refractive index in the process of fixation. As expected, incremental changes in refractive index contribute to the greatest incremental changes in reflectivity for those Bragg stacks with the most layers. The excursions in dimensions required to tune the measured reflected wavelength from 675 (red) to 425 nm (blue) are a decrease from ca 150 to 80 nm for the high-index lamellae and from ca 120 to 50 nm for the low-index inter-lamellar spaces. Fixation-induced dimensional changes also are quantified, leading us to suggest that further microspectrophotometric analyses of this iridocyte

  3. Electrically tunable coherent optical absorption in graphene with ion gel.

    Science.gov (United States)

    Thareja, Vrinda; Kang, Ju-Hyung; Yuan, Hongtao; Milaninia, Kaveh M; Hwang, Harold Y; Cui, Yi; Kik, Pieter G; Brongersma, Mark L

    2015-03-11

    We demonstrate electrical control over coherent optical absorption in a graphene-based Salisbury screen consisting of a single layer of graphene placed in close proximity to a gold back reflector. The screen was designed to enhance light absorption at a target wavelength of 3.2 μm by using a 600 nm-thick, nonabsorbing silica spacer layer. An ionic gel layer placed on top of the screen was used to electrically gate the charge density in the graphene layer. Spectroscopic reflectance measurements were performed in situ as a function of gate bias. The changes in the reflectance spectra were analyzed using a Fresnel based transfer matrix model in which graphene was treated as an infinitesimally thin sheet with a conductivity given by the Kubo formula. The analysis reveals that a careful choice of the ionic gel layer thickness can lead to optical absorption enhancements of up to 5.5 times for the Salisbury screen compared to a suspended sheet of graphene. In addition to these absorption enhancements, we demonstrate very large electrically induced changes in the optical absorption of graphene of ∼3.3% per volt, the highest attained so far in a device that features an atomically thick active layer. This is attributable in part to the more effective gating achieved with the ion gel over the conventional dielectric back gates and partially by achieving a desirable coherent absorption effect linked to the presence of the thin ion gel that boosts the absorption by 40%.

  4. Tunable all-optical photonic crystal channel drop filter for DWDM systems

    Science.gov (United States)

    Habibiyan, H.; Ghafoori-Fard, H.; Rostami, A.

    2009-06-01

    In this paper we propose a tunable channel drop filter in a two-dimensional photonic crystal, based on coupled-cavity waveguides with alternating small and large defects and an electromagnetically induced transparency phenomenon. By utilizing this phenomenon a narrower linewidth is obtained and also the frequency of the dropped signal becomes tunable. Simulation results show that the proposed filter is suitable for dense wavelength-division multiplexing (DWDM) systems with 0.8 nm channel spacing. Using this novel component, two ultrasmall eight-channel double-sided and single-sided demultiplexers are introduced. The properties of these devices are investigated using the finite-difference time-domain method. For the single-sided device, transmission loss is 1.5 ± 0.5 dB, the cross-talk level between adjacent channels is better than -18 dB and the average 3 dB optical passband is 0.36 nm. Using planar silicon-on-insulator technology, the physical area for the single-sided component is 700 µm2 and for the double-sided component is 575 µm2. To the best of our knowledge, these are the smallest all-optical demultiplexers with this spectral resolution reported to date. Malfunction of the proposed device due to fabrication errors is modeled and its tunable characteristic is demonstrated.

  5. Tunable Optical Tweezers for Wavelength-dependent Measurements

    Science.gov (United States)

    2012-04-23

    have been studied in an optical levitation scheme over short laser wavelength ranges20 and for dye-loaded di- electric particles.21 In the first case...M. Block, IEEE J. Sel. Top. Quantum Electron. 2, 1066 (1996). 7K. Dholakia, W. M. Lee, L. Paterson, M. P. MacDonald, I. Andreev, P. Mthunzi, C. T. A...Brown, R. F. Marchington, and A. C. Riches, IEEE J. Sel. Top. Quantum Electron. 13, 1646 (2007). 8K. Dholakia, M. P. MacDonald, P. Zemanek, and T

  6. Tunable optical frequency comb enabled scalable and cost-effective multiuser orthogonal frequency-division multiple access passive optical network with source-free optical network units.

    Science.gov (United States)

    Chen, Chen; Zhang, Chongfu; Liu, Deming; Qiu, Kun; Liu, Shuang

    2012-10-01

    We propose and experimentally demonstrate a multiuser orthogonal frequency-division multiple access passive optical network (OFDMA-PON) with source-free optical network units (ONUs), enabled by tunable optical frequency comb generation technology. By cascading a phase modulator (PM) and an intensity modulator and dynamically controlling the peak-to-peak voltage of a PM driven signal, a tunable optical frequency comb source can be generated. It is utilized to assist the configuration of a multiple source-free ONUs enhanced OFDMA-PON where simultaneous and interference-free multiuser upstream transmission over a single wavelength can be efficiently supported. The proposed multiuser OFDMA-PON is scalable and cost effective, and its feasibility is successfully verified by experiment.

  7. MEOS Microsatellite Earth Observation using Miniature Integrated-Optic IR Spectrometers

    Science.gov (United States)

    Kruzelecky, Roman

    ±0.1 kPa from measurements of the 0.76 mm O2 A band with 0.02 nm resolution and will contain an imager for surface observations at 25×40 m2 resolution within a 100×160 km2 view. This will assist with cloud detection, measurement geolocation and determination of land-cover status. The MEOS payload encompasses groundbreaking innovation in miniaturized infrared (IR) spectrometers based on MPBC's patented technologies (US 7,034,935 B1) for high performance guided-wave spectrometers. The guided-wave spectrometer integration provides an order of magnitude reduction in the mass and volume relative to traditional bulk-optic spectrometers, with a net mass under 2 kg, while also providing significant performance advantages; including an optically immersed master grating for minimal aberrations, robust optical alignment using a low-loss dielectric IR waveguide, and simultaneous broad-band spectral acquisition. Output integrated optics facilitate miniaturization of the detector pixels for high measurement sensitivity. Patented, binary-coded smart signal processing of IR detector arrays iteratively compensates for both random and non-random noise to yield over 60 dB of signal dynamic range. The following paper discusses the breadboarding of the miniature high-resolution FP-IOSPEC spectrometer in support of the MEOS payload requirements. This innovatively combines a tunable Fabry-Perot filter with a guided-wave spectrometer to simultaneously provide multiple microchannels with a spectral resolution to below 0.03 nm FWHM, broad spectral range of operation from 1500 to 2450 nm, and a large optical input aperture. The spectrometer miniaturization is a significant and original advance that facilitates the use of multiple dedicated spectrometers on the same microsat platform to allow simultaneous and coordinated measurements as described above. Acknowledgements The financial assistance of the Canadian Space Agency is greatly appreciated. The constructive suggestions of Guennadi

  8. Tunable band gap and optical properties of surface functionalized Sc2C monolayer

    International Nuclear Information System (INIS)

    Wang Shun; Du Yu-Lei; Liao Wen-He

    2017-01-01

    Using the density functional theory, we have investigated the electronic and optical properties of two-dimensional Sc 2 C monolayer with OH, F, or O chemical groups. The electronic structures reveal that the functionalized Sc 2 C monolayers are semiconductors with a band gap of 0.44–1.55 eV. The band gap dependent optical parameters, like dielectric function, absorption coefficients, reflectivity, loss function, and refraction index were also calculated for photon energy up to 20 eV. At the low-energy region, each optical parameter shifts to red, and the peak increases obviously with the increase of the energy gap. Consequently, Sc 2 C monolayer with a tunable band gap by changing the type of surface chemical groups is a promising 2D material for optoelectronic devices. (paper)

  9. Sub–100-nm metafluorophores with digitally tunable optical properties self-assembled from DNA

    Science.gov (United States)

    Woehrstein, Johannes B.; Strauss, Maximilian T.; Ong, Luvena L.; Wei, Bryan; Zhang, David Y.; Jungmann, Ralf; Yin, Peng

    2017-01-01

    Fluorescence microscopy allows specific target detection down to the level of single molecules and has become an enabling tool in biological research. To transduce the biological information to an imageable signal, we have developed a variety of fluorescent probes, such as organic dyes or fluorescent proteins with different colors. Despite their success, a limitation on constructing small fluorescent probes is the lack of a general framework to achieve precise and programmable control of critical optical properties, such as color and brightness. To address this challenge, we introduce metafluorophores, which are constructed as DNA nanostructure–based fluorescent probes with digitally tunable optical properties. Each metafluorophore is composed of multiple organic fluorophores, organized in a spatially controlled fashion in a compact sub–100-nm architecture using a DNA nanostructure scaffold. Using DNA origami with a size of 90 × 60 nm2, substantially smaller than the optical diffraction limit, we constructed small fluorescent probes with digitally tunable brightness, color, and photostability and demonstrated a palette of 124 virtual colors. Using these probes as fluorescent barcodes, we implemented an assay for multiplexed quantification of nucleic acids. Additionally, we demonstrated the triggered in situ self-assembly of fluorescent DNA nanostructures with prescribed brightness upon initial hybridization to a nucleic acid target. PMID:28691083

  10. Electro-optic tunable multi-channel filter in two-dimensional ferroelectric photonic crystals

    International Nuclear Information System (INIS)

    Fu, Yulan; Zhang, Jiaxiang; Hu, Xiaoyong; Gong, Qihuang

    2010-01-01

    An electro-optic tunable multi-channel filter is presented, which is based on a two-dimensional ferroelectric photonic crystal made of barium titanate. The filtering properties of the photonic crystal filter can be tuned by an applied voltage or by adjusting the structural parameters. The channel shifts about 30 nm under excitation of an applied voltage of 54.8 V. The influences of the structural disorders caused by the perturbations in the radius or the position of air holes on the filtering properties are also analyzed

  11. CW seeded optical parametric amplifier providing wavelength and pulse duration tunable nearly transform limited pulses.

    Science.gov (United States)

    Hädrich, S; Gottschall, T; Rothhardt, J; Limpert, J; Tünnermann, A

    2010-02-01

    An optical parametric amplifier that delivers nearly transform limited pulses is presented. The center wavelength of these pulses can be tuned between 993 nm and 1070 nm and, at the same time, the pulse duration is varied between 206 fs and 650 fs. At the shortest pulse duration the pulse energy was increased up to 7.2 microJ at 50 kHz repetition rate. Variation of the wavelength is achieved by applying a tunable cw seed while the pulse duration can be varied via altering the pump pulse duration. This scheme offers superior flexibility and scaling possibilities.

  12. Protection of Passive Optical Networks by Using Ring Topology and Tunable Splitters

    Directory of Open Access Journals (Sweden)

    Pavel Lafata

    2013-01-01

    Full Text Available This article proposes an innovative method for protecting of passive optical networks (PONs, especially the central optical unit – optical line termination (OLT. PON networks are typically used in modern high-speed access networks, but there are also several specific applications, such as in business, army or science sector, which require a complex protection and backup system against failures and malfunctions. A standard tree or star topologies, which are usually used for PON networks, are significantly vulnerable mainly against the malfunctions and failures of OLT unit or feeder optical cable. The method proposed in this paper is focused on forming PON network with ring topology using passive optical splitters. The main idea is based on the possibility of placing both OLT units (primary and secondary on the opposite sides of the ring, which can potentially increase the resistance of network. This method is described in the article and scenarios and calculations using symmetric or tunable asymmetric passive optical splitters are included as well.

  13. Ring-shaped active mode-locked tunable laser using quantum-dot semiconductor optical amplifier

    Science.gov (United States)

    Zhang, Mingxiao; Wang, Yongjun; Liu, Xinyu

    2018-03-01

    In this paper, a lot of simulations has been done for ring-shaped active mode-locked lasers with quantum-dot semiconductor optical amplifier (QD-SOA). Based on the simulation model of QD-SOA, we discussed about the influence towards mode-locked waveform frequency and pulse caused by QD-SOA maximum mode peak gain, active layer loss coefficient, bias current, incident light pulse, fiber nonlinear coefficient. In the meantime, we also take the tunable performance of the laser into consideration. Results showed QD-SOA a better performance than original semiconductor optical amplifier (SOA) in recovery time, line width, and nonlinear coefficients, which makes it possible to output a locked-mode impulse that has a higher impulse power, narrower impulse width as well as the phase is more easily controlled. After a lot of simulations, this laser can realize a 20GHz better locked-mode output pulse after 200 loops, where the power is above 17.5mW, impulse width is less than 2.7ps, moreover, the tunable wavelength range is between 1540nm-1580nm.

  14. Highly Stable Wideband Microwave Extraction by Synchronizing Widely Tunable Optoelectronic Oscillator with Optical Frequency Comb

    Science.gov (United States)

    Hou, D.; Xie, X. P.; Zhang, Y. L.; Wu, J. T.; Chen, Z. Y.; Zhao, J. Y.

    2013-12-01

    Optical frequency combs (OFCs), based on mode-locked lasers (MLLs), have attracted considerable attention in many fields over recent years. Among the applications of OFCs, one of the most challenging works is the extraction of a highly stable microwave with low phase noise. Many synchronisation schemes have been exploited to synchronise an electronic oscillator with the pulse train from a MLL, helping to extract an ultra-stable microwave. Here, we demonstrate novel wideband microwave extraction from a stable OFC by synchronising a single widely tunable optoelectronic oscillator (OEO) with an OFC at different harmonic frequencies, using an optical phase detection technique. The tunable range of the proposed microwave extraction extends from 2 GHz to 4 GHz, and in a long-term synchronisation experiment over 12 hours, the proposed synchronisation scheme provided a rms timing drift of 18 fs and frequency instabilities at 1.2 × 10-15/1 s and 2.2 × 10-18/10000 s.

  15. A broadly tunable autocorrelator for ultra-short, ultra-high power infrared optical pulses

    Energy Technology Data Exchange (ETDEWEB)

    Szarmes, E.B.; Madey, J.M.J. [Duke Univ., Durham, NC (United States)

    1995-12-31

    We describe the design of a crossed-beam, optical autocorrelator that uses an uncoated, birefringent beamsplitter to split a linearly polarized incident pulse into two orthogonally polarized pulses, and a Type II, SHG crystal to generate the intensity autocorrelation function. The uncoated beamsplitter accommodates extremely broad tunability while precluding any temporal distortion of ultrashort optical pulses at the dielectric interface, and the specific design provides efficient operation between 1 {mu}m and 4 {mu}m. Furthermore, the use of Type II SHG completely eliminates any single-beam doubling, so the autocorrelator can be operated at very shallow crossed-beam angles without generating a background pedestal. The autocorrelator has been constructed and installed in the Mark III laboratory at Duke University as a broadband diagnostic for ongoing compression experiments on the chirped-pulse FEL.

  16. Tunable femtosecond laser in the visible range with an intracavity frequency-doubled optical parametric oscillator

    International Nuclear Information System (INIS)

    Zhu Jiang-Feng; Xu Liang; Lin Qing-Feng; Zhong Xin; Han Hai-Nian; Wei Zhi-Yi

    2013-01-01

    We demonstrated experimentally a synchronously pumped intracavity frequency-doubled femtosecond optical parametric oscillator (OPO) using a periodically-poled lithium niobate (PPLN) as the nonlinear material in combination with a lithium triborate (LBO) as the doubling crystal. A Kerr-lens-mode-locked (KLM) Ti:sapphire oscillator at the wavelength of 790 nm was used as the pump source, which was capable of generating pulses with a duration as short as 117 fs. A tunable femtosecond laser covering the 624–672 nm range was realized by conveniently adjusting the OPO cavity length. A maximum average output power of 260 mW in the visible range was obtained at the pump power of 2.2 W, with a typical pulse duration of 205 fs assuming a sech 2 pulse profile. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  17. Electrically tunable Brillouin fiber laser based on a metal-coated single-mode optical fiber

    Directory of Open Access Journals (Sweden)

    S.M. Popov

    Full Text Available We explore tunability of the Brillouin fiber laser employing Joule heating. For this purpose, 10-m-length of a metal-coated single-mode optical cavity fiber has been directly included into an electrical circuit, like a conductor wire. With the current up to ∼3.5 A the laser tuning is demonstrated over a spectrum range of ∼400 MHz. The observed laser line broadening up to ∼2 MHz is explained by frequency drift and mode-hoping in the laser caused by thermal noise. Keywords: Brillouin fiber laser, Metal-coated optical fiber, Laser tuning, Fiber sensors

  18. Investigation of optical pump on dielectric tunability in PZT/PT thin film by THz spectroscopy.

    Science.gov (United States)

    Ji, Jie; Luo, Chunya; Rao, Yunkun; Ling, Furi; Yao, Jianquan

    2016-07-11

    The dielectric spectra of single-layer PbTiO3 (PT), single-layer PbZrxTi1-xO3 (PZT) and multilayer PZT/PT thin films under an external optical field were investigated at room temperature by time-domain terahertz (THz) spectroscopy. Results showed that the real part of permittivity increased upon application of an external optical field, which could be interpreted as hardening of the soft mode and increasing of the damping coefficient and oscillator strength. Furthermore, the central mode was observed in the three films. Among the dielectric property of the three thin films studied, the tunability of the PZT/PT superlattice was the largest.

  19. A tunable continuous wave (CW) and short-pulse optical source for THz brain imaging applications

    International Nuclear Information System (INIS)

    Bakopoulos, P; Karanasiou, I; Zakynthinos, P; Uzunoglu, N; Avramopoulos, H; Pleros, N

    2009-01-01

    We demonstrate recent advances toward the development of a novel 2D THz imaging system for brain imaging applications both at the macroscopic and at the bimolecular level. A frequency-synthesized THz source based on difference frequency generation between optical wavelengths is presented, utilizing supercontinuum generation in a highly nonlinear optical fiber with subsequent spectral carving by means of a fiber Fabry–Perot filter. Experimental results confirm the successful generation of THz radiation in the range of 0.2–2 THz, verifying the enhanced frequency tunability properties of the proposed system. Finally, the roadmap toward capturing functional brain information by exploiting THz imaging technologies is discussed, outlining the unique advantages offered by THz frequencies and their complementarity with existing brain imaging techniques

  20. Optical modeling of the Jefferson Lab IR Demo FEL

    International Nuclear Information System (INIS)

    Neil, G.; Benson, S.; Shinn, M.; Davidson, P.; Kloppel, P.

    1997-01-01

    The Thomas Jefferson National Accelerator Facility (formerly known as CEBAF) has embarked on the construction of a 1 kW free-electron laser operating initially at 3 microns that is designed for laser-material interaction experiments and to explore the feasibility of scaling the system in power and wavelength for industrial and Navy defense applications. The superconducting radio-frequency linac, and single-pass transport which accelerates the beam from injector to wiggler, followed by energy-recovery deceleration to a dump. The electron and optical beam time structure in the design consists of a train of pecosecond pulses at a 37.425 MHz pulse repetition rate. The initial optical configuration is a conventional near-concentric resonator with transmissive outcoupling. Future upgrades of the system will increase the power and shorten the operating wavelength, and utilize a more advanced resonator system capable of scaling to high powers. The optical system of the laser has been mode led using the GLAD code by using a Beer's-law region to mimic the FEL interaction. Effects such as mirror heating have been calculated and compared with analytical treatments. The magnitude of the distorium for several materials and wavelengths has been estimated. The advantages as well as the limitations of this approach are discussed

  1. IR Optics Measurement with Linear Coupling's Action-Angle Parameterization

    CERN Document Server

    Luo, Yun; Pilat, Fulvia Caterina; Satogata, Todd; Trbojevic, Dejan

    2005-01-01

    The interaction region (IP) optics are measured with the two DX/BPMs close to the IPs at the Relativistic Heavy Ion Collider (RHIC). The beta functions at IP are measured with the two eigenmodes' phase advances between the two BPMs. And the beta waists are also determined through the beta functions at the two BPMs. The coupling parameters at the IPs are also given through the linear coupling's action-angle parameterization. All the experimental data are taken during the driving oscillations with the AC dipole. The methods to do these measurements are discussed. And the measurement results during the beta*

  2. Numerical optimization of quasi-optical mode converter for frequency step-tunable gyrotron

    International Nuclear Information System (INIS)

    Drumm, O.

    2002-08-01

    This work concentrates on the design of a quasi-optical mode converter for a frequency step-tunable gyrotron. Special attention is paid to the optimization of the conversion and forming of the exited wave of different frequencies inside the resonator. The investigations were part of the HGF-strategy-fonds-project ''Optimization of Tokamak Operation with controlled ECRH-Deposition''. In the resonator of the gyrotron modes can be exited at frequencies between 105 and 140 GHz. With the designed converter the desired field distribution at the output window for all frequencies will be approximately obtained. The newly gained knowledge and invented synthesis methods are applied to this practical example and verified. In this work, the waveguide antenna and the mirror system of the quasi-optical mode converter are presented separately from each other. At the beginning the synthesis of the aperture antenna for a frequency step-tunable design of the Vlasov-type as well as the Denisov-type is considered. As a conclusion of the investigation, the important parameters for the design of all antennas are summarized and the frequency behavior is compared. In the second part of this work new broadband design methods for the synthesis of the mirror surface are presented. These mirrors make an optimal wave forming for all frequencies equally possible. Therefore new quality criteria are introduced for the broadband evaluation of the mirror. Afterwards the surface is varied until the criteria reach an optimum. For the numerical optimization, in this work the gradient method and the extended Katsenelenbaum-Semenov algorithm are invented and applied. The efficient realization of the described algorithms on a computer is the significant point. The theoretical background of the presented methods for the synthesis of a mirror system is based on the general solution of the Helmholtz equation. Due to this, these methods can be utilized in other fields outside the microwave applications in

  3. Simultaneous IR and optical light curves of 2A0311-227

    International Nuclear Information System (INIS)

    Bailey, J.; Hough, J.H.; Axon, D.J.

    1983-01-01

    It is reported that the optical and IR flickering of the AM Herculis type binary 2A0311 - 227 are highly correlated indicating that in this object the dominant source of cyclotron radiation at both wavelengths is the same accretion column. (U.K.)

  4. Integrated tunable quantum-dot laser for optical coherence tomography in the 1.7 μm wavelength region

    NARCIS (Netherlands)

    Tilma, B.W.; Jiao, Y.; Kotani, J.; Smalbrugge, B.; Ambrosius, H.P.M.M.; Thijs, P.J.A.; Leijtens, X.J.M.; Nötzel, R.; Smit, M.K.; Bente, E.A.J.M.

    2012-01-01

    In this paper we present the design and characterization of a monolithically integrated tunable laser for optical coherence tomography in medicine. This laser is the first monolithic photonic integrated circuit containing quantum-dot amplifiers, phase modulators and passive components. We

  5. Tunable and reconfigurable microwave filter by use of a Bragg-grating-based acousto-optic superlattice modulator.

    Science.gov (United States)

    Delgado-Pinar, M; Mora, J; Díez, A; Andrés, M V; Ortega, B; Capmany, J

    2005-01-01

    We present an all-optical novel configuration for implementing multitap transversal filters by use of a broadband source sliced by fiber Bragg grating arrays generated by propagating an acoustic wave along a strong uniform fiber Bragg grating. The tunability and reconfigurability of the microwave filter are demonstrated.

  6. Tunable electronic, electrical and optical properties of graphene oxide sheets by ion irradiation

    Science.gov (United States)

    Jayalakshmi, G.; Saravanan, K.; Panigrahi, B. K.; Sundaravel, B.; Gupta, Mukul

    2018-05-01

    The tunable electronic, electrical and optical properties of graphene oxide (GO) sheets were investigated using a controlled reduction by 500 keV Ar+-ion irradiation. The carbon to oxygen ratio of the GO sheets upon the ion beam reduction has been estimated using resonant Rutherford backscattering spectrometry analyses and its effect on the electrical and optical properties of GO sheets has been studied using sheet resistance measurements and photoluminescence (PL) measurements. The restoration of sp 2-hybridized carbon atoms within the sp 3 matrix is found to be increases with increasing the Ar+-ion fluences as evident from Fourier transform infrared, and x-ray absorption near-edge structure measurements. The decrease in the number of disorder-induced local density of states (LDOSs) within the π-π* gap upon the reduction causes the shifting of PL emission from near infra-red to blue region and decreases the sheet resistance. The improved electrical and optical properties of GO sheets were correlated to the decrease in the number of LDOSs within the π-π* gap. Our experimental investigations suggest ion beam irradiation is one of an effective approaches to reduce GO to RGO and to tailor its electronic, electrical and optical properties.

  7. Characterization of PDMS samples with variation of its synthesis parameters for tunable optics applications

    Science.gov (United States)

    Marquez-Garcia, Josimar; Cruz-Félix, Angel S.; Santiago-Alvarado, Agustin; González-García, Jorge

    2017-09-01

    Nowadays the elastomer known as polydimethylsiloxane (PDMS, Sylgard 184), due to its physical properties, low cost and easy handle, have become a frequently used material for the elaboration of optical components such as: variable focal length liquid lenses, optical waveguides, solid elastic lenses, etc. In recent years, we have been working in the characterization of this material for applications in visual sciences; in this work, we describe the elaboration of PDMSmade samples, also, we present physical and optical properties of the samples by varying its synthesis parameters such as base: curing agent ratio, and both, curing time and temperature. In the case of mechanical properties, tensile and compression tests were carried out through a universal testing machine to obtain the respective stress-strain curves, and to obtain information regarding its optical properties, UV-vis spectroscopy is applied to the samples to obtain transmittance and absorbance curves. Index of refraction variation was obtained through an Abbe refractometer. Results from the characterization will determine the proper synthesis parameters for the elaboration of tunable refractive surfaces for potential applications in robotics.

  8. Optically tunable spin-exchange energy at donor:acceptor interfaces in organic solar cells

    International Nuclear Information System (INIS)

    Li, Mingxing; Wang, Hongfeng; He, Lei; Zang, Huidong; Xu, Hengxing; Hu, Bin

    2014-01-01

    Spin-exchange energy is a critical parameter in controlling spin-dependent optic, electronic, and magnetic properties in organic materials. This article reports optically tunable spin-exchange energy by studying the line-shape characteristics in magnetic field effect of photocurrent developed from intermolecular charge-transfer states based on donor:acceptor (P3HT:PCBM) system. Specifically, we divide magnetic field effect of photocurrent into hyperfine (at low field   10 mT) regimes. We observe that increasing photoexcitation intensity can lead to a significant line-shape narrowing in magnetic field effect of photocurrent occurring at the spin-exchange regime. We analyze that the line-shape characteristics is essentially determined by the changing rate of magnetic field-dependent singlet/triplet ratio when a magnetic field perturbs the singlet-triplet transition through spin mixing. Based on our analysis, the line-shape narrowing results indicate that the spin-exchange energy at D:A interfaces can be optically changed by changing photoexcitation intensity through the interactions between intermolecular charge-transfer states. Therefore, our experimental results demonstrate an optical approach to change the spin-exchange energy through the interactions between intermolecular charge-transfer states at donor:acceptor interface in organic materials.

  9. First quantitative measurements by IR spectroscopy of dioxins and furans by means of broadly tunable quantum cascade lasers

    International Nuclear Information System (INIS)

    Siciliani de Cumis, M; D’Amato, F; Viciani, S; Patrizi, B; Foggi, P; Galea, C L

    2013-01-01

    We demonstrate the possibility of a quantitative analysis of the concentration of several dioxins and furans, among the most toxic ones, by only using infrared absorption laser spectroscopy. Two broadly tunable quantum cascade lasers, emitting in the mid-infrared, have been used to measure the absorption spectra of dioxins and furans, dissolved in CCl 4 , in direct absorption mode. The minimum detectable concentrations are inferred by analyzing diluted samples. A comparison between this technique and standard Fourier transform spectroscopy has been carried out and an analysis of future perspectives is reported. (paper)

  10. Tunable optical nonreciprocity and a phonon-photon router in an optomechanical system with coupled mechanical and optical modes

    Science.gov (United States)

    Li, Guolong; Xiao, Xiao; Li, Yong; Wang, Xiaoguang

    2018-02-01

    We propose a multimode optomechanical system to realize tunable optical nonreciprocity that has the prospect of making an optical diode for information technology. The proposed model consists of two subsystems, each of which contains two optical cavities, injected with a classical field and a quantum signal via a 50:50 beam splitter, and a mechanical oscillator, coupled to both cavities via optomechanical coupling. Meanwhile two cavities and an oscillator in a subsystem are respectively coupled to their corresponding cavities and an oscillator in the other subsystem. Our scheme yields nonreciprocal effects at different frequencies with opposite directions, but each effective linear optomechanical coupling can be controlled by an independent classical one-frequency pump. With this setup one is able to apply quantum states with large fluctuations, which extends the scope of applicable quantum states, and exploit the independence of paths. Moreover, the optimal frequencies for nonreciprocal effects can be controlled by adjusting the relevant parameters. We also exhibit the path switching of two directions, from a mechanical input to two optical output channels, via tuning the signal frequency. In experiment, the considered scheme can be tuned to reach small damping rates of the oscillators relative to those of the cavities, which is more practical and requires less power than in previous schemes.

  11. Tunable Microcavity-Stabilized Quantum Cascade Laser for Mid-IR High-Resolution Spectroscopy and Sensing

    Directory of Open Access Journals (Sweden)

    Simone Borri

    2016-02-01

    Full Text Available The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF2 microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line.

  12. Tunable Microcavity-Stabilized Quantum Cascade Laser for Mid-IR High-Resolution Spectroscopy and Sensing.

    Science.gov (United States)

    Borri, Simone; Siciliani de Cumis, Mario; Insero, Giacomo; Bartalini, Saverio; Cancio Pastor, Pablo; Mazzotti, Davide; Galli, Iacopo; Giusfredi, Giovanni; Santambrogio, Gabriele; Savchenkov, Anatoliy; Eliyahu, Danny; Ilchenko, Vladimir; Akikusa, Naota; Matsko, Andrey; Maleki, Lute; De Natale, Paolo

    2016-02-17

    The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF₂ microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line.

  13. Polarization field gradient effects in inhomogeneous metal-ferroelectric bilayers: Optical response and band gap tunability

    Energy Technology Data Exchange (ETDEWEB)

    Vivas C, H., E-mail: hvivasc@unal.edu.co [Grupo de las Propiedades Opticas de los Materiales (POM), Departamento de Fisica, Universidad Nacional de Colombia, Sede Manizales, A.A. 127 (Colombia); Vargas-Hernandez, C. [Grupo de las Propiedades Opticas de los Materiales (POM), Departamento de Fisica, Universidad Nacional de Colombia, Sede Manizales, A.A. 127 (Colombia)

    2012-06-15

    Optical constants, reflectivity response and direct band gap energy (E{sub g}{sup d}) were calculated and simulated by developing an electrodynamic-based model for a three medium system, namely vacuum/ferroelectric film/metallic substrate. Depolarization effects due to the contact between the metallic substrate and the FE film, as well as the spatially dependent profile of the dielectric susceptibility {epsilon}(z) enter into the formalism by adapting the phenomenological Landau-Ginzburg-Devonshire theory (LGD). Absorption coefficient is obtained from the Lambert-Beer-Bouguer (LBB) approximation and the direct band gap energy as a function of the characteristic length is calculated by using the general Tauc power law. Numerical simulations lead to range of values for tunable E{sub g}{sup d} from 2.6 to 2.8 eV for characteristic lengths up to 30% the thickness of the film, in concordance with recent reports.

  14. Tunable optical setup with high flexibility for spectrally resolved coherent anti-Stokes Raman scattering microscopy

    International Nuclear Information System (INIS)

    Bergner, G; Akimov, D; Bartelt, H; Dietzek, B; Popp, J; Schlücker, S

    2011-01-01

    A simplified setup for coherent anti-Stokes Raman scattering (CARS) microscopy is introduced, which allows for recording CARS images with 30 cm -1 excitation bandwidth for probing Raman bands between 500 and 900 cm -1 with minimal requirements for alignment. The experimental arrangement is based on electronic switching between CARS images recorded at different Raman resonances by combining a photonic crystal fiber (PCF) as broadband light source and an acousto-optical programmable dispersive filter (AOPDF) as tunable wavelength filter. Such spatial light modulator enables selection of a narrow-band spectrum to yield high vibrational contrast and hence chemical contrast in the resultant CARS images. Furthermore, an experimental approach to reconstruct spectral information from CARS image contrast is introduced

  15. Design and optical analyses of an arrayed microfluidic tunable prism panel for enhancing solar energy collection

    International Nuclear Information System (INIS)

    Narasimhan, Vinayak; Jiang, Dongyue; Park, Sung-Yong

    2016-01-01

    Highlights: • We present an arrayed tunable prism panel enabling wide tracking and high solar concentration. • A microfluidic technology allows a low-cost, lightweight and precise solar tracking system. • Our prism panel enables high solar concentration up to 2032× factor. • Various liquid prism configurations (stacked prism arrays) and optical materials are considered. • Their impacts on solar beam steering, reflection losses and beam concentration are studied. - Abstract: We present the design and optical analyses of an arrayed microfluidic tunable prism panel that enables wide solar tracking and high solar concentration while minimizing energy loss. Each of the liquid prism modules is implemented by a microfluidic (i.e. non-mechanical) technology based on electrowetting for adaptive solar beam steering. Therefore the proposed platform offers a low-cost, lightweight and precise solar tracking system while obviating the need for bulky and heavy mechanical moving parts essentially required for a conventional motor-driven solar tracker. In this paper, various liquid prism configurations in terms of design (single, double, triple and quad-stacked prism arrays) as well as optical materials are considered and their impact on optical performance aspects such as solar beam steering, reflection losses and beam concentration is studied. Our system is able to achieve a wide solar tracking covering the whole-day movement of the Sun and a reflection loss below 4.4% with a Rayleigh’s film for a quad-stacked prism configuration. Furthermore, an arrayed prism panel is proposed to increase the aperture area and thus allows for the collection of large amounts of sunlight. Our simulation study based on the optical design software, ZEMAX, indicates that the prism panel is capable of high solar concentration up to 2032× factor even without conventional solar tracking devices. We also deal with dispersion characteristics of the materials and their corresponding effect on

  16. Double tungsten coil atomic absorption spectrometer based on an acousto-optic tunable filter

    International Nuclear Information System (INIS)

    Jora, M.Z.; Nóbrega, J.A.; Rohwedder, J.J.R.; Pasquini, C.

    2015-01-01

    An atomic absorption spectrometer based on a quartz acousto-optic tunable filter (AOTF) monochromator operating in the 271–453 nm range, is described. The instrument was tailored to study the formation and evolution of electrothermal atomic cloud induced either by one or two tungsten coils. The spectrometer also includes a fast response programmable photomultiplier module for data acquisition, and a power supply capable of driving two parallel tungsten coils independently. The atomization cell herein described was manufactured in PTFE and presents a new design with reduced size. Synchronization between the instant of power delivering to start the atomization process and the detection was achieved, allowing for monitoring the atomization and thermal events synchronously and in real time. Absorption signals can be sampled at a rate of a few milliseconds, compatible with the fast phenomena that occur with electrothermal metallic atomizers. The instrument performance was preliminarily evaluated by monitoring the absorption of radiation of atomic clouds produced by standard solutions containing chromium or lead. Its quantitative performance was evaluated by using Cr aqueous solutions, resulting in detection limits as low as 0.24 μg L −1 , and a relative standard deviation of 3%. - Highlights: • The use of an Acousto-Optic Tunable Filter (AOTF) as monochromator element in WC AAS is presented for the first time. • The system includes the possibility of using one or two parallel coils. • We propose a new atomization cell design, manufactured on PTFE with reduced size. • The temperature of the coils and the atomic clouds of Pb and Cr were observed synchronously with high temporal resolution

  17. Light-enabled reversible self-assembly and tunable optical properties of stable hairy nanoparticles

    Science.gov (United States)

    Chen, Yihuang; Wang, Zewei; He, Yanjie; Yoon, Young Jun; Jung, Jaehan; Zhang, Guangzhao; Lin, Zhiqun

    2018-02-01

    The ability to dynamically organize functional nanoparticles (NPs) via the use of environmental triggers (temperature, pH, light, or solvent polarity) opens up important perspectives for rapid and convenient construction of a rich variety of complex assemblies and materials with new structures and functionalities. Here, we report an unconventional strategy for crafting stable hairy NPs with light-enabled reversible and reliable self-assembly and tunable optical properties. Central to our strategy is to judiciously design amphiphilic star-like diblock copolymers comprising inner hydrophilic blocks and outer hydrophobic photoresponsive blocks as nanoreactors to direct the synthesis of monodisperse plasmonic NPs intimately and permanently capped with photoresponsive polymers. The size and shape of hairy NPs can be precisely tailored by modulating the length of inner hydrophilic block of star-like diblock copolymers. The perpetual anchoring of photoresponsive polymers on the NP surface renders the attractive feature of self-assembly and disassembly of NPs on demand using light of different wavelengths, as revealed by tunable surface plasmon resonance absorption of NPs and the reversible transformation of NPs between their dispersed and aggregated states. The dye encapsulation/release studies manifested that such photoresponsive NPs may be exploited as smart guest molecule nanocarriers. By extension, the star-like block copolymer strategy enables the crafting of a family of stable stimuli-responsive NPs (e.g., temperature- or pH-sensitive polymer-capped magnetic, ferroelectric, upconversion, or semiconducting NPs) and their assemblies for fundamental research in self-assembly and crystallization kinetics of NPs as well as potential applications in optics, optoelectronics, magnetic technologies, sensory materials and devices, catalysis, nanotechnology, and biotechnology.

  18. Tunable and broadband microwave frequency combs based on a semiconductor laser with incoherent optical feedback

    International Nuclear Information System (INIS)

    Zhao Mao-Rong; Wu Zheng-Mao; Deng Tao; Zhou Zhen-Li; Xia Guang-Qiong

    2015-01-01

    Based on a semiconductor laser (SL) with incoherent optical feedback, a novel all-optical scheme for generating tunable and broadband microwave frequency combs (MFCs) is proposed and investigated numerically. The results show that, under suitable operation parameters, the SL with incoherent optical feedback can be driven to operate at a regular pulsing state, and the generated MFCs have bandwidths broader than 40 GHz within a 10 dB amplitude variation. For a fixed bias current, the line spacing (or repetition frequency) of the MFCs can be easily tuned by varying the feedback delay time and the feedback strength, and the tuning range of the line spacing increases with the increase in the bias current. The linewidth of the MFCs is sensitive to the variation of the feedback delay time and the feedback strength, and a linewidth of tens of KHz can be achieved through finely adjusting the feedback delay time and the feedback strength. In addition, mappings of amplitude variation, repetition frequency, and linewidth of MFCs in the parameter space of the feedback delay time and the feedback strength are presented. (paper)

  19. Generation of continuously tunable, 5-12 {mu}m radiation by difference frequency mixing of output waves of a KTP optical parametric oscillator in a ZnGeP{sub 2} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Haidar, S [Research Institute of Electrical Communication (RIEC), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai-shi 980-8577 (Japan); Miyamoto, K [Research Institute of Electrical Communication (RIEC), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai-shi 980-8577 (Japan); Ito, H [Research Institute of Electrical Communication (RIEC), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai-shi 980-8577 (Japan)

    2004-12-07

    Signal and idlers waves obtained from a Nd : YAG laser pumped KTP optical parametric oscillator (OPO) are difference frequency mixed in a ZnGeP{sub 2} (ZGP) crystal to generate radiation in the mid-infrared. The KTP OPO is operated in the type-II phase matching mode, and the extraordinary and ordinary waves are tunable from 1.76 {mu}m to 2.36 {mu}m and from 2.61 {mu}m to 1.90 {mu}m, respectively. The orthogonally polarized waves are difference frequency mixed in a ZGP crystal to generate mid-IR radiation tunable from 5 to 12 {mu}m.

  20. Multilayered phantoms with tunable optical properties for a better understanding of light/tissue interactions

    Science.gov (United States)

    Roig, Blandine; Koenig, Anne; Perraut, François; Piot, Olivier; Vignoud, Séverine; Lavaud, Jonathan; Manfait, Michel; Dinten, Jean-Marc

    2015-03-01

    Light/tissue interactions, like diffuse reflectance, endogenous fluorescence and Raman scattering, are a powerful means for providing skin diagnosis. Instrument calibration is an important step. We thus developed multilayered phantoms for calibration of optical systems. These phantoms mimic the optical properties of biological tissues such as skin. Our final objective is to better understand light/tissue interactions especially in the case of confocal Raman spectroscopy. The phantom preparation procedure is described, including the employed method to obtain a stratified object. PDMS was chosen as the bulk material. TiO2 was used as light scattering agent. Dye and ink were adopted to mimic, respectively, oxy-hemoglobin and melanin absorption spectra. By varying the amount of the incorporated components, we created a material with tunable optical properties. Monolayer and multilayered phantoms were designed to allow several characterization methods. Among them, we can name: X-ray tomography for structural information; Diffuse Reflectance Spectroscopy (DRS) with a homemade fibered bundle system for optical characterization; and Raman depth profiling with a commercial confocal Raman microscope for structural information and for our final objective. For each technique, the obtained results are presented and correlated when possible. A few words are said on our final objective. Raman depth profiles of the multilayered phantoms are distorted by elastic scattering. The signal attenuation through each single layer is directly dependent on its own scattering property. Therefore, determining the optical properties, obtained here with DRS, is crucial to properly correct Raman depth profiles. Thus, it would be permitted to consider quantitative studies on skin for drug permeation follow-up or hydration assessment, for instance.

  1. Red-IR stimulated luminescence in K-feldspar: Single or multiple trap origin?

    DEFF Research Database (Denmark)

    Andersen, Martin Thalbitzer; Jain, Mayank; Tidemand-Lichtenberg, Peter

    2012-01-01

    We investigate on the origins of the infra-red stimulated luminescence (IRSL) signals in 3 potassium feldspars based on IR-red spectroscopy (700–1050 nm) using a fiber-coupled tunable Ti:Sapphire laser, in combination with different thermal and optical (pre)treatments of the samples. We also...

  2. 2.5 TW, two-cycle IR laser pulses via frequency domain optical parametric amplification.

    Science.gov (United States)

    Gruson, V; Ernotte, G; Lassonde, P; Laramée, A; Bionta, M R; Chaker, M; Di Mauro, L; Corkum, P B; Ibrahim, H; Schmidt, B E; Legaré, F

    2017-10-30

    Broadband optical parametric amplification in the IR region has reached a new milestone through the use of a non-collinear Frequency domain Optical Parametric Amplification system. We report a laser source delivering 11.6 fs pulses with 30 mJ of energy at a central wavelength of 1.8 μm at 10 Hz repetition rate corresponding to a peak power of 2.5 TW. The peak power scaling is accompanied by a pulse shortening of about 20% upon amplification due to the spectral reshaping with higher gain in the spectral wings. This source paves the way for high flux soft X-ray pulses and IR-driven laser wakefield acceleration.

  3. Electronically tunable femtosecond all-fiber optical parametric oscillator for multi-photon microscopy

    Science.gov (United States)

    Hellwig, Tim; Brinkmann, Maximilian; Fallnich, Carsten

    2018-02-01

    We present a femtosecond fiber-based optical parametric oscillator (FOPO) for multiphoton microscopy with wavelength tuning by electronic repetition rate tuning in combination with a dispersive filter in the FOPO cavity. The all-spliced, all-fiber FOPO cavity is based on polarization-maintaining fibers and a broadband output coupler, allowing to get access to the resonant signal pulses as well as the idler pulses simultaneously. The system was pumped by a gain-switched fiber-coupled laser diode emitting pulses at a central wavelength of 1030 nm and an electronically tunable repetition frequency of about 2 MHz. The pump pulses were amplified in an Ytterbium fiber amplifier system with a pulse duration after amplification of 13 ps. Tuning of the idler (1140 nm - 1300 nm) and signal wavelengths (850 nm - 940 nm) was achieved by changing the repetition frequency of the pump laser by about 4 kHz. The generated signal pulses reached a pulse energy of up to 9.2 nJ at 920 nm and were spectrally broadened to about 6 nm in the FOPO by a combination of self-phase and cross-phase modulation. We showed external compression of the idler pulses at 920 nm to about 430 fs and appleid them to two-photon excitation microscopy with green fluorescent dyes. The presented system constitutes an important step towards a fully fiber-integrated all-electronically tunable and, thereby, programmable light source and already embodies a versatile and flexible light source for applications, e.g., for smart microscopy.

  4. Fabrication of Au/graphene oxide/Ag sandwich structure thin film and its tunable energetics and tailorable optical properties

    Directory of Open Access Journals (Sweden)

    Ruijin Hong

    2017-01-01

    Full Text Available Au/graphene oxide/Ag sandwich structure thin film was fabricated. The effects of graphene oxide (GO and bimetal on the structure and optical properties of metal silver films were investigated by X-ray diffraction (XRD, optical absorption, and Raman intensity measurements, respectively. Compared to silver thin film, Au/graphene oxide/Ag sandwich structure composite thin films were observed with wider optical absorption peak and enhanced absorption intensity. The Raman signal for Rhodamine B molecules based on the Au/graphene oxide/Ag sandwich nanostructure substrate were obviously enhanced due to the bimetal layer and GO layer with tunable absorption intensity and fluorescence quenching effects.

  5. Spectral characterization in deep UV of an improved imaging KDP acousto-optic tunable filter

    International Nuclear Information System (INIS)

    Gupta, Neelam; Voloshinov, Vitaly

    2014-01-01

    Recently, we developed a number of high quality noncollinear acousto-optic tunable filter (AOTF) cells in different birefringent materials with UV imaging capability. Cells based on a single crystal of KDP (potassium dihydrophosphate) had the best transmission efficiency and the optical throughput needed to acquire high quality spectral images at wavelengths above 220 nm. One of the main limitations of these imaging filters was their small angular aperture in air, limited to about 1.0°. In this paper, we describe an improved imaging KDP AOTF operating from the deep UV to the visible region of the spectrum. The linear and angular apertures of the new filter are 10 × 10 mm 2 and 1.8°, respectively. The spectral tuning range is 205–430 nm with a 60 cm −1 spectral resolution. We describe the filter and present experimental results on imaging using both a broadband source and a number of light emitting diodes (LEDs) in the UV, and include the measured spectra of these LEDs obtained with a collinear SiO 2 filter-based spectrometer operating above 255 nm. (paper)

  6. Magnetic Nanoparticle-Assisted Tunable Optical Patterns from Spherical Cholesteric Liquid Crystal Bragg Reflectors

    Directory of Open Access Journals (Sweden)

    Yali Lin

    2017-11-01

    Full Text Available Cholesteric liquid crystals (CLCs exhibit selective Bragg reflections of circularly polarized (CP light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC structures. To endow these optical patterns with tunability, we fabricated spherical CLC Bragg reflectors in the shape of microshells by glass-capillary microfluidics. Water-soluble magnetofluid with Fe3O4 nanoparticles incorporated in the inner aqueous core of CLC shells is responsible for the non-invasive transportable capability. With the aid of an external magnetic field, the reflection interactions between neighboring microshells and microdroplets were identified by varying the mutual distance in a group of magnetically transportable and unmovable spherical CLC structures. The temperature-dependent optical reflection patterns were investigated in close-packed hexagonal arrangements of seven CLC microdroplets and microshells with inverse helicity handedness. Moreover, we demonstrated that the magnetic field-assisted assembly of microshells array into geometric figures of uppercase English letters “L” and “C” was successfully achieved. We hope that these findings can provide good application prospects for security pattern designs.

  7. Magnetic Nanoparticle-Assisted Tunable Optical Patterns from Spherical Cholesteric Liquid Crystal Bragg Reflectors.

    Science.gov (United States)

    Lin, Yali; Yang, Yujie; Shan, Yuwei; Gong, Lingli; Chen, Jingzhi; Li, Sensen; Chen, Lujian

    2017-11-08

    Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these optical patterns with tunability, we fabricated spherical CLC Bragg reflectors in the shape of microshells by glass-capillary microfluidics. Water-soluble magnetofluid with Fe₃O₄ nanoparticles incorporated in the inner aqueous core of CLC shells is responsible for the non-invasive transportable capability. With the aid of an external magnetic field, the reflection interactions between neighboring microshells and microdroplets were identified by varying the mutual distance in a group of magnetically transportable and unmovable spherical CLC structures. The temperature-dependent optical reflection patterns were investigated in close-packed hexagonal arrangements of seven CLC microdroplets and microshells with inverse helicity handedness. Moreover, we demonstrated that the magnetic field-assisted assembly of microshells array into geometric figures of uppercase English letters "L" and "C" was successfully achieved. We hope that these findings can provide good application prospects for security pattern designs.

  8. Optical and electrical properties of structured multilayer with tunable transparency rate

    International Nuclear Information System (INIS)

    Bou, Adrien; Torchio, Philippe; Barakel, Damien; Guillou, Aurélie; Thoulon, Pierre-Yves; Ricci, Marc; Ayachi, Boubakeur

    2015-01-01

    An experimental study has been carried out on structured multilayer with tunable transparency rate. In this paper, we present the optical and electrical characterization of an oxide | metal | oxide structured electrode manufactured by e-beam deposition and patterned by a lift-off process. The obtained samples are made of grids with different geometrical parameters that lead to varying surface coverage rate on glass. The electrical and optical parameters of SnO x |Ag|SnO x grids are investigated to determine the efficiency, sustainability and limitations of such structures. A linear relationship between the transmittance of the electrodes and the increase of the surface coverage rate is obtained. Coupled to an optimization process, we are able to define a high transparency in a chosen spectral range. Electrical results show a relative stability of the resistivity from 2.9   ×   10   −  4  Ω.cm for an as-grown electrode to 5.6   ×   10   −  4  Ω.cm for a structured electrode with a surface coverage rate of 59%. (paper)

  9. Tunable optical response at the plasmon-polariton frequency in dielectric-graphene-metamaterial systems

    Science.gov (United States)

    Calvo-Velasco, D. M.; Porras-Montenegro, N.

    2018-04-01

    By using the scattering matrix formalism, it is studied the optical properties of one dimensional photonic crystals made of multiple layers of dielectric and uniaxial anisotropic single negative electric metamaterial with Drude type responses, with inclusions of graphene in between the dielectric-dielectric interfaces (DGMPC). The transmission spectra for transverse electric (TE) and magnetic (TM) polarization are presented as a function of the incidence angle, the graphene chemical potential, and the metamaterial plasma frequencies. It is found for the TM polarization the tunability of the DGMPC optical response with the graphene chemical potential, which can be observed by means of transmission or reflexion bands around the metamaterial plasmon-polariton frequency, with bandwidths depending on both the incidence angle and the metamaterial plasma frequency. Also, the transmission band is observed when losses in the metamaterial slabs are considered for finite systems. The conditions for the appearance of these bands are shown analytically. We consider this work contributes to open new possibilities to the design of photonic devices with DGMPCs.

  10. Spectral shaping of an all-fiber torsional acousto-optic tunable filter.

    Science.gov (United States)

    Ko, Jeakwon; Lee, Kwang Jo; Kim, Byoung Yoon

    2014-12-20

    Spectral shaping of an all-fiber torsional acousto-optic (AO) tunable filter is studied. The technique is based on the axial modulation of AO coupling strength along a highly birefringent optical fiber, which is achieved by tailoring the outer diameter of the fiber along its propagation axis. Two kinds of filter spectral shaping schemes-Gaussian apodization and matched filtering with triple resonance peaks-are proposed and numerically investigated under realistic experimental conditions: at the 50-cm-long AO interaction length of the fiber and at half of the original fiber diameter as the minimum thickness of the tailored fiber section. The results show that the highest peak of sidelobe spectra in filter transmission is suppressed from 11.64% to 0.54% via Gaussian modulation of the AO coupling coefficient (κ). Matched filtering with triple resonance peaks operating with a single radio frequency signal is also achieved by cosine modulation of κ, of which the modulation period determines the spectral distance between two satellite peaks located in both wings of the main resonance peak. The splitting of two satellite peaks in the filter spectra reaches 48.2 nm while the modulation period varies from 7.7 to 50 cm. The overall peak power of two satellite resonances is calculated to be 22% of the main resonance power. The results confirm the validity and practicality of our approach, and we predict robust and stable operation of the designed all-fiber torsional AO filters.

  11. Tunable Diode Laser Atomic Absorption Spectroscopy for Detection of Potassium under Optically Thick Conditions.

    Science.gov (United States)

    Qu, Zhechao; Steinvall, Erik; Ghorbani, Ramin; Schmidt, Florian M

    2016-04-05

    Potassium (K) is an important element related to ash and fine-particle formation in biomass combustion processes. In situ measurements of gaseous atomic potassium, K(g), using robust optical absorption techniques can provide valuable insight into the K chemistry. However, for typical parts per billion K(g) concentrations in biomass flames and reactor gases, the product of atomic line strength and absorption path length can give rise to such high absorbance that the sample becomes opaque around the transition line center. We present a tunable diode laser atomic absorption spectroscopy (TDLAAS) methodology that enables accurate, calibration-free species quantification even under optically thick conditions, given that Beer-Lambert's law is valid. Analyte concentration and collisional line shape broadening are simultaneously determined by a least-squares fit of simulated to measured absorption profiles. Method validation measurements of K(g) concentrations in saturated potassium hydroxide vapor in the temperature range 950-1200 K showed excellent agreement with equilibrium calculations, and a dynamic range from 40 pptv cm to 40 ppmv cm. The applicability of the compact TDLAAS sensor is demonstrated by real-time detection of K(g) concentrations close to biomass pellets during atmospheric combustion in a laboratory reactor.

  12. Tunable optical properties of graphene oxide by tailoring the oxygen functionalities using infrared irradiation

    International Nuclear Information System (INIS)

    Maiti, R; Ray, S K; Midya, A; Narayana, C

    2014-01-01

    The modification of individual oxygen functional groups and the resultant optical properties of a graphene oxide suspension were investigated using a controlled photothermal reduction by infrared irradiation. The evolution of the structural and optical characteristics of GO suspensions was obtained from Raman spectra, x-ray photoelectron spectroscopy, optical absorption, and steady state and time-resolved photoluminescence spectroscopy. The results suggest the gradual restoration of sp 2 clusters within the sp 3 matrix with an increase of the reduction time and power density. The yellow-red emission (∼610 nm) originated from the defect-assisted localized states in GO due to epoxy/hydroxyl (C-O/-OH) functional groups and that of the blue emission (∼500 nm) was ascribed to the carbonyl (C=O)-assisted localized electronic states. With an increase in the reduction time and IR power density, the intensity of the yellow-red emission was found to decrease, with the blue emission being prominent. These experimental findings open up a new dimension for controlling the optical absorption and emission properties of graphene oxide by tailoring the oxygen functional groups, which may lead to the potential application of graphene-based optoelectronic devices. (paper)

  13. Near-diffraction-limited and low-haze electro-optical tunable liquid crystal lens with floating electrodes.

    Science.gov (United States)

    Li, Liwei; Bryant, Doug; Van Heugten, Tony; Bos, Philip J

    2013-04-08

    A near-diffraction-limited, low-haze and tunable liquid crystal (LC) lens is presented. Building on an understanding of the key factors that have limited the performance of lenses based on liquid crystals, we show a simple design whose optical quality is similar to a high quality glass lens. It uses 'floating' electrodes to provide a smooth, controllable applied potential profile across the aperture to manage the phase profile.

  14. Evaluation of MidIR fibre optic reflectance: Detection limit, reproducibility and binary mixture discrimination

    Science.gov (United States)

    Sessa, Clarimma; Bagán, Héctor; García, José Francisco

    2013-11-01

    MidIR fibre optic reflectance (MidIR-FORS) is a promising analytical technique in the field of science conservation, especially because it is non-destructive. Another advantage of MidIR-FORS is that the obtained information is representative, as a large amount of spectral data can be collected. Although the technique has a high potential and is almost routinely applied, its quality parameters have not been thoroughly studied in the specific application of analysis of artistic materials. The objective of this study is to evaluate the instrumental capabilities of MidIR-FORS for the analysis of artwork materials in terms of detection limit, reproducibility, and mixture characterisation. The study has been focused on oil easel painting and several paints of known composition have been analysed. Paint layers include blue pigments not only because of their important role along art history, but also because their physical and spectroscopic characteristics allow a better evaluation of the MidIR-FORS capabilities. The results of the analysis indicate that MidIR-FORS supplies a signal affected by different factors, such as the optical, morphological and physical properties of the surface, in addition to the composition of materials analysed. Consequently, the detection limits established are relatively high for artistic objects (Prussian blue - PB 2.1-6.5%; Phthalocyanine blue - Pht 6.3-10.2%; synthetic Ultramarine blue - UM 12.1%) and may therefore lead to an incomplete description of the artwork. Reproducibility of the technique over time and across surface has been determined. The results show that the major sources of dispersion are the heterogeneity of the pigments distribution, physical features, and band shape distortions. The total dispersion is around 4% for the most intense bands (oil) and increases up to 26% when weak or overlapped bands are considered (PB, Pht, UM). The application of different pre-treatments (cutoff of fibres absorption, Savizky-Golay smoothing

  15. Optimization of thermochromic VO2-based structures with tunable thermal emissivity

    International Nuclear Information System (INIS)

    Li Voti, R.; Larciprete, M.C.; Leahu, G.L.; Bertolotti, M.; Sibilia, C.

    2013-01-01

    In this paper we design and simulate VO 2 /metal multilayers to obtain a large tunability of the thermal emissivity of IR filters in the typical MWIR window of many infrared cameras. The multilayer structure is optimized to realise a low-emissivity filter at high temperatures useful for military purposes. The values of tunability found for VO 2 /metal multilayers are larger than the value for a single thick layer of VO 2 . Innovative SiO 2 /VO 2 synthetic opals are also investigated to enhance the optical tunability by combining the properties of a 3D periodic structure and the specific optical properties of vanadium dioxide.

  16. Thermally Resilient, Broadband Optical Absorber from UV to IR Derived from Carbon Nanostructures

    Science.gov (United States)

    Kaul, Anupama B.; Coles, James B.

    2012-01-01

    Optical absorber coatings have been developed from carbon-based paints, metal blacks, or glassy carbon. However, such materials are not truly black and have poor absorption characteristics at longer wavelengths. The blackness of such coatings is important to increase the accuracy of calibration targets used in radiometric imaging spectrometers since blackbody cavities are prohibitively large in size. Such coatings are also useful potentially for thermal detectors, where a broadband absorber is desired. Au-black has been a commonly used broadband optical absorber, but it is very fragile and can easily be damaged by heat and mechanical vibration. An optically efficient, thermally rugged absorber could also be beneficial for thermal solar cell applications for energy harnessing, particularly in the 350-2,500 nm spectral window. It has been demonstrated that arrays of vertically oriented carbon nanotubes (CNTs), specifically multi-walled-carbon- nanotubes (MWCNTs), are an exceptional optical absorber over a broad range of wavelengths well into the infrared (IR). The reflectance of such arrays is 100x lower compared to conventional black materials, such as Au black in the spectral window of 350-2,500 nm. Total hemispherical measurements revealed a reflectance of approximately equal to 1.7% at lambda approximately equal to 1 micrometer, and at longer wavelengths into the infrared (IR), the specular reflectance was approximately equal to 2.4% at lambda approximately equal to 7 micrometers. The previously synthesized CNTs for optical absorber applications were formed using water-assisted thermal chemical vapor deposition (CVD), which yields CNT lengths in excess of 100's of microns. Vertical alignment, deemed to be a critical feature in enabling the high optical absorption from CNT arrays, occurs primarily via the crowding effect with thermal CVD synthesized CNTs, which is generally not effective in aligning CNTs with lengths less than 10 m. Here it has been shown that the

  17. Composition and optical properties tunability of hydrogenated silicon carbonitride thin films deposited by reactive magnetron sputtering

    Science.gov (United States)

    Bachar, A.; Bousquet, A.; Mehdi, H.; Monier, G.; Robert-Goumet, C.; Thomas, L.; Belmahi, M.; Goullet, A.; Sauvage, T.; Tomasella, E.

    2018-06-01

    Radiofrequency reactive magnetron sputtering was used to deposit hydrogenated amorphous silicon carbonitride (a-SiCxNy:H) at 400 °C by sputtering a silicon target under CH4 and N2 reactive gas mixture. Rutherford backscattering spectrometry revealed that the change of reactive gases flow rate (the ratio R = FN2/(FN2+FCH4)) induced a smooth chemical composition tunability from a silicon carbide-like film for R = 0 to a silicon nitride-like one at R = 1 with a large area of silicon carbonitrides between the two regions. The deconvolution of Fourier Transform InfraRed and X-ray photoelectron spectroscopy spectrum highlighted a shift of the chemical environment of the deposited films corresponding to the changes seen by RBS. The consequence of these observations is that a control of refractive index in the range of [1.9-2.5] at λ = 633 nm and optical bandgap in the range [2 eV-3.8 eV] have been obtained which induces that these coatings can be used as antireflective coatings in silicon photovoltaic cells.

  18. An acousto-optic tunable filter enhanced CO{sub 2} lidar atmospheric monitor

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, L.H.; Suhre, D.R.; Mani, S.S. [and others

    1996-12-31

    The atmospheric monitor conceptual design is based on a pulsed CO{sub 2} laser. The narrow laser lines provide high spectral selectivity in the 9-11 {mu}m region, within the 8-14 {mu}m ``fingerprint`` region where most large molecules have unique spectral absorption signatures. Laser power has been chosen so that topological objects, e.g., trees or buildings, as far as 4 km can be used as backreflectors, but the laser intensity is sufficiently low that the laser beam is eye-safe. Time-of-flight measurements give the distance to the topological reflector. The lidar system is augmented with an acousto-optic tunable filter (AOTF) which measures the thermal emission spectra from 3 to 14 {mu}m with a 3 cm{sup -1} passband. Sensitivity to narrow emission lines is enhanced by derivative spectroscopy in which the passband of the AOTF is dithered via the rf drive. Path-averaged concentrations are determined from the emission intensity and laser- determined range.

  19. An acousto-optic tunable filter enhanced CO2 lidar atmospheric monitor

    International Nuclear Information System (INIS)

    Taylor, L.H.; Suhre, D.R.; Mani, S.S.

    1996-01-01

    The atmospheric monitor conceptual design is based on a pulsed CO 2 laser. The narrow laser lines provide high spectral selectivity in the 9-11 μm region, within the 8-14 μm ''fingerprint'' region where most large molecules have unique spectral absorption signatures. Laser power has been chosen so that topological objects, e.g., trees or buildings, as far as 4 km can be used as backreflectors, but the laser intensity is sufficiently low that the laser beam is eye-safe. Time-of-flight measurements give the distance to the topological reflector. The lidar system is augmented with an acousto-optic tunable filter (AOTF) which measures the thermal emission spectra from 3 to 14 μm with a 3 cm -1 passband. Sensitivity to narrow emission lines is enhanced by derivative spectroscopy in which the passband of the AOTF is dithered via the rf drive. Path-averaged concentrations are determined from the emission intensity and laser- determined range

  20. Tunable Polymer Fiber Bragg Grating (FBG) Inscription: Fabrication of Dual-FBG Temperature Compensated Polymer Optical Fiber Strain Sensors

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole

    2012-01-01

    We demonstrate stable wavelength tunable inscription of polymer optical fiber Bragg gratings (FBGs). By straining the fiber during FBG inscription, we linearly tune the center wavelength over 7 nm with less than 1% strain. Above 1% strain, the tuning curve saturates and we show a maximum tuning...... of 12 nm with 2.25% strain. We use this inscription method to fabricate a dual-FBG strain sensor in a poly (methyl methacrylate) single-mode microstructured polymer optical fiber and demonstrate temperature compensated strain sensing around 850 nm....

  1. Frequency-addressed tunable transmission in optically thin metallic nanohole arrays with dual-frequency liquid crystals

    International Nuclear Information System (INIS)

    Hao Qingzhen; Zhao Yanhui; Juluri, Bala Krishna; Kiraly, Brian; Huang, Tony Jun; Liou, Justin; Khoo, Iam Choon

    2011-01-01

    Frequency-addressed tunable transmission is demonstrated in optically thin metallic nanohole arrays embedded in dual-frequency liquid crystals (DFLCs). The optical properties of the composite system are characterized by the transmission spectra of the nanoholes, and a prominent transmission peak is shown to originate from the resonance of localized surface plasmons at the edges of the nanoholes. An ∼17 nm shift in the transmission peak is observed between the two alignment configurations of the liquid crystals. This DFLC-based active plasmonic system demonstrates excellent frequency-dependent switching behavior and could be useful in future nanophotonic applications.

  2. Dataset on electro-optically tunable smart-supercapacitors based on oxygen-excess nanograin tungsten oxide thin film

    Directory of Open Access Journals (Sweden)

    Akbar I. Inamdar

    2017-10-01

    Full Text Available The dataset presented here is related to the research article entitled “Highly Efficient Electro-optically Tunable Smart-supercapacitors Using an Oxygen-excess Nanograin Tungsten Oxide Thin Film” (Akbar et al., 2017 [9] where we have presented a nanograin WO3 film as a bifunctional electrode for smart supercapacitor devices. In this article we provide additional information concerning nanograin tungsten oxide thin films such as atomic force microscopy, Raman spectroscopy, and X-ray diffraction spectroscopy. Moreover, their electrochemical properties such as cyclic voltammetry, electrochemical supercapacitor properties, and electrochromic properties including coloration efficiency, optical modulation and electrochemical impedance spectroscopy are presented.

  3. Transition-edge sensor arrays for UV-optical-IR astrophysics

    International Nuclear Information System (INIS)

    Burney, J.; Bay, T.J.; Barral, J.; Brink, P.L.; Cabrera, B.; Castle, J.P.; Miller, A.J.; Nam, S.; Rosenberg, D.; Romani, R.W.; Tomada, A.

    2006-01-01

    Our research group has developed and characterized transition-edge sensor (TES) arrays for near IR-optical-near UV astrophysical observations. These detectors have a time-stamp accuracy of 0.3μs and an energy resolution of 0.16eV for 2.33eV photons at very high rates (30kHz). We have installed a 6x6 array of these TESs in an adiabatic demagnetization refrigerator equipped with windows for direct imaging. We discuss new instrumentation progress and current data in all aspects related to successful operation of this camera system, including: detector and array performance, position dependence and cross-talk, low-temperature and readout electronics, quantum and system efficiency, IR filtering, and focus and imaging

  4. Image transmission in mid-IR using a solid state laser pumped optical parametric oscillator

    Science.gov (United States)

    Prasad, Narasimha S.; Kratovil, Pat; Magee, James R.

    2002-04-01

    In this paper, image transmission using a mid-wave IR (MWIR) optical transceiver based free-space data link under low visibility conditions is presented. The all-solid-state MWIR transceiver primarily consisted of a passively Q-switched, short-pulsed Nd:YAG laser pumping a periodically poled lithium niobate (PPLN) based optical parametric oscillator and a Dember effect detector. The MILES transceiver generates pulse position waveforms. The optical data link consisting of transmitter drive electronics, pulse conditioning electronics and a computer generating pulses compatible with the 2400-baud rate RS232 receiver was utilized. Data formatting and RS232 transmission and reception were achieved using a computer. Data formatting transformed an arbitrary image file format compatible with the basic operation of pump laser. Images were transmitted at a date rate of 2400 kbits/sec with 16 bits/pixel. Test images consisting of 50X40 pixels and 100X80 pixels were transmitted through free-space filled with light fog up to 120 ft. Besides optical parametric oscillators, the proposed concept can be extended to optical parametric amplifiers, Raman lasers and other nonlinear optical devices to achieve multi-functionality.

  5. Optical design for a breadboard high-resolution spectrometer for SIRTF/IRS

    Science.gov (United States)

    Brown, Robert J.; Houck, James R.; van Cleve, Jeffrey E.

    1996-11-01

    The optical design of a breadboard high resolution infrared spectrometer for the IRS instrument on the SIRTF mission is discussed. The spectrometer uses a crossed echelle grating configuration to cover the spectral region from 10 to 20 micrometer with a resolving power of approximately equals 600. The all reflective spectrometer forms a nearly diffraction limited image of the two dimensional spectrum on a 128 multiplied by 128 arsenic doped silicon area array with 75 micrometer pixels. The design aspects discussed include, grating numerology, image quality, packaging and alignment philosophy.

  6. Optical and near-IR study of LMC HII region N11AB

    International Nuclear Information System (INIS)

    Lee, M.G.

    1990-01-01

    N11 (DEM 34), complex HII region located about 4 degrees from the center of the LMC bar, is a very interesting giant interstellar shell. It has a complicated structure and motion. It is located on the edge of an HI concentration. This is the progress report of the study of its two components, A and B at the optical and near-IR wavelengths to investigate stars, dust and ionized gas associated with them. N11A is a compact high-excitation blob and N11B is a bright HII region in this complex, which embeds OB association Lucke-Hodge 10

  7. Optical patterning and dynamics of torons and hopfions in a chiral nematic with photo-tunable equilibrium pitch

    Science.gov (United States)

    Sohn, Hayley; Ackerman, Paul; Smalyukh, Ivan

    Three-dimensional (3D) topological solitons arise in field theories ranging from particle physics to condensed matter and cosmology. They are the 3D counterparts of 2D skyrmions (often called ``baby skyrmions''), which attract a great deal of interest in studies of chiral ferromagnets and enable the emerging field of skyrmionics. In chiral nematic liquid crystals, the stability of such solitons is enhanced by the chiral medium's tendency to twist the director field describing the 3D spatial patterns of molecular alignment. However, their experimental realization, control and detailed studies remain limited. We combine experimental realization and numerical modeling of such light-responsive solitonic structures, including elementary torons and hopfions, in confined chiral nematic liquid crystals with photo-tunable cholesteric pitch. We show that the optical tunability of the pitch allows for using low-intensity light to control the soliton stability, dimensions, spatial patterning and dynamics.

  8. Extremely Lightweight Segmented Membrane Optical Shell Fabrication Technology for Future IR to Optical Telescope, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose that the Membrane Optical Shell Technology (MOST) substrate fabrication approach be extended with a specific focus on advanced off-axis very light weight,...

  9. High-energy kHz mid-IR tunable PPSLT-based OPO pumped at 1064 nm

    Energy Technology Data Exchange (ETDEWEB)

    Gaydardzhiev, A; Chuchumishev, D; Draganov, D; Buchvarov, I [Department of Physics, Sofia University, 5 James Bourchier Blvd., BG-1164, Sofia (Bulgaria)

    2012-06-30

    We report a single-frequency sub-nanosecond optical parametric oscillator (OPO) based on periodically poled stoichiometric lithium tantalate (PPSLT), pumped by a 1064-nm amplified microchip laser at a repetition rate of 0.5 kHz. Using a 11-mm-long PPSLT crystal polled with three different domain periods (30.2, 30.3, 30.4 {mu}m) and changing the temperature of the crystal from 20 Degree-Sign C to 265 Degree-Sign C, we have achieved wavelength tuning between 2990 nm and 3500 nm. The high nonlinearity of the used medium and the large aperture (2 mm) ensure the maximum idler output energy of {approx}0.5 mJ in the whole tuning range, corresponding to average {approx}10.5 % idler conversion efficiency and {approx}250 mW of average power. Sub-nanosecond pulse durations have been obtained for the idler at 0.88-ns pulse duration of the pump.

  10. Research on tunable multiwavelength fiber lasers with two-section birefringence fibers and a nonlinear optical loop

    Science.gov (United States)

    Chen, Jiao; Tong, Zhengrong; Zhang, Weihua; Xue, Lifang; Pan, Honggang

    2018-05-01

    Two types of tunable multiwavelength fiber lasers based on two-section polarization maintaining fibers (PMFs) cascaded/in parallel and nonlinear optical loop are proposed and experimentally demonstrated. Two-section cascaded PMFs and two polarization controllers (PCs) form the two-stage Lyot filter, which can generate comb spectrum to achieve multiwavelength output. When two sections of PMFs are in parallel, PCs in two paths are adjusted to change the beam’s polarization to suppress the light of one branch, and then the light of the other branch passes through the cavity. Additionally, a nonlinear optical loop acts as an intensity-dependent component, which can suppress the mode competition to maintain a stable output of multiwavelength lasing. The nonlinear optical loop is made by a 3 dB coupler, a PC3, and a 200 m high nonlinear fiber. Two types of tunable multiwavelength fiber lasers can achieve tuning of the channel space and the number of lasing wavelengths by adjusting PC1 and PC2. The channel space of the multiwavelengh laser can be tuned at nearly 0.4, 0.68, and 0.92 nm. Meanwhile, the spectral range of multiwavelength lasing can be controlled by PC3 in the nonlinear optical loop, and the tuning range of two multiwavelength lasers is about 2.28 and 1.45 nm, respectively.

  11. An organic dye-polymer (phenol red-poly (vinyl alcohol)) composite architecture towards tunable -optical and -saturable absorption characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Sreedhar, Sreeja, E-mail: sreejasreedhar83@gmail.com; Muneera, C. I., E-mail: drcimuneera@hotmail.com [Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram 695581, Kerala (India); Illyaskutty, Navas [Institute for Sensorics and Information Systems (ISIS), Karlsruhe University of Applied Sciences, Moltkestr. 30, D-76133 Karlsruhe (Germany); Sreedhanya, S. [School of Chemical Sciences, M. G. University, Kottayam, Kerala 686560 (India); Philip, Reji [Light and Matter Physics Group, Raman Research Institute, Bangalore 560080 (India)

    2016-05-21

    Herein, we demonstrate that blending an organic dye (guest/filler), with a vinyl polymer (host template), is an inexpensive and simple approach for the fabrication of multifunctional photonic materials which could display an enhancement in the desirable properties of the constituent materials and, at the same time provide novel synergistic properties for the guest-host system. A new guest-host nanocomposite system comprising Phenol Red dye and poly (vinyl alcohol) as guest and host template, respectively, which exhibits tunable optical characteristics and saturable absorption behavior, is introduced. The dependence of local electronic environment provided by the polymer template and the interactions of the polymer molecules with the encapsulated guest molecules on the observed optical/nonlinear absorption behavior is discussed. An understanding of the tunability of the optical/ photophysical processes, with respect to the filler content, as discussed herein could help in the design of improved optical materials for several photonic device applications like organic light emitting diodes and saturable absorbers.

  12. Tunable error-free optical frequency conversion of a 4ps optical short pulse over 25 nm by four-wave mixing in a polarisation-maintaining optical fibre

    Science.gov (United States)

    Morioka, T.; Kawanishi, S.; Saruwatari, M.

    1994-05-01

    Error-free, tunable optical frequency conversion of a transform-limited 4.0 ps optical pulse signalis demonstrated at 6.3 Gbit/s using four-wave mixing in a polarization-maintaining optical fibre. The process generates 4.0-4.6 ps pulses over a 25nm range with time-bandwidth products of 0.31-0.43 and conversion power penalties of less than 1.5 dB.

  13. Magneto-optical polarization rotation in a ladder-type atomic system for tunable offset locking

    Energy Technology Data Exchange (ETDEWEB)

    Parniak, Michał, E-mail: michal.parniak@fuw.edu.pl; Leszczyński, Adam; Wasilewski, Wojciech [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw (Poland)

    2016-04-18

    We demonstrate an easily tunable locking scheme for stabilizing frequency-sum of two lasers on a two-photon ladder transition based on polarization rotation in warm rubidium vapors induced by magnetic field and circularly polarized drive field. Unprecedented tunability of the two-photon offset frequency is due to strong splitting and shifting of magnetic states in external field. In our experimental setup, we achieve two-photon detuning of up to 700 MHz.

  14. Large-format platinum silicide microwave kinetic inductance detectors for optical to near-IR astronomy.

    Science.gov (United States)

    Szypryt, P; Meeker, S R; Coiffard, G; Fruitwala, N; Bumble, B; Ulbricht, G; Walter, A B; Daal, M; Bockstiegel, C; Collura, G; Zobrist, N; Lipartito, I; Mazin, B A

    2017-10-16

    We have fabricated and characterized 10,000 and 20,440 pixel Microwave Kinetic Inductance Detector (MKID) arrays for the Dark-speckle Near-IR Energy-resolved Superconducting Spectrophotometer (DARKNESS) and the MKID Exoplanet Camera (MEC). These instruments are designed to sit behind adaptive optics systems with the goal of directly imaging exoplanets in a 800-1400 nm band. Previous large optical and near-IR MKID arrays were fabricated using substoichiometric titanium nitride (TiN) on a silicon substrate. These arrays, however, suffered from severe non-uniformities in the TiN critical temperature, causing resonances to shift away from their designed values and lowering usable detector yield. We have begun fabricating DARKNESS and MEC arrays using platinum silicide (PtSi) on sapphire instead of TiN. Not only do these arrays have much higher uniformity than the TiN arrays, resulting in higher pixel yields, they have demonstrated better spectral resolution than TiN MKIDs of similar design. PtSi MKIDs also do not display the hot pixel effects seen when illuminating TiN on silicon MKIDs with photons with wavelengths shorter than 1 µm.

  15. Enhancement of Optical Adaptive Sensing by Using a Dual-Stage Seesaw-Swivel Actuator with a Tunable Vibration Absorber

    Directory of Open Access Journals (Sweden)

    Po-Chien Chou

    2011-05-01

    Full Text Available Technological obstacles to the use of rotary-type swing arm actuators to actuate optical pickup modules in small-form-factor (SFF disk drives stem from a hinge’s skewed actuation, subsequently inducing off-axis aberrations and deteriorating optical quality. This work describes a dual-stage seesaw-swivel actuator for optical pickup actuation. A triple-layered bimorph bender made of piezoelectric materials (PZTs is connected to the suspension of the pickup head, while the tunable vibration absorber (TVA unit is mounted on the seesaw swing arm to offer a balanced force to reduce vibrations in a focusing direction. Both PZT and TVA are designed to satisfy stable focusing operation operational requirements and compensate for the tilt angle or deformation of a disc. Finally, simulation results verify the performance of the dual-stage seesaw-swivel actuator, along with experimental procedures and parametric design optimization confirming the effectiveness of the proposed system.

  16. Widely tunable asymmetric long-period fiber grating with high sensitivity using optical polymer on laser-ablated cladding.

    Science.gov (United States)

    Chen, Nan-Kuang; Hsu, Der-Yi; Chi, Sien

    2007-08-01

    We demonstrate high-efficiency, wideband-tunable, laser-ablated long-period fiber gratings that use an optical polymer overlay. Portions of the fiber cladding are periodically removed by CO(2) laser pulses to induce periodic index changes for coupling the core mode into cladding modes. An optical polymer with a high thermo-optic coefficient with a dispersion distinct from that of silica is used on a deep-ablated cladding structure so that the effective indices of cladding modes become dispersive and the resonant wavelengths can be efficiently tuned. The tuning efficiency can be as high as 15.8 nm/ degrees C, and the tuning range can be wider than 105 nm (1545-1650 nm).

  17. All-optical switching based on a tunable Fano-like resonance in nonlinear ferroelectric photonic crystals

    International Nuclear Information System (INIS)

    Chai, Zhen; Hu, Xiaoyong; Gong, Qihuang

    2013-01-01

    A low-power all-optical switching is presented based on the all-optical tunable Fano-like resonance in a two-dimensional nonlinear ferroelectric photonic crystal made of polycrystalline lithium niobate. An asymmetric Fano-like line shape is achieved in the transmission spectrum by using two cascaded and uncoupled photonic crystal microcavities. The physical mechanism underlying the all-optical switching is attributed to the dynamic shift of the Fano-like resonance peak caused by variations in the dispersion relations of the photonic crystal structure induced by pump light. A large switching efficiency of 61% is reached under excitation of a weak pump light with an intensity as low as 1 MW cm −2 . (paper)

  18. Optical Response of Cu1-xZnxIr2S4 Due to Metal--Insulator Transition

    International Nuclear Information System (INIS)

    Chen, L.; Matsunami, M.; Nanba, T.; Cao, G.; Suzuki, H.; Isobe, M.; Matsumoto, T.

    2003-01-01

    The mother material CuIr 2 S 4 of the thiospinel system Cu 1-x Zn x Ir 2 S 4 undergoes a temperature-induced metal--insulator (Mi) transition. We report the temperature dependence of the optical reflection spectra of Cu 1-x Zn x Ir 2 S 4 (x ≤ 0.5) at the temperatures of 8-300 K in the energy regions of 0.005--30 eV in order to study the change in the electronic structure due to the Zn substitution for Cu. Zn substitution induced mainly the splitting of the hybridization band between the Ir-5d(t 2g ) and S-3 p states crossing the E F . Obtained optical conductivity (σ ) spectrum is discussed in relation to the change in the electronic structure close to the E F . (author)

  19. Performance studies of an IR fiber optic sensor for chlorinated hydrocarbons in water

    International Nuclear Information System (INIS)

    Goebel, R.; Krska, R.; Neal, S.; Kellner, R.

    1994-01-01

    Chlorinated hydrocarbons (CHCs) were monitored using a recently presented infrared fiber-optic physico-chemical sensor consisting of an MIR transparent, polymer coated, silver halide fiber coupled to a commercial FTIR spectrometer. The aim of this study was to test the performance of this new fiber optic sensing device with respect to temperature dependence, simultaneous detection of several CHCs, sensitivity and dynamic response behavior. In addition the diffusion process of the CHCs into the polymer was analyzed in order to better understand and evaluate the obtained results. During the investigation of the temperature dependence of the sensor response to real trend could be observed in the temperature range of 0 to 22 C. The dynamic response of the sensor is in the minute range when experiencing an increase in concentration of the analyte while with a decrease in concentration, the response is relatively slow. The sensor enabled the detection of 10 environmentally relevant CHCs at concentrations of 1 to 50 ppm. The simulation of the experimental diffusion data revealed Fick's 1st law diffusion for CHCs into the polymer layers. Finally the sensing device was validated with head spacegas chromatography (HSGC) analyses and showed good agreement with these already established methods. This work shows the great potential of IR fiber optic sensors as early warning systems for a variety of CHCs in water (''threshold alarm sensor'') (orig.)

  20. Ultraviolet SO lasers optically pumped by a tunable, line-narrowed KrF laser

    International Nuclear Information System (INIS)

    Stuart, B.C.D.

    1992-06-01

    The feasibility of an ultraviolet energy storage laser based on the long-lived sulfur monoxide A 3 π-χ 3 Σ - electronic transition was investigated, and an ultraviolet laser based on the short-lived SO(B 3 Σ - -χ 3 Σ - ) transition was demonstrated and modeled. Both were optically pumped by a continuously tunable, line-narrowed KrF laser developed for efficient rotationally resolved excitation of SO. SO was produced by both microwave discharge and excimer laser photolysis of the precursor molecules SO 2 and SOCl 2 , with a maximum SO concentration (10 16 cm -3 ) generated by ArF (193 nm) photodissociation of SO 2 . Laser induced fluorescence of SO was used to study the excitation spectroscopy, vibrational branching ratios, lifetimes and deactivation rates. The radiative lifetime of SO(A 3 π 2 ,v' = 5) was measured to be 6.9 μs and that of SO(B,v' = 1) to be 33 ns. Lifetimes in the highly perturbed SO(B,v' = 2) level ranged from 28--90 ns. Measurements and modeling of the excitation saturation fluence as a function of buffer gas pressure determined what fraction of the ground state SO(X) molecules could be excited to SO(A) or SO(B). No evidence of excited state absorption was seen. Lasing on six new ultraviolet SO(B-X) vibrational bands in the range 262--315 nm was demonstrated. SO(B-X) pulse energies of up to 11 μJ were obtained and the gain coefficient was estimated to be 0.1 cm -1 . A multi-level rate equation model of the SO(B-X) excitation and lasing transitions, including collisional rotational mixing, described the dynamics of the lasing and measured output very well. Modeling showed and experiments confirmed that the maximum possible SO laser gain simply corresponded to saturating the excitation of a single rotational level. Collisional coupling of the rotational levels increased the laser output energy

  1. Mirrors for High Resolution X-Ray Optics---Figure Preserving IR/PT Coating

    Science.gov (United States)

    Chan, Kai-Wing; Olsen, Lawrence; Sharpe, Marton; Numata, Ai; McClelland, Ryan; Saha, Timo; Zhang, Will

    2016-01-01

    Coating stress of 10 - 20 nm of Ir is sufficiently high to distort the figure of arc-second thin lightweight mirrors. For iridium: --Stress sigma 4 GPa for 15 nm film implies 60 Nm integrated stress-- Need less than 3 N/m (or stress less than 200 MPa) for sub-arcsecond optics. Basic Approaches for Mitigation. A. Annealing the film-- Glass can be heat up to 400 C without distortion. Silicon is even more resistant.-- It was found that recovery is limited by residual thermal stress from taking the mirror down from high T. B. Coating bi-layer films with compressive stress with tensile stress. C. Front-and-back coating with magnetron sputtering or atomic layer deposition-- Sputtering involve spanning of substrates. Geometric difference in setup (convexness/concaveness of curved mirrors) does not permit precise front-and-back matching-- Atomic layer deposition can provide a uniform deposition front and back simultaneously.

  2. Development of alkali halide-optics for high power-IR laser

    International Nuclear Information System (INIS)

    Pohl, L.

    1989-01-01

    In this work 'Development of Alkali Halide-Optics for High Power-IR Laser' we investigated the purification of sodiumchloride-, potassiumchloride- and potassiumbromide-raw materials. We succeeded to reduce the content of impurities like Cu, Pb, V, Cr, Mn, Fe, Co and Ni in these raw materials to the lower of ppb's by a Complex-Adsorption-Method (CAM). Crystals were grown from purified substances by 'Kyropoulos' method'. Windows were cur thereof, polished and measured by FTIR-spectroscopy. Analytical data showed, that the resulting crystals were of lower quality than the raw materials. Because of this fact crystal-growing-conditions have to undergo a special improvement. Alkali halide windows from other sources on the market had been tested. (orig.) [de

  3. Fabrication of Large Area Fishnet Optical Metamaterial Structures Operational at Near-IR Wavelengths

    Directory of Open Access Journals (Sweden)

    Dennis W. Prather

    2010-12-01

    Full Text Available In this paper, we demonstrate a fabrication process for large area (2 mm × 2 mm fishnet metamaterial structures for near IR wavelengths. This process involves: (a defining a sacrificial Si template structure onto a quartz wafer using deep-UV lithography and a dry etching process (b deposition of a stack of Au-SiO2-Au layers and (c a ‘lift-off’ process which removes the sacrificial template structure to yield the fishnet structure. The fabrication steps in this process are compatible with today’s CMOS technology making it eminently well suited for batch fabrication. Also, depending on area of the exposure mask available for patterning the template structure, this fabrication process can potentially lead to optical metamaterials spanning across wafer-size areas.

  4. Optical design of a versatile FIRST high-resolution near-IR spectrograph

    Science.gov (United States)

    Zhao, Bo; Ge, Jian

    2012-09-01

    We report the update optical design of a versatile FIRST high resolution near IR spectrograph, which is called Florida IR Silicon immersion grating spectromeTer (FIRST). This spectrograph uses cross-dispersed echelle design with white pupils and also takes advantage of the image slicing to increase the spectra resolution, while maintaining the instrument throughput. It is an extremely high dispersion R1.4 (blazed angle of 54.74°) silicon immersion grating with a 49 mm diameter pupil is used as the main disperser at 1.4μm -1.8μm to produce R=72,000 while an R4 echelle with the same pupil diameter produces R=60,000 at 0.8μm -1.35μm. Two cryogenic Volume Phase Holographic (VPH) gratings are used as cross-dispersers to allow simultaneous wavelength coverage of 0.8μm -1.8μm. The butterfly mirrors and dichroic beamsplitters make a compact folding system to record these two wavelength bands with a 2kx2k H2RG array in a single exposure. By inserting a mirror before the grating disperser (the SIG and the echelle), this spectrograph becomes a very efficient integral field 3-D imaging spectrograph with R=2,000-4,000 at 0.8μm-1.8μm by coupling a 10x10 telescope fiber bundle with the spectrograph. Details about the optical design and performance are reported.

  5. Broadly tunable, beta-barium-borate-based, pulsed optical parametric oscillators and their potential applications in medicine

    Science.gov (United States)

    Sobey, Mark S.; Clark, Jim; Johnson, Bertram C.

    1995-05-01

    With the recent availability of Beta Barium Borate (BBO) crystals in useful sizes at acceptable market prices, the promise of Optical Parametric Oscillators (OPOs) becoming practical tunable systems is finally being realized. Wavelength coverage from such systems extends from 420 nm to over 2400 nm when pumped in the UV. For medical applications their usage will be limited in the near term to low repetition rates (suitable for selective absorption applications in medicine such as colored tattoo removal or treating vascular lesions. For such high energy devices peak powers necessitate the use of articulating arms for beam delivery. For high repetition rate systems, energy outputs will be in the range of 100 to 500 (mu) J at kHz frequencies (up to 1 W average power). Peak powers are low enough that fiber optic delivery is possible. These systems may find selective absorption applications in ophthalmology.

  6. Hyper-spectral modulation fluorescent imaging using double acousto-optical tunable filter based on TeO2-crystals

    International Nuclear Information System (INIS)

    Zaytsev, Kirill I; Perchik, Alexey V; Chernomyrdin, Nikita V; Yurchenko, Stanislav O; Kudrin, Konstantin G; Reshetov, Igor V

    2015-01-01

    We have proposed a method for hyper-spectral fluorescent imaging based on acousto-optical filtering. The object of interest was pumped using ultraviolet radiation of mercury lamp equipped with monochromatic excitation filter with the window of transparency centered at 365 nm. Double TeO 2 -based acousto-optical filter, tunable in range from 430 to 780 nm and having 2 nm bandwidth of spectral transparency, was used in order to detect quasimonochromatic images of object fluorescence. Modulating of ultraviolet pump intensity was used in order to reduce an impact of non-fluorescent background on the sample fluorescent imaging. The technique for signal-to-noise ratio improvement, based on fluorescence intensity estimation via digital processing of modulated video sequence of fluorescent object, was introduced. We have implemented the proposed technique for the test sample studying and we have discussed its possible applications

  7. Elimination of residual amplitude modulation in tunable diode laser wavelength modulation spectroscopy using an optical fiber delay line.

    Science.gov (United States)

    Chakraborty, Arup Lal; Ruxton, Keith; Johnstone, Walter; Lengden, Michael; Duffin, Kevin

    2009-06-08

    A new fiber-optic technique to eliminate residual amplitude modulation in tunable diode laser wavelength modulation spectroscopy is presented. The modulated laser output is split to pass in parallel through the gas measurement cell and an optical fiber delay line, with the modulation frequency / delay chosen to introduce a relative phase shift of pi between them. The two signals are balanced using a variable attenuator and recombined through a fiber coupler. In the absence of gas, the direct laser intensity modulation cancels, thereby eliminating the high background. The presence of gas induces a concentration-dependent imbalance at the coupler's output from which the absolute absorption profile is directly recovered with high accuracy using 1f detection.

  8. Tunable laser applications

    CERN Document Server

    Duarte, FJ

    2008-01-01

    Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

  9. Path to a UV/Optical/IR Flagship: Review of ATLAST and Its Predecessors

    Science.gov (United States)

    Thronson, Harley; Bolcar, Matthew R.; Clampin, Mark; Crooke, Julie; Feinberg, Lee; Oegerle, William; Rioux, Norman; Stahl, H. Philip; Stapelfeldt, Karl

    2016-01-01

    Our recently completed study for the Advanced Technology Large-Aperture Space Telescope (ATLAST) was the culmination of three years of initially internally funded work that built upon earlier engineering designs, science objectives, and technology priorities. Beginning in the mid-1980s, multiple teams of astronomers, technologists, and engineers developed concepts for a large-aperture UV/optical/IR space observatory intended to follow the Hubble Space Telescope (HST). Here, we summarize since the first significant conferences on major post-HST ultraviolet, optical, and infrared (UVOIR) observatories the history of designs, scientific goals, key technology recommendations, and community workshops. Although the sophistication of science goals and the engineering designs both advanced over the past three decades, we note the remarkable constancy of major characteristics of large post-HST UVOIR concepts. As it has been a priority goal for NASA and science communities for a half-century, and has driven much of the technology priorities for major space observatories, we include the long history of concepts for searching for Earth-like worlds. We conclude with a capsule summary of our ATLAST reference designs developed by four partnering institutions over the past three years, which was initiated in 2013 to prepare for the 2020 National Academies' Decadal Survey.

  10. Nonlinear optical response of chalcogenide glassy semiconductors in the IR and THz ranges studied with the femtosecond resolution in time

    DEFF Research Database (Denmark)

    Romanova, E.; Guizard, S.; Wang, Tianwu

    2017-01-01

    Two time-resolved experimental methods have been used for characterization of the non-linear optical response of chalcogenide glasses of the system As-S-Se-Te in IR and THz ranges upon excitation by femtosecond laser pulses at 800 nm wavelength. Photoinduced conductivity and refractivity were stu...

  11. Retrieval of Surface Lambert Albedos and Aerosols Optical Depths Using OMEGA Near-IR EPF Observations of Mars

    Science.gov (United States)

    Vincendon, M.; Langevin, Y.; Poulet, F.; Bibring, J.-P.; Gondet, B.

    2007-03-01

    We have analyzed five EPF sequences acquired by OMEGA/Mars Express in the near-IR over ice-free and ice-covered surfaces to retrieve simultaneously the Lambert albedo of the surface and the optical depth of aerosols.

  12. Tunable All-Optical Wavelength Conversion Based on Cascaded SHG/DFG in a Ti:PPLN Waveguide Using a Single CW Control Laser

    DEFF Research Database (Denmark)

    Hu, Hao; Nouroozi, Rahman; Wang, Wenrui

    2012-01-01

    Tunable all-optical wavelength conversion (AOWC) of a 40-Gb/s RZ-OOK data signal based on cascaded second-harmonic generation (SHG) and difference-frequency generation (DFG) in a Ti:PPLN waveguide is demonstrated. Error-free performances with negligible power penalty are achieved for the wavelength...

  13. An efficient method for the creation of tunable optical line traps via control of gradient and scattering forces.

    Science.gov (United States)

    Tietjen, Gregory T; Kong, Yupeng; Parthasarathy, Raghuveer

    2008-07-07

    Interparticle interaction energies and other useful physical characteristics can be extracted from the statistical properties of the motion of particles confined by an optical line trap. In practice, however, the potential energy landscape, U(x), imposed by the line provides an extra, and in general unknown, influence on particle dynamics. We describe a new class of line traps in which both the optical gradient and scattering forces acting on a trapped particle are designed to be linear functions of the line coordinate and in which their magnitude can be counterbalanced to yield a flat U(x). These traps are formed using approximate solutions to general relations concerning non-conservative optical forces that have been the subject of recent investigations [Y. Roichman, B. Sun, Y. Roichman, J. Amato-Grill, and D. G. Grier, Phys. Rev. Lett. 100, 013602-4 (2008).]. We implement the lines using holographic optical trapping and measure the forces acting on silica microspheres, demonstrating the tunability of the confining potential energy landscape. Furthermore, we show that our approach efficiently directs available laser power to the trap, in contrast to other methods.

  14. Generation of tunable chain of three-dimensional optical bottle beams via focused multi-ring hollow Gaussian beam.

    Science.gov (United States)

    Philip, Geo M; Viswanathan, Nirmal K

    2010-11-01

    We report here the generation of a chain of three-dimensional (3-D) optical bottle beams by focusing a π-phase shifted multi-ring hollow Gaussian beam (HGB) using a lens with spherical aberration. The rings of the HGB of suitable radial (k(r)) and axial (k(z)) wave vectors are generated using a double-negative axicon chemically etched in the optical fiber tips. Moving the lens position with respect to the fiber tip results in variation of the semi-angle of the cones of wave vectors of the HGBs and their diameter, using which we demonstrate tunability in the size and the periodicity of the 3-D optical bottle beams over a wide range, from micrometers to millimeters. The propagation characteristics of the beams resulting from focusing of single- and multi-ring HGBs and resulting in a quasi-non-diffracting beam and a chain of 3-D optical bottle beams, respectively, are simulated using only the input beam parameters and are found to agree well with experimental results.

  15. High-energy, tunable, mid-infrared, picosecond optical parametric generation in CdSiP2

    Science.gov (United States)

    Chaitanya Kumar, S.; Jelínek, M.; Baudisch, M.; Zawilski, K. T.; Schunemann, P. G.; Kubecek, V.; Biegert, J.; Ebrahim-Zadeh, M.

    2012-06-01

    We report a tunable, high-energy, single-pass, optical parametric generator (OPG) based on the new nonlinear material, cadmium silicon phosphide, CdSiP2. The OPG is pumped by a laboratory designed cavity-dumped passively mode-locked, diode-pumped, Nd:YAG oscillator, providing 25 μJ pulses in 20 ps at 5 Hz. The pump energy is further boosted by a flashlamp-pumped Nd:YAG amplifier to 2.5 mJ. The OPG is temperature tunable over 1263-1286 nm (23 nm) in the signal and 6153-6731 nm (578 nm) in the idler, corresponding to a total tuning range of 601 nm. Using the single-pass OPG configuration, we have generated signal energy as high as 636 μJ at 1283 nm, together with an idler energy of 33 μJ at 6234 nm, for 2.1 mJ of input pump energy. The signal pulses generated from the OPG have a Gaussian pulse duration of 24 ps and an FWHM spectral bandwidth of 10.4 nm at central wavelength of 1276 nm. The corresponding idler spectrum has an FWHM bandwidth of 140 nm centered at 6404 nm.

  16. All-optical differential equation solver with constant-coefficient tunable based on a single microring resonator.

    Science.gov (United States)

    Yang, Ting; Dong, Jianji; Lu, Liangjun; Zhou, Linjie; Zheng, Aoling; Zhang, Xinliang; Chen, Jianping

    2014-07-04

    Photonic integrated circuits for photonic computing open up the possibility for the realization of ultrahigh-speed and ultra wide-band signal processing with compact size and low power consumption. Differential equations model and govern fundamental physical phenomena and engineering systems in virtually any field of science and engineering, such as temperature diffusion processes, physical problems of motion subject to acceleration inputs and frictional forces, and the response of different resistor-capacitor circuits, etc. In this study, we experimentally demonstrate a feasible integrated scheme to solve first-order linear ordinary differential equation with constant-coefficient tunable based on a single silicon microring resonator. Besides, we analyze the impact of the chirp and pulse-width of input signals on the computing deviation. This device can be compatible with the electronic technology (typically complementary metal-oxide semiconductor technology), which may motivate the development of integrated photonic circuits for optical computing.

  17. Broadband and tunable optical parametric generator for remote detection of gas molecules in the short and mid-infrared.

    Science.gov (United States)

    Lambert-Girard, Simon; Allard, Martin; Piché, Michel; Babin, François

    2015-04-01

    The development of a novel broadband and tunable optical parametric generator (OPG) is presented. The OPG properties are studied numerically and experimentally in order to optimize the generator's use in a broadband spectroscopic LIDAR operating in the short and mid-infrared. This paper discusses trade-offs to be made on the properties of the pump, crystal, and seeding signal in order to optimize the pulse spectral density and divergence while enabling energy scaling. A seed with a large spectral bandwidth is shown to enhance the pulse-to-pulse stability and optimize the pulse spectral density. A numerical model shows excellent agreement with output power measurements; the model predicts that a pump having a large number of longitudinal modes improves conversion efficiency and pulse stability.

  18. Electrically tunable whispering gallery mode microresonator based on a grapefruit-microstructured optical fiber infiltrated with nematic liquid crystals.

    Science.gov (United States)

    Yang, Chengkun; Zhang, Hao; Liu, Bo; Lin, Shiwei; Li, Yuetao; Liu, Haifeng

    2017-08-01

    An electrically tunable whispering gallery mode (WGM) microresonator based on an HF-etched microstructured optical fiber (MOF) infiltrated with nematic liquid crystals (NLCs) is proposed and experimentally demonstrated. Experimental results indicate that as the peak-to-peak voltage of the applied AC electric field increases from 160 to 220 V, WGM resonance peaks gradually move toward a shorter wavelength region by 0.527 nm with a wavelength sensitivity up to 0.01  nm/V for a TM1691 mode, and the Q-factor for each WGM resonance peak rapidly decreases with the increment of applied electric voltage. The proposed electrically controlled WGM tuning scheme shows a linear resonance wavelength shift with good spectral reversibility, which makes it a promising candidate to serve as an integrated functional photonic device in practical use and in related fundamental scientific studies.

  19. A new method of equalizing the optical power by a liquid crystal-based tunable encoder/decoder in SAC-OCDMA PON

    Science.gov (United States)

    Chen, He; Qiao, Yang; Zhao, Yanbin; Liu, Yang; Liu, Meilin; Liu, Lijun; Zhou, Bilei

    2015-11-01

    A new method of equalizing the optical power is proposed to enhance the performance in the SAC OCDMA PON. The method is to use a tunable liquid crystal-based tunable encoder for further development by voltage controlling individually, so it is achieved in one device for encoding and power equalization, the experimental results show that the system BER and eye diagram are greatly improved. Since the method does not use additional devices in the condition, the system are lower complexity and cost-effective.

  20. Fiber Bragg grating interrogation using wavelength modulated tunable distributed feedback lasers and a fiber-optic Mach-Zehnder interferometer.

    Science.gov (United States)

    Roy, Anirban; Chakraborty, Arup Lal; Jha, Chandan Kumar

    2017-04-20

    This paper demonstrates a technique of high-resolution interrogation of two fiber Bragg gratings (FBGs) with flat-topped reflection spectra centered on 1649.55 nm and 1530.182 nm with narrow line width tunable semiconductor lasers emitting at 1651.93 nm and 1531.52 nm, respectively. The spectral shift of the reflection spectrum in response to temperature and strain is accurately measured with a fiber-optic Mach-Zehnder interferometer that has a free spectral range of 0.0523 GHz and a broadband photodetector. Laser wavelength modulation and harmonic detection techniques are used to transform the gentle edges of the flat-topped FBG into prominent leading and trailing peaks that are up to five times narrower than the FBG spectrum. Either of these peaks can be used to accurately measure spectral shifts of the FBG reflection spectrum with a resolution down to a value of 0.47 pm. A digital signal processing board is used to measure the temperature-induced spectral shifts over the range of 30°C-80°C and strain-induced spectral shifts from 0  μϵ to 12,000  μϵ. The shift is linear in both cases with a temperature sensitivity of 12.8 pm/°C and strain sensitivity of 0.12  pm/μϵ. The distinctive feature of this technique is that it does not use an optical spectrum analyzer at any stage of its design or operation. It can be readily extended to all types of tunable diode lasers and is ideally suited for compact field instruments and for biomedical applications in stroke rehabilitation monitoring.

  1. Demonstration of a tunable two-frequency projected fringe pattern with acousto-optic deflectors

    International Nuclear Information System (INIS)

    Dupont, S.; Kastelik, J. C.

    2008-01-01

    We report on a fringe projector for three-dimensional shape measurement. The developed instrument is able to project a two-frequency fringe pattern, each frequency is independently controlled by electronics. Moreover, each phase of the two fringe patterns is also independently adjusted. The projection system is based on the use of a pair of custom large bandwidth (40 MHz) and high efficiency (60%) TeO 2 deflectors. The developed instrument offers the combined advantages of a static two-frequency fringe projector and of a tunable single frequency fringe projector

  2. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenbo [Imaging Unit, Integrative Oncology Department, BC Cancer Agency Research Center, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3 (Canada); Department of Dermatology and Skin Science, University of British Columbia, 835 West 10th Avenue, Vancouver, British Columbia V5Z 4E8 (Canada); Department of Biomedical Engineering, University of British Columbia, KAIS 5500, 2332 Main Mall, Vancouver, British Columbia V6T 1Z4 (Canada); Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan, E-mail: hzeng@bccrc.ca [Imaging Unit, Integrative Oncology Department, BC Cancer Agency Research Center, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3 (Canada); Department of Dermatology and Skin Science, University of British Columbia, 835 West 10th Avenue, Vancouver, British Columbia V5Z 4E8 (Canada)

    2016-06-15

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

  3. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

    International Nuclear Information System (INIS)

    Wang, Wenbo; Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

    2016-01-01

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

  4. Exploration of Mars in SPICAM-IR experiment onboard the Mars-Express spacecraft: 1. Acousto-optic spectrometer SPICAM-IR

    Science.gov (United States)

    Korablev, O. I.; Bertaux, J. L.; Kalinnikov, Yu. K.; Fedorova, A. A.; Moroz, V. I.; Kiselev, A. V.; Stepanov, A. V.; Grigoriev, A. V.; Zhegulev, V. S.; Rodin, A. V.; Dimarellis, E.; Dubois, J. P.; Reberac, A.; van Ransbeeck, E.; Gondet, B.

    2006-07-01

    The acousto-optic spectrometer of the near infrared range, which is a part of the spectrometer SPICAM onboard the Mars-Express spacecraft, began to operate in the orbit of Mars in January 2004. In the SPICAM experiment, a spectrometer on the basis of an acousto-optic filter was used for the first time to investigate other planets. During one and a half years of operation, the IR channel of SPICAM obtained more than half a million spectra in the 1-1.7 μm range with a resolving power of more than 1500 in different modes of observation: limb, nadir, and solar eclipses. The main goal of the experiment is to study the content of water vapor in the Martian atmosphere by measuring the absorption spectrum in the 1.38 μm band. Characteristics of the instrument (high spectral resolution and signal-to-noise ratio) allow one to solve a number of additional scientific problems including the study of ozone distribution by emission of singlet oxygen (O2 1Δg), detection of the water and carbonic dioxide ices, and also the study of the vertical distribution and optical characteristics of aerosol in the Martian atmosphere. We present a description of the instrument, the results of its ground and in-flight calibrations, and a brief survey of the basic scientific results obtained by the SPICAM spectrometer during a year-and-half of operation.

  5. FT-IR microscopical analysis with synchrotron radiation: The microscope optics and system performance

    International Nuclear Information System (INIS)

    Reffner, J.A.; Martoglio, P.A.; Williams, G.P.

    1995-01-01

    When a Fourier transform infrared (FT-IR) microspectrometer was first interfaced with the National Synchrotron Light Source (NSLS) in September 1993, there was an instant realization that the performance at the diffraction limit had increased 40-100 times. The synchrotron source transformed the IR microspectrometer into a true IR microprobe, providing high-quality IR spectra for probe diameters at the diffraction limit. The combination of IR microspectroscopy and synchrotron radiation provides a powerful new tool for molecular spectroscopy. The ability to perform IR microspectroscopy with synchrotron radiation is still under development at Brookhaven National Laboratory, but several initial studies have been completed that demonstrate the broad-ranging applications of this technology and its potential for materials characterization

  6. FT-IR microscopical analysis with synchrotron radiation: The microscope optics and system performance

    Energy Technology Data Exchange (ETDEWEB)

    Reffner, J.A.; Martoglio, P.A. [Spectra-Tech, Inc., Shelton, CT (United States); Williams, G.P. [Brookhaven National Lab., Upton, NY (United States)

    1995-01-01

    When a Fourier transform infrared (FT-IR) microspectrometer was first interfaced with the National Synchrotron Light Source (NSLS) in September 1993, there was an instant realization that the performance at the diffraction limit had increased 40-100 times. The synchrotron source transformed the IR microspectrometer into a true IR microprobe, providing high-quality IR spectra for probe diameters at the diffraction limit. The combination of IR microspectroscopy and synchrotron radiation provides a powerful new tool for molecular spectroscopy. The ability to perform IR microspectroscopy with synchrotron radiation is still under development at Brookhaven National Laboratory, but several initial studies have been completed that demonstrate the broad-ranging applications of this technology and its potential for materials characterization.

  7. All-optically tunable waveform synthesis by a silicon nanowaveguide ring resonator coupled with a photonic-crystal fiber frequency shifter

    KAUST Repository

    Savvin, Aleksandr D.

    2011-03-01

    A silicon nanowaveguide ring resonator is combined with a photonic-crystal fiber (PCF) frequency shifter to demonstrate an all-optically tunable synthesis of ultrashort pulse trains, modulated by ultrafast photoinduced free-carrier generation in the silicon resonator. Pump-probe measurements performed with a 50-fs, 625-nm second-harmonic output of a Cr:forsterite laser, used as a carrier-injecting pump, and a 1.50-1.56-μm frequency-tunable 100-fs soliton output of a photonic-crystal fiber, serving as a probe, resolve tunable ultrafast oscillatory features in the silicon nanowaveguide resonator response. © 2010 Elsevier B.V. All rights reserved.

  8. All-optically tunable waveform synthesis by a silicon nanowaveguide ring resonator coupled with a photonic-crystal fiber frequency shifter

    KAUST Repository

    Savvin, Aleksandr D.; Melnikov, Vasily; Fedotov, Il'ya V.; Fedotov, Andrei B.; Perova, Tatiana S.; Zheltikov, Aleksei M.

    2011-01-01

    A silicon nanowaveguide ring resonator is combined with a photonic-crystal fiber (PCF) frequency shifter to demonstrate an all-optically tunable synthesis of ultrashort pulse trains, modulated by ultrafast photoinduced free-carrier generation in the silicon resonator. Pump-probe measurements performed with a 50-fs, 625-nm second-harmonic output of a Cr:forsterite laser, used as a carrier-injecting pump, and a 1.50-1.56-μm frequency-tunable 100-fs soliton output of a photonic-crystal fiber, serving as a probe, resolve tunable ultrafast oscillatory features in the silicon nanowaveguide resonator response. © 2010 Elsevier B.V. All rights reserved.

  9. Anharmonic effects in IR, Raman, and Raman optical activity spectra of alanine and proline zwitterions.

    Science.gov (United States)

    Danecek, Petr; Kapitán, Josef; Baumruk, Vladimír; Bednárová, Lucie; Kopecký, Vladimír; Bour, Petr

    2007-06-14

    The difference spectroscopy of the Raman optical activity (ROA) provides extended information about molecular structure. However, interpretation of the spectra is based on complex and often inaccurate simulations. Previously, the authors attempted to make the calculations more robust by including the solvent and exploring the role of molecular flexibility for alanine and proline zwitterions. In the current study, they analyze the IR, Raman, and ROA spectra of these molecules with the emphasis on the force field modeling. Vibrational harmonic frequencies obtained with 25 ab initio methods are compared to experimental band positions. The role of anharmonic terms in the potential and intensity tensors is also systematically explored using the vibrational self-consistent field, vibrational configuration interaction (VCI), and degeneracy-corrected perturbation calculations. The harmonic approach appeared satisfactory for most of the lower-wavelength (200-1800 cm(-1)) vibrations. Modern generalized gradient approximation and hybrid density functionals, such as the common B3LYP method, provided a very good statistical agreement with the experiment. Although the inclusion of the anharmonic corrections still did not lead to complete agreement between the simulations and the experiment, occasional enhancements were achieved across the entire region of wave numbers. Not only the transitional frequencies of the C-H stretching modes were significantly improved but also Raman and ROA spectral profiles including N-H and C-H lower-frequency bending modes were more realistic after application of the VCI correction. A limited Boltzmann averaging for the lowest-frequency modes that could not be included directly in the anharmonic calculus provided a realistic inhomogeneous band broadening. The anharmonic parts of the intensity tensors (second dipole and polarizability derivatives) were found less important for the entire spectral profiles than the force field anharmonicities (third

  10. Tunable long-distance light transportation along Au nanoparticle chains: promising for optical interconnect

    Science.gov (United States)

    Lin, Z.; Li, X. D.; Chen, T. P.

    2014-10-01

    Tunable light resonance transportation along a single long Au hemisphere nanoparticles (NPs) chain was studied. The realistic experimentally determined gold dielectric function was used for the simulation of Au localized surface plasmon polariton (LSPPs) effect. The resonance light energy with minimized attenuation and its bandwidth were quantitatively analyzed by inducing the effective mass which was observed to increase only with the length of Au NPs between the source and the test point. The geometric ratio g/ r of NP size and gap were investigated at 5 µm far of NPs with different gaps from 0 to 70 nm. Strongest resonance can be achieved with g/ r = 1.2 by the factor of 1.5 than the connected NPs. This resonance mode falls in the wavelength λ = 555 nm (green light), which is exactly the maximum sensitivity of a light-adapted eye of human beings.

  11. In-plane deeply-etched optical MEMS notch filter with high-speed tunability

    International Nuclear Information System (INIS)

    Sabry, Yasser M; Eltagoury, Yomna M; Shebl, Ahmed; Khalil, Diaa; Soliman, Mostafa; Sadek, Mohamed

    2015-01-01

    Notch filters are used in spectroscopy, multi-photon microscopy, fluorescence instrumentation, optical sensors and other life science applications. One type of notch filter is based on a fiber-coupled Fabry–Pérot cavity, which is formed by a reflector (external mirror) facing a dielectric-coated end of an optical fiber. Tailoring this kind of optical filter for different applications is possible because the external mirror has fewer mechanical and optical constraints. In this paper we present optical modeling and implementation of a fiber-coupled Fabry–Pérot filter based on dielectric-coated optical fiber inserted into a micromachined fiber groove facing a metallized micromirror, which is driven by a high-speed MEMS actuator. The optical MEMS chip is fabricated using deep reactive ion etching (DRIE) technology on a silicon on insulator wafer, where the optical axis is parallel to the substrate (in-plane) and the optical/mechanical components are self-aligned by the photolithographic process. The DRIE etching depth is 150 μm, chosen to increase the micromirror optical throughput and improving the out-of-plane stiffness of the MEMS actuator. The MEMS actuator type is closing-gap, while its quality factor is almost doubled by slotting the fixed plate. A low-finesse Fabry–Pérot interferometer is formed by the metallized surface of the micromirror and a cleaved end of a standard single-mode fiber, for characterization of the MEMS actuator stroke and resonance frequency. The actuator achieves a travel distance of 800 nm at a resonance frequency of 89.9 kHz. The notch filter characteristics were measured using an optical spectrum analyzer, and the filter exhibits a free spectral range up to 100 nm and a notch rejection ratio up to 20 dB around a wavelength of 1300 nm. The presented device provides batch processing and low-cost production of the filter. (paper)

  12. Final Report on LDRD project 130784 : functional brain imaging by tunable multi-spectral Event-Related Optical Signal (EROS).

    Energy Technology Data Exchange (ETDEWEB)

    Speed, Ann Elizabeth; Spahn, Olga Blum; Hsu, Alan Yuan-Chun

    2009-09-01

    Functional brain imaging is of great interest for understanding correlations between specific cognitive processes and underlying neural activity. This understanding can provide the foundation for developing enhanced human-machine interfaces, decision aides, and enhanced cognition at the physiological level. The functional near infrared spectroscopy (fNIRS) based event-related optical signal (EROS) technique can provide direct, high-fidelity measures of temporal and spatial characteristics of neural networks underlying cognitive behavior. However, current EROS systems are hampered by poor signal-to-noise-ratio (SNR) and depth of measure, limiting areas of the brain and associated cognitive processes that can be investigated. We propose to investigate a flexible, tunable, multi-spectral fNIRS EROS system which will provide up to 10x greater SNR as well as improved spatial and temporal resolution through significant improvements in electronics, optoelectronics and optics, as well as contribute to the physiological foundation of higher-order cognitive processes and provide the technical foundation for miniaturized portable neuroimaging systems.

  13. Design of doubly focusing, tunable (5 to 30 keV), wide-bandpass optics made from layered synthetic microstructures

    International Nuclear Information System (INIS)

    Bilderback, D.H.; Lairson, B.M.; Barbee, T.W. Jr.; Ice, G.E.; Sparks, C.J. Jr.

    1982-01-01

    Layered Synthetic Microstructures (LSMs) show great promise as focusing, high-throughput, hard x-ray monochromators. Experimental reflectivity vs. energy curves have been obtained on carbon-tungsten and carbon-molybdenum LSMs of up to 260 layers in thickness. Reflectivities for three flat LSMs with different bandpasses were 70% with δE/E = 5.4%, 66% with δE/E = 1.4%, and 19% with δE/E = 0.6%. A new generation of variable bandwidth optics using two successive LSMs is proposed. The first element will be an LSM deposited on a substrate that can be water cooled as it intercepts direct radiation from a storage ring. It can be bent for vertical focusing. The bandpass can be adjusted by choosing interchangeable first elements from an assortment of LSM's with different bandpasses (for example, δE/E = 0.005, 0.01, 0.02, 0.05, 0.1). The second LSM will consist of a multilayered structure with a 10% bandpass built onto a flexible substrate that can be bent for sagittal focusing. The result will be double focusing optics with an adjustable energy bandpass that are tunable from 5 to 30 keV

  14. Optical Properties of Sol-Gel Nb2O5 Films with Tunable Porosity for Sensing Applications

    Directory of Open Access Journals (Sweden)

    Rosen Georgiev

    2015-01-01

    Full Text Available Thin Nb2O5 films with tunable porosity are deposited by the sol-gel and evaporation induced self-assembly methods using organic template Pluronic PE6100 with different molar fractions with respect to NbCl5 used as a precursor for synthesis of Nb sol. Surface morphology and structure of the films are studied by Transmission Electron Microscopy and Selected Area Electron Diffraction. The optical characterization of the films is carried out through reflectance spectra measurements of the films deposited on silicon substrates and theoretical modeling in order to obtain refractive index, extinction coefficient, and thickness of the films. The overall porosity of the films and the amount of adsorbed acetone vapors in the pores are quantified by means of Bruggeman effective medium approximation using already determined optical constants. The sensing properties of the samples are studied by measuring both the reflectance spectra and room-temperature photoluminescence spectra prior to and after exposure to acetone vapors and liquid, respectively. The potential of using the studied mesoporous Nb2O5 films for chemooptical sensing is demonstrated and discussed.

  15. Novel tunable optical filter employing a fiber loop mirror for synthesis applications in WDM

    OpenAIRE

    Vázquez García, María Carmen; Vargas Palma, Salvador Elías; Sánchez-Pena, José Manuel

    2001-01-01

    A novel optical filter employing a fiber loop mirror within an amplified ring resonator is presented. The fiber loop mirror allows tuning by changing the coupling factor of a coupler. The device can be used as a building block to synthesize optical filters, as previously reported, saving components. Publicado

  16. Rugged Low Temperature Actuators for Tunable Fabry Perot Optical Filters, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Why are rugged, low temperature actuator materials important? By themselves, they are useless; however, when fabricated into thin films and integrated into optical...

  17. Development of optics and microwave multiplexers for far-IR and millimeter detector arrays

    Data.gov (United States)

    National Aeronautics and Space Administration — The future of experimental cosmology and astrophysics is intimately tied to the progress of remote sensing technology of millimeter and far-IR instruments. I will...

  18. All-optical universal logic gates on nonlinear multimode interference coupler using tunable input intensity

    Science.gov (United States)

    Tajaldini, Mehdi; Jafri, Mohd Zubir Mat

    2015-04-01

    The theory of Nonlinear Modal Propagation Analysis Method (NMPA) have shown significant features of nonlinear multimode interference (MMI) coupler with compact dimension and when launched near the threshold of nonlinearity. Moreover, NMPA have the potential to allow studying the nonlinear MMI based the modal interference to explorer the phenomenon that what happen due to the natural of multimode region. Proposal of all-optical switch based NMPA has approved its capability to achieving the all-optical gates. All-optical gates have attracted increasing attention due to their practical utility in all-optical signal processing networks and systems. Nonlinear multimode interference devices could apply as universal all-optical gates due to significant features that NMPA introduce them. In this Paper, we present a novel Ultra-compact MMI coupler based on NMPA method in low intensity compared to last reports either as a novel design method and potential application for optical NAND, NOR as universal gates on single structure for Boolean logic signal processing devices and optimize their application via studding the contrast ratio between ON and OFF as a function of output width. We have applied NMPA for several applications so that the miniaturization in low nonlinear intensities is their main purpose.

  19. Integrated Wavelength-Tunable Light Source for Optical Gas Sensing Systems

    Directory of Open Access Journals (Sweden)

    Bin Li

    2015-01-01

    Full Text Available A compact instrument consisting of a distributed feedback laser (DFB at 1.65 μm was developed as a light source for gas sensing systems using tunable diode laser absorption spectroscopy (TDLAS technique. The wavelength of laser is tuned by adjusting the laser working temperature and injection current, which are performed by self-developed temperature controller and current modulator respectively. Stability test shows the fluctuation of the laser temperature is within the range of ±0.02°C. For gas detection experiments, the wavelength is tuned around the gas absorption line by adjusting laser temperature and is then shifted periodically to scan across the absorption line by the laser current modulator, which generates a 10 Hz saw wave signal. In addition, the current modulator is able to generate sine wave signal for gas sensing systems using wavelength modulation spectroscopy (WMS technique involving extraction of harmonic signals. The spectrum test proves good stability that the spectrum was measured 6 times every 10 minutes at the constant temperature and current condition. This standalone instrument can be applied as a light source for detection systems of different gases by integrating lasers at corresponding wavelength.

  20. Detector Sampling of Optical/IR Spectra: How Many Pixels per FWHM?

    Science.gov (United States)

    Robertson, J. Gordon

    2017-08-01

    Most optical and IR spectra are now acquired using detectors with finite-width pixels in a square array. Each pixel records the received intensity integrated over its own area, and pixels are separated by the array pitch. This paper examines the effects of such pixellation, using computed simulations to illustrate the effects which most concern the astronomer end-user. It is shown that coarse sampling increases the random noise errors in wavelength by typically 10-20 % at 2 pixels per Full Width at Half Maximum, but with wide variation depending on the functional form of the instrumental Line Spread Function (i.e. the instrumental response to a monochromatic input) and on the pixel phase. If line widths are determined, they are even more strongly affected at low sampling frequencies. However, the noise in fitted peak amplitudes is minimally affected by pixellation, with increases less than about 5%. Pixellation has a substantial but complex effect on the ability to see a relative minimum between two closely spaced peaks (or relative maximum between two absorption lines). The consistent scale of resolving power presented by Robertson to overcome the inadequacy of the Full Width at Half Maximum as a resolution measure is here extended to cover pixellated spectra. The systematic bias errors in wavelength introduced by pixellation, independent of signal/noise ratio, are examined. While they may be negligible for smooth well-sampled symmetric Line Spread Functions, they are very sensitive to asymmetry and high spatial frequency sub-structure. The Modulation Transfer Function for sampled data is shown to give a useful indication of the extent of improperly sampled signal in an Line Spread Function. The common maxim that 2 pixels per Full Width at Half Maximum is the Nyquist limit is incorrect and most Line Spread Functions will exhibit some aliasing at this sample frequency. While 2 pixels per Full Width at Half Maximum is nevertheless often an acceptable minimum for

  1. All-optically tunable EIT-like dielectric metasurfaces hybridized with thin phase change material layers

    Science.gov (United States)

    Petronijevic, Emilija; Sibilia, Concita

    2017-05-01

    Electromagnetically induced transparency (EIT), a pump-induced narrow transparency window within the absorption region of a probe, had offered new perspectives in slow-light control in atomic physics. For applications in nanophotonics, the implementation on chip-scaled devices has later been obtained by mimicking this effect by metallic metamaterials. High losses in visible and near infrared range of metal-based metamaterialls have recently opened a new field of all-dielectric metamaterials; a proper configuration of high refractive index dielectric nanoresonators can mimick this effect without losses to get high Q, slow-light response. The next step would be the ability to tune their optical response, and in this work we investigate thin layers of phase change materials (PCM) for all-optical control of EIT-like all-dielectric metamaterials. PCM can be nonvolatively and reversibly switched between two stable phases that differ in optical properties by applying a visible laser pulse. The device is based on Si nanoresonators covered by a thin layer of PCM GeTe; optical and transient thermal simulations have been done to find and optimize the fabrication parameters and switching parameters such as the intensity and duration of the pulse. We have found that the EIT-like response can be switched on and off by applying the 532nm laser pulse to change the phase of the upper GeTe layer. We strongly believe that such approach could open new perspectives in all-optically controlled slow-light metamaterials.

  2. Digitally tunable dual wavelength emission from semiconductor ring lasers with filtered optical feedback

    International Nuclear Information System (INIS)

    Khoder, Mulham; Verschaffelt, Guy; Nguimdo, Romain Modeste; Danckaert, Jan; Leijtens, Xaveer; Bolk, Jeroen

    2013-01-01

    We report on a novel integrated approach to obtain dual wavelength emission from a semiconductor laser based on on-chip filtered optical feedback. Using this approach, we show experiments and numerical simulations of dual wavelength emission of a semiconductor ring laser. The filtered optical feedback is realized on-chip by employing two arrayed waveguide gratings to split/recombine light into different wavelength channels. Semiconductor optical amplifiers are placed in the feedback loop in order to control the feedback strength of each wavelength channel independently. By tuning the current injected into each of the amplifiers, we can effectively cancel the gain difference between the wavelength channels due to fabrication and material dichroism, thus resulting in stable dual wavelength emission. We also explore the accuracy needed in the operational parameters to maintain this dual wavelength emission. (letter)

  3. Multicolor tuning towards single red-emission band of upconversion nanoparticles for tunable optical component and optical/x-ray imaging agents via Ce"3"+ doping

    International Nuclear Information System (INIS)

    Yi, Zhigao; Zeng, Tianmei; Xu, Yaru; Qian, Chao; Liu, Hongrong; Zeng, Songjun; Lu, Wei; Hao, Jianhua

    2015-01-01

    A simple strategy of Ce"3"+ doping is proposed to realize multicolor tuning and predominant red emission in BaLnF_5:Yb"3"+/Ho"3"+ (Ln"3"+ = Gd"3"+, Y"3"+, Yb"3"+) systems. A tunable upconversion (UC) multicolor output from green/yellow to red can be readily achieved in a fixed Yb"3"+/Ho"3"+ composition by doping Ce"3"+, providing an effective route for multicolor tuning widely used for various optical components. Moreover, compared with Ce"3"+-free UC nanoparticles (UCNPs), a remarkable enhancement of the red-to-green (R/G) ratio is observed by doping 30% Ce"3"+, arising from the two largely promoted cross-relaxation (CR) processes between Ce"3"+ and Ho"3"+. UCNPs with pure red emission are selected as in vivo UC bioimaging agents, demonstrating the merits of deep penetration depth, the absence of autofluorescence and high contrast in small animal bioimaging. Moreover, such fluorescence imaging nanoprobes can also be used as contrast agents for three-dimensional (3D) x-ray bioimaging by taking advantage of the high K-edge values and x-ray absorption coefficients of Ba"2"+, Gd"3"+, and Ce"3"+ in our designed nanoprobes. Thus, the simultaneous realization of multicolor output, highly enhanced R/G ratio, and predominant red emission makes the Ce"3"+-doped UCNPs very useful for widespread applications in optical components and bioimaging. (paper)

  4. Multicolor tuning towards single red-emission band of upconversion nanoparticles for tunable optical component and optical/x-ray imaging agents via Ce(3+) doping.

    Science.gov (United States)

    Yi, Zhigao; Zeng, Tianmei; Xu, Yaru; Lu, Wei; Qian, Chao; Liu, Hongrong; Zeng, Songjun; Hao, Jianhua

    2015-09-25

    A simple strategy of Ce(3+) doping is proposed to realize multicolor tuning and predominant red emission in BaLnF5:Yb(3+)/Ho(3+) (Ln(3+) = Gd(3+), Y(3+), Yb(3+)) systems. A tunable upconversion (UC) multicolor output from green/yellow to red can be readily achieved in a fixed Yb(3+)/Ho(3+) composition by doping Ce(3+), providing an effective route for multicolor tuning widely used for various optical components. Moreover, compared with Ce(3+)-free UC nanoparticles (UCNPs), a remarkable enhancement of the red-to-green (R/G) ratio is observed by doping 30% Ce(3+), arising from the two largely promoted cross-relaxation (CR) processes between Ce(3+) and Ho(3+). UCNPs with pure red emission are selected as in vivo UC bioimaging agents, demonstrating the merits of deep penetration depth, the absence of autofluorescence and high contrast in small animal bioimaging. Moreover, such fluorescence imaging nanoprobes can also be used as contrast agents for three-dimensional (3D) x-ray bioimaging by taking advantage of the high K-edge values and x-ray absorption coefficients of Ba(2+), Gd(3+), and Ce(3+) in our designed nanoprobes. Thus, the simultaneous realization of multicolor output, highly enhanced R/G ratio, and predominant red emission makes the Ce(3+)-doped UCNPs very useful for widespread applications in optical components and bioimaging.

  5. Wet/dry film thickness measurement of paint by absorption spectroscopy with acousto-optic tunable filter spectrometer

    Science.gov (United States)

    Sinha, Pranay G.; Xiong, Xiangchun; Jin, Feng; Trivedi, Sudhir; Prasad, Narashima S.

    2005-08-01

    Controlling/monitoring the thickness of applied paint in real time is important to many situations including painting ship and submarine hulls in dry docks for maintaining health of ships and submarines against the harshness of the sea, in automobile and aerospace industries, and in a variety of other industries as a control sensor that plays significant role in product quality, process control, and cost control. Insufficient thickness results to inadequate protection while overspray leads to waste and pollution of the environment. A rugged instrumentation for the real time non-contact accurate measurement of wet and dry paint film thickness measurement will be immensely valuable. As paint is applied with several layers of the same or different type, thickness of each newly sprayed wet layer is of most interest, but measurement on dry paint is also useful. In this study, we use acousto-optic tunable filter-based near infrared spectrometer to obtain the absorption spectrum of layers of paint sprayed on sand blasted steel surface and thus measure the thickness of coating under both wet and dry situations. NIR spectra are obtained from 1100 to 2300 nm on four sample of different thickness of paint up to 127 micron. Partial least squares model built with the spectra shows good correlation with standard error of prediction within ~ 0.7 micron. Results indicate that the spectra also respond to the amount of organic solvent in the wet paint and can be used to monitor the degree of dryness of the paint in real time.

  6. A Fiber Optic PD Sensor Using a Balanced Sagnac Interferometer and an EDFA-Based DOP Tunable Fiber Ring Laser

    Science.gov (United States)

    Wang, Lutang; Fang, Nian; Wu, Chunxu; Qin, Haijuan; Huang, Zhaoming

    2014-01-01

    A novel fiber-optic acoustic sensor using an erbium-doped fiber amplifier (EDFA)-based fiber ring laser and a balanced Sagnac interferometer for acoustic sensing of the partial discharge (PD) in power transformers is proposed and demonstrated. As a technical background, an experimental investigation on how the variations of the fiber birefringence affect the sensor performances was carried out, and the results are discussed. The operation principles are described, and the relevant formulas are derived. The analytical results show that an EDFA-based fiber ring laser operating in chaotic mode can provide a degree of polarization (DOP) tunable light beam for effectively suppressing polarization fading noises. The balanced Sagnac interferometer can eliminate command intensity noises and enhance the signal-to-noise ratio (SNR). Furthermore, it inherently operates at the quadrature point of the response curve without any active stabilizations. Several experiments are conducted for evaluating the performances of the sensor system, as well as for investigating the ability of the detection of high-frequency acoustic emission signals. The experimental results demonstrate that the DOP of the laser beam can be continuously tuned from 0.2% to 100%, and the power fluctuation in the whole DOP tuning range is less than 0.05 dBm. A high-frequency response up to 300 kHz is reached, and the high sensing sensitivity for detections of weak corona discharges, as well as partial discharges also is verified. PMID:24824371

  7. Highly crystalline p-PbS thin films with tunable optical and hole transport parameters by chemical bath deposition

    International Nuclear Information System (INIS)

    Bai, Rekha; Kumar, Dinesh; Chaudhary, Sujeet; Pandya, Dinesh K.

    2017-01-01

    Lead sulfide (PbS) thin films, consisting of well faceted (up to 400 nm) cubic-nanocrystals and possessing significantly improved opto-electronic parameters essential for photovoltaic applications, are grown by utilizing chemical bath deposition (CBD) technique with bath concentrations of 10–200 mM. X-ray diffraction (XRD) and Raman studies confirm the highly crystalline and pure phase of PbS. FESEM and HRTEM studies show that all the films possess uniform and compact (111) oriented nanocubic morphology. Bath concentration change provides tunability of nanocube size from 100 to 400 nm and the direct optical band gap from 1.50 to 0.94 eV. The PbS films exhibit p-type semiconducting behavior with hitherto unreported concurrent highest mobility of 29.3 cm"2V"−"1s"−"1 and high carrier concentration of ∼10"1"8 cm"−"3 with the lowest room temperature resistivity of 0.26 Ω–cm. The 25 mM and 10 mM films show significant surface plasmon absorption in 1200–2400 nm range making them suitable as efficient infrared absorbers in excitonic and multi-junction solar cells.

  8. Identification and tunable optical coherent control of transition-metal spins in silicon carbide

    NARCIS (Netherlands)

    Bosma, Tom; Lof, Gerrit J. J.; Gilardoni, Carmem M.; Zwier, Olger V.; Hendriks, Freddie; Ellison, Alexandre; Magnusson, Björn; Gällström, Andreas; Ivanov, Ivan G.; Son, N. T.; Havenith, Remco W. A.; Wal, Caspar H. van der

    2018-01-01

    Color centers in wide-bandgap semiconductors are attractive systems for quantum technologies since they can combine long-coherent electronic spin and bright optical properties. Several suitable centers have been identified, most famously the nitrogen-vacancy defect in diamond. However, integration

  9. [Testing method research for key performance indicator of imaging acousto-optic tunable filter (AOTF)].

    Science.gov (United States)

    Hu, Shan-Zhou; Chen, Fen-Fei; Zeng, Li-Bo; Wu, Qiong-Shui

    2013-01-01

    Imaging AOTF is an important optical filter component for new spectral imaging instruments developed in recent years. The principle of imaging AOTF component was demonstrated, and a set of testing methods for some key performances were studied, such as diffraction efficiency, wavelength shift with temperature, homogeneity in space for diffraction efficiency, imaging shift, etc.

  10. Rapidly tunable continuous-wave optical parametric oscillator pumped by a fiber laser

    NARCIS (Netherlands)

    Klein, M.E.; Gross, P.; Boller, Klaus J.; Auerbach, M.; Wessels, P.; Fallnich, C.

    2003-01-01

    We report on rapid, all-electronically controlled wavelength tuning of a continuous-wave (cw) optical parametric oscillator (OPO) pumped by an ytterbium fiber laser. The OPO is singly resonant for the signal wave and consists of a 40-mm-long periodically poled lithium niobate crystal in a

  11. Measurement of IR optics with linear coupling's action-angle parametrization

    Science.gov (United States)

    Luo, Y.; Bai, M.; Pilat, F.; Satogata, T.; Trbojevic, D.

    2005-08-01

    Linear coupling’s action-angle parametrization is convenient for interpretation of turn-by-turn beam position monitor (BPM) data. We demonstrate how to apply this parametrization to extract Twiss and coupling parameters in interaction regions (IRs), using BPMs on each side of a long IR drift region. Example data were acquired at the Relativistic Heavy Ion Collider, using an ac dipole to excite a single transverse eigenmode. We have measured the waist of the β function and its Twiss and coupling parameters.

  12. Measurement of IR optics with linear coupling’s action-angle parametrization

    Directory of Open Access Journals (Sweden)

    Y. Luo

    2005-08-01

    Full Text Available Linear coupling’s action-angle parametrization is convenient for interpretation of turn-by-turn beam position monitor (BPM data. We demonstrate how to apply this parametrization to extract Twiss and coupling parameters in interaction regions (IRs, using BPMs on each side of a long IR drift region. Example data were acquired at the Relativistic Heavy Ion Collider, using an ac dipole to excite a single transverse eigenmode. We have measured the waist of the β function and its Twiss and coupling parameters.

  13. Flexible transparent aerogels as window retrofitting films and optical elements with tunable birefringence

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qingkun; Frazier, Allister W.; Zhao, Xinpeng; De La Cruz, Joshua A.; Hess, Andrew J.; Yang, Ronggui; Smalyukh, Ivan I.

    2018-06-01

    Experimental realization of optically transparent, mechanically robust and flexible aerogels has been a longstanding challenge, which limits their practical applications in energy-saving devices, such as thermally insulating films for enhancing energy efficiency of windows. The poor transparency precluded even hypothetical consideration of the possibility of birefringent aerogels. We develop birefringent and optically isotropic aerogels that combine properties of thermal super-insulation, mechanical robustness and flexibility, and transparency to visible-spectrum light. This unusual combination of physical properties is achieved by combining liquid crystalline self-organization of cellulose nanofibers with polysiloxane cross-linking and control of the nanoscale porosity to form hybrid organic-inorganic mesostructured aerogels. Potential applications of these inexpensive materials range from single pane window retrofitting to smart fabrics.

  14. Shape-controlled synthesis of organolead halide perovskite nanocrystals and their tunable optical absorption

    International Nuclear Information System (INIS)

    Chen, Zhenhua; Tang, Yongbing; Huang, Xing; Lee, Chun-Sing; Li, Hui; Ho, Derek

    2014-01-01

    Hybrid organolead halide perovskites (CH 3 NH 3 PbI 3 ) with polymorphic structures have been successfully synthesized by controlling their solubility in solvents with different polarities. Crystal formation stages of the perovskites have been demonstrated for the first time. Shape changes of such perovskites are accompanied by transition in their crystal structures and variation of optical properties. Herein, a new trigonal phase for CH 3 NH 3 PbI 3 has been observed with a rod-like morphology. Photoemission study indicates a significant red shift in the perovskite nanoparticles, compared to that of the rod-like nanocrystals. This solvent-controlled formation of polymorphic phases provide an additional approach for controlling the optical properties of CH 3 NH 3 PbI 3 for various optoelectronic applications. (papers)

  15. Error Measurements in an Acousto-Optic Tunable Filter Fiber Bragg Grating Sensor System

    Science.gov (United States)

    1994-05-01

    for an ideal AOTF, at 833 and 838 nm using a TeO2 crystal ............................ 33 Figure 3.12. Frequency characteristics of Equation (3.43...multiple channels in an AOTF requires the presence of multiple RF frequencies to establish the complex grating. Since the crystal used in the AOTF ( TeO2 ) is...in germano- silicate glass . This index modulation, Bragg grating, acts as an optical band rejection filter for those wavelengths that meet the Bragg

  16. Measurement of the Shape of the Optical-IR Spectrum of Prompt Emission from Gamma-Ray Bursts

    Science.gov (United States)

    Grossan, Bruce; Kistaubayev, M.; Smoot, G.; Scherr, L.

    2017-06-01

    While the afterglow phase of gamma-ray bursts (GRBs) has been extensively measured, detections of prompt emission (i.e. during bright X-gamma emission) are more limited. Some prompt optical measurements are regularly made, but these are typically in a single wide band, with limited time resolution, and no measurement of spectral shape. Some models predict a synchrotron self-absorption spectral break somewhere in the IR-optical region. Measurement of the absorption frequency would give extensive information on each burst, including the electron Lorentz factor, the radius of emission, and more (Shen & Zhang 2008). Thus far the best prompt observations have been explained invoking a variety of models, but often with a non-unique interpretation. To understand this apparently heterogeneous behavior, and to reduce the number of possible models, it is critical to add data on the optical - IR spectral shape.Long GRB prompt X-gamma emission typically lasts ~40-80 s. The Swift BAT instrument rapidly measures GRB positions to within a few arc minutes and communicates them via the internet within a few seconds. We have measured the time for a fast-moving D=700 mm telescope to point and settle to be less than 9 s anywhere on the observable sky. Therefore, the majority of prompt optical-IR emission can be measured responding to BAT positions with this telescope. In this presentation, we describe our observing and science programs, and give our design for the Burst Simultaneous Three-channel Instrument (BSTI), which uses dichroics to send eparate bands to 3 cameras. Two EMCCD cameras, give high-time resolution in B and V; a third camera with a HgCdTe sensor covers H band, allowing us to study extinguished bursts. For a total exposure time of 10 s, we find a 5 sigma sensitivity of 21.3 and 20.3 mag in B and R for 1" seeing and Kitt Peak sky brightness, much fainter than typical previous prompt detections. We estimate 5 sigma H-band sensitivity for an IR optimized telescope to be

  17. Non-Linear Optical Studies of IR Materials with Infrared Femtosecond Laser

    Science.gov (United States)

    2016-12-15

    chemical/bio weapon signatures in real time. • IR sources and detectors have a wide ranging applications in public sector from night vision cameras on cars...Jeffrey D. Bude, Andy J. Bayramian, Christopher D. Marshall, Thomas M. Spinka, Constantin L. Haefner, Test station development for laser-induced

  18. Tunable negative-tap photonic microwave filter based on a cladding-mode coupler and an optically injected laser of large detuning.

    Science.gov (United States)

    Chan, Sze-Chun; Liu, Qing; Wang, Zhu; Chiang, Kin Seng

    2011-06-20

    A tunable negative-tap photonic microwave filter using a cladding-mode coupler together with optical injection locking of large wavelength detuning is demonstrated. Continuous and precise tunability of the filter is realized by physically sliding a pair of bare fibers inside the cladding-mode coupler. Signal inversion for the negative tap is achieved by optical injection locking of a single-mode semiconductor laser. To couple light into and out of the cladding-mode coupler, a pair of matching long-period fiber gratings is employed. The large bandwidth of the gratings requires injection locking of an exceptionally large wavelength detuning that has never been demonstrated before. Experimentally, injection locking with wavelength detuning as large as 27 nm was achieved, which corresponded to locking the 36-th side mode. Microwave filtering with a free-spectral range tunable from 88.6 MHz to 1.57 GHz and a notch depth larger than 35 dB was obtained.

  19. Near-infrared light-controlled tunable grating based on graphene/elastomer composites

    Science.gov (United States)

    Wang, Fei; Jia, Shuhai; Wang, Yonglin; Tang, Zhenhua

    2018-02-01

    A near-infrared (nIR) light actuated tunable transmission optical grating based on graphene nanoplatelet (GNP)/polydimethylsiloxane (PDMS) and PDMS is proposed. A simple fabrication protocol is studied that allows integration of the grating with the actuation mechanism; both components are made from soft elastomers, and this ensure the tunability and the light-driven operation of the grating. The resulting grating structure demonstrates continuous period tunability of 2.7% under an actuation power density of 220 mW cm-2 within a period of 3 s and also demonstrates a time-independent characteristic. The proposed infrared activated grating can be developed for wireless remote light splitting in bio/chemical sensing and optical telecommunications applications.

  20. Narrow linewidth pulsed optical parametric oscillator

    Indian Academy of Sciences (India)

    also because of high laser damage threshold coating on mirror as well as on crystal. Now-a-days with the development of coating technology and with the availability of good optical quality crystals having high damage threshold and deep infrared. (IR) transparency it is possible to extend the tunability of the OPO.

  1. Temperature-agile and structure-tunable optical properties of VO2/Ag thin films

    International Nuclear Information System (INIS)

    Zhang, X.R.; Hu, X.; Wang, W.; Zhao, Y.; Reinhardt, K.; Knize, R.J.; Lu, Yalin

    2012-01-01

    By integrating together VO 2 's unique near-room-temperature (RT) semiconductor-metal (S-M) phase transition with a thin silver (Ag) layer's plasmonic properties, VO 2 /Ag multilayers could present a much enhanced optical transmission change when increasing the temperature from RT to over VO 2 's S-M phase-transition temperature. Changing VO 2 and Ag layer thicknesses can also significantly tune their transmission and absorption properties, which could lead to a few useful designs in optoelectronic and energy-saving industries. (orig.)

  2. Tunable nano-wrinkling of chiral surfaces: Structure and diffraction optics

    International Nuclear Information System (INIS)

    Rofouie, P.; Rey, A. D.; Pasini, D.

    2015-01-01

    Periodic surface nano-wrinkling is found throughout biological liquid crystalline materials, such as collagen films, spider silk gland ducts, exoskeleton of beetles, and flower petals. These surface ultrastructures are responsible for structural colors observed in some beetles and plants that can dynamically respond to external conditions, such as humidity and temperature. In this paper, the formation of the surface undulations is investigated through the interaction of anisotropic interfacial tension, swelling through hydration, and capillarity at free surfaces. Focusing on the cellulosic cholesteric liquid crystal (CCLC) material model, the generalized shape equation for anisotropic interfaces using the Cahn-Hoffman capillarity vector and the Rapini-Papoular anchoring energy are applied to analyze periodic nano-wrinkling in plant-based plywood free surfaces with water-induced cholesteric pitch gradients. Scaling is used to derive the explicit relations between the undulations’ amplitude expressed as a function of the anchoring strength and the spatially varying pitch. The optical responses of the periodic nano-structured surfaces are studied through finite difference time domain simulations indicating that CCLC surfaces with spatially varying pitch reflect light in a wavelength higher than that of a CCLC’s surface with constant pitch. This structural color change is controlled by the pitch gradient through hydration. All these findings provide a foundation to understand structural color phenomena in nature and for the design of optical sensor devices

  3. Tunable nano-wrinkling of chiral surfaces: Structure and diffraction optics

    Energy Technology Data Exchange (ETDEWEB)

    Rofouie, P.; Rey, A. D., E-mail: alejandro.rey@mail.mcgill.ca [Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2 (Canada); Pasini, D. [Department of Mechanical Engineering, McGill University, 817 Sherbrook West, Montreal, Quebec H3A 0C3 (Canada)

    2015-09-21

    Periodic surface nano-wrinkling is found throughout biological liquid crystalline materials, such as collagen films, spider silk gland ducts, exoskeleton of beetles, and flower petals. These surface ultrastructures are responsible for structural colors observed in some beetles and plants that can dynamically respond to external conditions, such as humidity and temperature. In this paper, the formation of the surface undulations is investigated through the interaction of anisotropic interfacial tension, swelling through hydration, and capillarity at free surfaces. Focusing on the cellulosic cholesteric liquid crystal (CCLC) material model, the generalized shape equation for anisotropic interfaces using the Cahn-Hoffman capillarity vector and the Rapini-Papoular anchoring energy are applied to analyze periodic nano-wrinkling in plant-based plywood free surfaces with water-induced cholesteric pitch gradients. Scaling is used to derive the explicit relations between the undulations’ amplitude expressed as a function of the anchoring strength and the spatially varying pitch. The optical responses of the periodic nano-structured surfaces are studied through finite difference time domain simulations indicating that CCLC surfaces with spatially varying pitch reflect light in a wavelength higher than that of a CCLC’s surface with constant pitch. This structural color change is controlled by the pitch gradient through hydration. All these findings provide a foundation to understand structural color phenomena in nature and for the design of optical sensor devices.

  4. Gate-tunable gigantic changes in lattice parameters and optical properties in VO2

    Science.gov (United States)

    Nakano, Masaki; Okuyama, Daisuke; Shibuya, Keisuke; Ogawa, Naoki; Hatano, Takafumi; Kawasaki, Masashi; Arima, Taka-Hisa; Iwasa, Yoshihiro; Tokura, Yoshinori

    2014-03-01

    The field-effect transistor provides an electrical switching function of current flowing through a channel surface by external gate voltage (VG). We recently reported that an electric-double-layer transistor (EDLT) based on vanadium dioxide (VO2) enables electrical switching of the metal-insulator phase transition, where the low-temperature insulating state can be completely switched to the metallic state by application of VG. Here we demonstrate that VO2-EDLT enables electrical switching of lattice parameters and optical properties as well as electrical current. We performed in-situ x-ray diffraction and optical transmission spectroscopy measurements, and found that the c-axis length and the infrared transmittance of VO2 can be significantly modulated by more than 1% and 40%, respectively, by application of VG. We emphasize that these distinguished features originate from the electric-field induced bulk phase transition available with VO2-EDLT. This work was supported by the Japan Society for the Promotion of Science (JSPS) through its ``Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program).''

  5. Forbidden optical transition in Ti-like Xe, Ba, and Ir

    International Nuclear Information System (INIS)

    Bekker, H.; Windberger, A.; Binder, M.; López-Urrutia, J. R. Crespo; Versolato, O. O.; Klawitter, R.

    2015-01-01

    We present measurements of the (3d 4 ) 5 D 2 − 5 D 3 transitions in the Ti-like ions Xe 32+ , Ba 34+ , and Ir 55+ produced and trapped in the Heidelberg electron beam ion trap. The obtained wavelengths have a precision at the few ppm-level and are thereby the most precise measurements of these transitions up to date. For Z=60−75 semi-empirical calculations have shown excellent agreement, however our measurements combined with data from other works shows that outside this range predictions quickly deviate. The value obtained for Ir 55+ 357.434(2) nm confirms the linear mismatch to ab initio calculations for Z > 70, as hypothesized in Utter et al., Phys. Rev. A 67, 012508 (2003)

  6. Ge22As20Se58 glass ultrafast laser inscribed waveguides for mid-IR integrated optics

    DEFF Research Database (Denmark)

    Morris, James M.; Mackenzie, Mark D.; Petersen, Christian Rosenberg

    2018-01-01

    Ultrafast laser inscription has been used to produce channel waveguides in Ge22As20Se58 glass (GASIR-1, Umicore N.V). The mode field diameter and waveguide losses at 2.94 mu m were measured along with the waveguide dispersion in the 1 to 4.5 mu m range, which is used to estimate the zero-dispersi...... ultrafast laser inscribed waveguide devices in GASIR-1 for mid-IR integrated optics applications. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.......Ultrafast laser inscription has been used to produce channel waveguides in Ge22As20Se58 glass (GASIR-1, Umicore N.V). The mode field diameter and waveguide losses at 2.94 mu m were measured along with the waveguide dispersion in the 1 to 4.5 mu m range, which is used to estimate the zero......-dispersion wavelength. Z-scan measurements of bulk samples have also been performed to determine the nonlinear refractive index. Finally, midIR supercontinuum generation has been shown when pumping the waveguides with femtosecond pulses centered at 4.6 mu m. Supercontinuum spanning approximately 4 mu m from 2.5 to 6...

  7. High-z X-ray Obscured Quasars in Galaxies with Extreme Mid-IR/Optical Colors

    Science.gov (United States)

    Piconcelli, E.; Lanzuisi, G.; Fiore, F.; Feruglio, C.; Vignali, C.; Salvato, M.; Grappioni, C.

    2009-05-01

    Extreme Optical/Mid-IR color cuts have been used to uncover a population of dust-enshrouded, mid-IR luminous galaxies at high redshifts. Several lines of evidence point towards the presence of an heavily absorbed, possibly Compton-thick quasar at the heart of these systems. Nonetheless, the X-ray spectral properties of these intriguing sources still remain largely unexplored. Here we present an X-ray spectroscopic study of a large sample of 44 extreme dust-obscured galaxies (EDOGs) with F24 μm/FR>2000 and F24 μm>1.3 mJy selected from a 6 deg2 region in the SWIRE fields. The application of our selection criteria to a wide area survey has been capable of unveiling a population of X-ray luminous, absorbed z>1 quasars which is mostly missed in the traditional optical/X-ray surveys performed so far. Advances in the understanding of the X-ray properties of these recently-discovered sources by Simbol-X observations will be also discussed.

  8. Anharmonic effects in IR, Raman, and Raman optical activity spectra of alanine and proline zwitterions

    Czech Academy of Sciences Publication Activity Database

    Daněček, Petr; Kapitán, Josef; Baumruk, V.; Bednárová, Lucie; Kopecký, V.; Bouř, Petr

    2007-01-01

    Roč. 126, č. 22 (2007), s. 224513-1 ISSN 0021-9606 R&D Projects: GA ČR GA203/06/0420; GA ČR GA202/07/0732; GA AV ČR IAA400550702 Institutional research plan: CEZ:AV0Z40550506 Keywords : IR * Raman * ROA spectra * Anharmonic effects Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.044, year: 2007

  9. Optical properties of wet paper and simulation of the effect of autoprofiling on gas-fired IR drying

    Energy Technology Data Exchange (ETDEWEB)

    Ojala, K T; Lampinen, M J [Helsinki University of Technology (FI)

    1991-12-01

    Mathematical models are developed to determine the radiative heat transfer of gas-fired infrared dryers. These models are based on the calculation of radiation energy balance between the main surfaces and layers in the dryer section. The energy efficiency can be calculated, when the temperatures of the radiator and the optical properties of all parts of the dryer are known. A computer program is used for studying the autoprofiling effect in gas-fired infrared drying. Optical properties of paper samples of different moisture contents as a function of wavelength are systematically measured by using FT-IR spectrometer and integrating sphere techniques. These measurements covered the moisture content range of 6-150%. The total measured wavelength range is 1.0-20.0 {mu}m. The moisture content of paper increases the absorptivity mainly in two wavelength ranges, i.e. 1.4-2.6 {mu}m and 3.75-6.0 {mu}m. In these ranges, the difference between the absorptivity of two sheets (dry weight 41.1 g/m{sup 2}, moisture contents 6.0% and 20.8%) is 5-10%. Outside these ranges, the difference is less than 5%. The radiation properties of component surfaces of the IR dryer were measured or taken from literature. The dryer efficiency as a function of the moisture content of paper is calculated. The extent of the autoprofilling effect in gas-fired IR drying is hereby achieved for light weight coated paper web. In one simulation, before the dryer, the moisture difference between two sheets was 5.0% (=20% - 15%). After the dryer, the moisture difference was reduced to 4.5%. If the variation in moisture contents is high, the autoprofilling effect takes place and reduces the moisture variaton. (AB).

  10. APPLIED OPTICS. Voltage-tunable circular photogalvanic effect in silicon nanowires.

    Science.gov (United States)

    Dhara, Sajal; Mele, Eugene J; Agarwal, Ritesh

    2015-08-14

    Electronic bands in crystals can support nontrivial topological textures arising from spin-orbit interactions, but purely orbital mechanisms can realize closely related dynamics without breaking spin degeneracies, opening up applications in materials containing only light elements. One such application is the circular photogalvanic effect (CPGE), which is the generation of photocurrents whose magnitude and polarity depend on the chirality of optical excitation. We show that the CPGE can arise from interband transitions at the metal contacts to silicon nanowires, where inversion symmetry is locally broken by an electric field. Bias voltage that modulates this field further controls the sign and magnitude of the CPGE. The generation of chirality-dependent photocurrents in silicon with a purely orbital-based mechanism will enable new functionalities in silicon that can be integrated with conventional electronics. Copyright © 2015, American Association for the Advancement of Science.

  11. Scalable nanofabrication of U-shaped nanowire resonators with tunable optical magnetism.

    Science.gov (United States)

    Zhou, Fan; Wang, Chen; Dong, Biqin; Chen, Xiangfan; Zhang, Zhen; Sun, Cheng

    2016-03-21

    Split ring resonators have been studied extensively in reconstituting the diminishing magnetism at high electromagnetic frequencies in nature. However, breakdown in the linear scaling of artificial magnetism is found to occur at the near-infrared frequency mainly due to the increasing contribution of self-inductance while reducing dimensions of the resonators. Although alternative designs have enabled artificial magnetism at optical frequencies, their sophisticated configurations and fabrication procedures do not lend themselves to easy implementation. Here, we report scalable nanofabrication of U-shaped nanowire resonators (UNWRs) using the high-throughput nanotransfer printing method. By providing ample area for conducting oscillating electric current, UNWRs overcome the saturation of the geometric scaling of the artificial magnetism. We experimentally demonstrated coarse and fine tuning of LC resonances over a wide wavelength range from 748 nm to 1600 nm. The added flexibility in transferring to other substrates makes UNWR a versatile building block for creating functional metamaterials in three dimensions.

  12. Tunable CsPbBr3/Cs4PbBr6 phase transformation and their optical spectroscopic properties.

    Science.gov (United States)

    Chen, Xiao; Chen, Daqin; Li, Junni; Fang, Gaoliang; Sheng, Hongchao; Zhong, Jiasong

    2018-04-24

    As a novel type of promising materials, metal halide perovskites are a rising star in the field of optoelectronics. On this basis, a new frontier of zero-dimensional perovskite-related Cs4PbBr6 with bright green emission and high stability has attracted an enormous amount of attention, even though its photoluminescence still requires to clarification. Herein, the controllable phase transformation between three-dimensional CsPbBr3 and zero-dimensional Cs4PbBr6 is easily achieved in a facile ligand-assisted supersaturated recrystallization synthesis procedure via tuning the amount of surfactants, and their unique optical properties are investigated and compared in detail. Both Cs4PbBr6 and CsPbBr3 produce remarkably intense green luminescence with quantum yields up to 45% and 80%, respectively; however, significantly different emitting behaviors are observed. The fluorescence lifetime of Cs4PbBr6 is much longer than that of CsPbBr3, and photo-blinking is easily detected in the Cs4PbBr6 product, proving that the zero-dimensional Cs4PbBr6 is indeed a highly luminescent perovskite-related material. Additionally, for the first time, tunable emissions over the visible-light spectral region are demonstrated to be achievable via halogen composition modulations in the Cs4PbX6 (X = Cl, Br, I) samples. Our study brings a simple method for the phase control of CsPbBr3/Cs4PbBr6 and demonstrates the intrinsic luminescence nature of the zero-dimensional perovskite-related Cs4PbX6 products.

  13. Synchronous optical packet switch architecture with tunable single and multi-channels wavelength converters

    Science.gov (United States)

    Hamza, Haitham S.; Adel, Reham

    2017-07-01

    In this paper, we propose a bufferless synchronous optical packet switch (OPS) architecture named the Limited-range wavelength conversion with Dynamic Pump-wavelength Selection (LDPS) architecture. LDPS is equipped with a dedicated limited-range wavelength converters (LRWCs, and a shared pool of parametric wavelength converters (PWCs) with dynamic pump-wavelength selection (DPS). The adoption of hybrid conversion types in the proposed architecture aims at improving the packet loss rate (PLR) compared to conventional architecture with single conversion types, while reducing (or at least maintaining) the conversion distance (d) of used wavelength converters. Packet contention in the proposed architecture is resolved using the first available algorithm (FAA) and the dynamic pump-wavelength selection algorithm (DPSA). The performance of the proposed architecture is compared to two well-known conventional architectures; namely, the LRWC architecture that uses dedicated LRWCS for each input wavelength, and the DPS architecture that uses a shared pool of dynamic pump-wavelength converters (PWCs). Simulation results show that, for the same value of d, the new architecture reduces the PLR compared to the LRWC architecture by up to 40 % and 99.7 % for traffic loads, 0.5 and 1; respectively. In addition, for d = 1 , the new architecture reduces the PLR compared to the DPS architecture by up to 10 % and 99.3 % for traffic loads, 0.5 and 1; respectively.

  14. Enhanced and tunable optical quantum efficiencies from plasmon bandwidth engineering in bimetallic CoAg nanoparticles

    Directory of Open Access Journals (Sweden)

    A. Malasi

    2016-10-01

    Full Text Available Plasmonic nanoparticles are amongst the most effective ways to resonantly couple optical energy into and out of nanometer sized volumes. However, controlling and/or tuning the transfer of this incident energy to the surrounding near and far field is one of the most interesting challenges in this area. Due to the dielectric properties of metallic silver (Ag, its nanoparticles have amongst the highest radiative quantum efficiencies (η, i.e., the ability to radiatively transfer the incident energy to the surrounding. Here we report the discovery that bimetallic nanoparticles of Ag made with immiscible and plasmonically weak Co metal can show comparable and/or even higher η values. The enhancement is a result of the narrowing of the plasmon bandwidth from these bimetal systems. The phenomenological explanation of this effect based on the dipolar approximation points to the reduction in radiative losses within the Ag nanoparticles when in contact with cobalt. This is also supported by a model of coupling between poor and good conductors based on the surface to volume ratio. This study presents a new type of bandwidth engineering, one based on using bimetal nanostructures, to tune and/or enhance the quality factor and quantum efficiency for near and far-field plasmonic applications.

  15. Periodic refractive index modifications inscribed in polymer optical fibre by focussed IR femtosecond pulses

    DEFF Research Database (Denmark)

    Stecher, Matthias; Williams, Robert J.; Bang, Ole

    Focussed femtosecond laser pulses were used to inscribe a periodic array of modifications in the core of a polymer optical fibre. Structural and refractive-index modifications have been observed at different pulse energies using DIC microscopy.......Focussed femtosecond laser pulses were used to inscribe a periodic array of modifications in the core of a polymer optical fibre. Structural and refractive-index modifications have been observed at different pulse energies using DIC microscopy....

  16. Optical properties of wet paper and simulation of the effect of autoprofiling on gas-fired IR drying

    Energy Technology Data Exchange (ETDEWEB)

    Ojala, K T; Lampinen, M J

    1991-01-01

    We have developed new models to determine the radiative heat transfer of gas-fired infrared dryers. A computer program based on the mathematical models is developed further. This program is used for studying the autoprofiling effect in gas-fired infrared drying. Optical properties of paper samples of different moisture contents as a function of wavelength are systematically measured by using FT-lR specrometer and integraing sphere techniques. These measurements covered the moisture content range of 6- 150 %. A new wavelength range (1.2- 1.9 mm), not properly covered by our earlier measurements, is measured by using a liquid nitrogen cooled detector. The total measured wavelength range is 1.0-20.0 mm. The moisture dependence of the optical properties of coating are calculated by using a theoretical model developed in State Research Centre of Finland, Laboratory of Optoelectronics. The radiation properties of component surfaces of the IR dryer were either measured or taken from literature. The mathematical models are based on the calculation of radiation energy balance between the main surfaces and layers in the dryer section. The energy efficiency can be calculated, when the temperatures of the radiator and the optical properties of all parts of the dryer are known. A computer program based on the models is developed further. The dryer efficiency as a function of the moisture content of paper is calculated. The extent of the autoprofiling effect in gas-fired IR drying is hereby achieved for light weight coated paper web. If the variation in moisture contents is high, the autoprofiling effect takes place and reduces the moisture variation. However, if the moisture variation is low, it is not a very significant phenomenon. The simulation results are compared to a pilot coater trial made in Cenre Technique du Papier, Grenoble.

  17. Tunable, continuous-wave, ultraviolet source based on intracavity sum-frequency-generation in an optical parametric oscillator using BiB₃O₆.

    Science.gov (United States)

    Devi, Kavita; Kumar, S Chaitanya; Ebrahim-Zadeh, M

    2013-10-21

    We report a continuous-wave (cw) source of tunable radiation across 333-345 nm in the ultraviolet (UV) using bismuth triborate, BiB₃O₆ (BIBO) as the nonlinear gain material. The source is based on internal sum-frequency-generation (SFG) in a cw singly-resonant optical parametric oscillator (OPO) pumped at 532 nm. The compact tunable source employs a 30-mm-long MgO:sPPLT crystal as the OPO gain medium and a 5-mm-long BIBO crystal for intracavity SFG of the signal and pump, providing up to 21.6 mW of UV power at 339.7 nm, with >15 mW over 64% of the SFG tuning range. The cw OPO is also tunable across 1158-1312 nm in the idler, delivering as much as 1.7 W at 1247 nm, with >1W over 65% of the tuning range. The UV output at maximum power exhibits passive power stability better than 3.4% rms and frequency stability of 193 GHz over more than one minute.

  18. Optical fingerprints of solid-liquid interfaces: a joint ATR-IR and first principles investigation

    Science.gov (United States)

    Yang, L.; Niu, F.; Tecklenburg, S.; Pander, M.; Nayak, S.; Erbe, A.; Wippermann, S.; Gygi, F.; Galli, G.

    Despite the importance of understanding the structural and bonding properties of solid-liquid interfaces for a wide range of (photo-)electrochemical applications, there are presently no experimental techniques available to directly probe the microscopic structure of solid-liquid interfaces. To develop robust strategies to interpret experiments and validate theory, we carried out attenuated total internal reflection (ATR-IR) spectroscopy measurements and ab initio molecular dynamics (AIMD) simulations of the vibrational properties of interfaces between liquid water and well-controlled prototypical semiconductor substrates. We show the Ge(100)/H2O interface to feature a reversible potential-dependent surface phase transition between Ge-H and Ge-OH termination. The Si(100)/H2O interface is proposed as a model system for corrosion and oxidation processes. We performed AIMD calculations under finite electric fields, revealing different pathways for initial oxidation. These pathways are predicted to exhibit unique spectral signatures. A significant increase in surface specificity can be achieved utilizing an angle-dependent ATR-IR experiment, which allows to detect such signatures at the interfacial layer and consequently changes in the hydrogen bond network. Funding from DOE-BES Grant No. DE-SS0008939 and the Deutsche Forschungsgemeinschaft (RESOLV, EXC 1069) are gratefully acknowledged.

  19. Synthesis and characterization of near IR fluorescent albumin nanoparticles for optical detection of colon cancer

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Sarit; Pellach, Michal [Department of Chemistry, Bar-Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900 (Israel); Kam, Yossi [Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, P.O. Box 12065, Jerusalem 91120 (Israel); Grinberg, Igor; Corem-Salkmon, Enav [Department of Chemistry, Bar-Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900 (Israel); Rubinstein, Abraham [Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, P.O. Box 12065, Jerusalem 91120 (Israel); Margel, Shlomo, E-mail: shlomo.margel@mail.biu.ac.il [Department of Chemistry, Bar-Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900 (Israel)

    2013-03-01

    Near IR (NIR) fluorescent human serum albumin (HSA) nanoparticles hold great promise as contrast agents for tumor diagnosis. HSA nanoparticles are considered to be biocompatible, non-toxic and non-immunogenic. In addition, NIR fluorescence properties of these nanoparticles are important for in vivo tumor diagnostics, with low autofluorescence and relatively deep penetration of NIR irradiation due to low absorption of biomatrices. The present study describes the synthesis of new NIR fluorescent HSA nanoparticles, by entrapment of a NIR fluorescent dye within the HSA nanoparticles, which also significantly increases the photostability of the dye. Tumor-targeting ligands such as peanut agglutinin (PNA) and anti-carcinoembryonic antigen antibodies (anti-CEA) were covalently conjugated to the NIR fluorescent albumin nanoparticles, increasing the potential fluorescent signal in tumors with upregulated corresponding receptors. Specific colon tumor detection by the NIR fluorescent HSA nanoparticles was demonstrated in a chicken embryo model and a rat model. In future work we also plan to encapsulate cancer drugs such as doxorubicin within the NIR fluorescent HSA nanoparticles for both colon cancer imaging and therapy. - Highlights: Black-Right-Pointing-Pointer Near IR human serum albumin nanoparticles were synthesized and characterized. Black-Right-Pointing-Pointer Nanoparticles were shown to be physically and chemically stable and photostable. Black-Right-Pointing-Pointer Tumor-targeting ligands were covalently conjugated to the nanoparticles. Black-Right-Pointing-Pointer Specific colon cancer tumor detection was demonstrated in chicken-embryo and rat models.

  20. Synthesis and characterization of near IR fluorescent albumin nanoparticles for optical detection of colon cancer

    International Nuclear Information System (INIS)

    Cohen, Sarit; Pellach, Michal; Kam, Yossi; Grinberg, Igor; Corem-Salkmon, Enav; Rubinstein, Abraham; Margel, Shlomo

    2013-01-01

    Near IR (NIR) fluorescent human serum albumin (HSA) nanoparticles hold great promise as contrast agents for tumor diagnosis. HSA nanoparticles are considered to be biocompatible, non-toxic and non-immunogenic. In addition, NIR fluorescence properties of these nanoparticles are important for in vivo tumor diagnostics, with low autofluorescence and relatively deep penetration of NIR irradiation due to low absorption of biomatrices. The present study describes the synthesis of new NIR fluorescent HSA nanoparticles, by entrapment of a NIR fluorescent dye within the HSA nanoparticles, which also significantly increases the photostability of the dye. Tumor-targeting ligands such as peanut agglutinin (PNA) and anti-carcinoembryonic antigen antibodies (anti-CEA) were covalently conjugated to the NIR fluorescent albumin nanoparticles, increasing the potential fluorescent signal in tumors with upregulated corresponding receptors. Specific colon tumor detection by the NIR fluorescent HSA nanoparticles was demonstrated in a chicken embryo model and a rat model. In future work we also plan to encapsulate cancer drugs such as doxorubicin within the NIR fluorescent HSA nanoparticles for both colon cancer imaging and therapy. - Highlights: ► Near IR human serum albumin nanoparticles were synthesized and characterized. ► Nanoparticles were shown to be physically and chemically stable and photostable. ► Tumor-targeting ligands were covalently conjugated to the nanoparticles. ► Specific colon cancer tumor detection was demonstrated in chicken-embryo and rat models.

  1. Optical changes of dentin in the near-IR as a function of mineral content

    Science.gov (United States)

    Berg, Rhett A.; Simon, Jacob C.; Fried, Daniel; Darling, Cynthia L.

    2017-02-01

    The optical properties of human dentin can change markedly due to aging, friction from opposing teeth, and acute trauma, resulting in the formation of transparent or sclerotic dentin with increased mineral density. The objective of this study was to determine the optical attenuation coefficient of human dentin tissues with different mineral densities in the near-infrared (NIR) spectral regions from 1300-2200 nm using NIR transillumination and optical coherence tomography (OCT). N=50 dentin samples of varying opacities were obtained by sectioning whole extracted teeth into 150 μm transverse sections at the cemento-enamel junction or the apical root. Transillumination images were acquired with a NIR camera and attenuation measurements were acquired at various NIR wavelengths using a NIR sensitive photodiode. Samples were imaged with transverse microradiography (gold standard) in order to determine the mineral density of each sample.

  2. Probing the Diffuse Optical-IR Background with TeV Blazars Detected with the MAGIC Telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Prandini, Elisa [Dipartimento di Fisica e Astronomia “G. Galilei”, University of Padova, Padua (Italy); Domínguez, Alberto [Departamento de Física Atómica, Universidad Complutense, Madrid (Spain); Fallah Ramazani, Vandad [Tuorla observatory, University of Turku, Turku (Finland); Hassan, Tarek [IFAE, The Barcelona Institute of Science and Technology, Bellaterra (Spain); Mazin, Daniel [Max Planck Institute for Physics, Munich (Germany); Institute for Cosmic Ray Research, University of Tokyo, Tokyo (Japan); Moralejo, Abelardo [IFAE, The Barcelona Institute of Science and Technology, Bellaterra (Spain); Nievas Rosillo, Mireia [Departamento de Física Atómica, Universidad Complutense, Madrid (Spain); Vanzo, Gaia; Vazquez Acosta, Monica, E-mail: prandini@pd.infn.it [Instituto de Astrofísica de Canarias, Tenerife (Spain); Departamento de Astrofisica, Universidad de La Laguna, Tenerife (Spain)

    2017-11-22

    Blazars are radio loud quasars whose jet points toward the observer. The observed emission is mostly non-thermal, dominated by the jet emission, and in some cases extends up to the very high energy gamma rays (VHE; E > 100 GeV). To date, more than 60 blazars have been detected at VHE mainly with ground-based imaging atmospheric Cherenkov telescopes (IACTs) such as MAGIC, H.E.S.S., and VERITAS. Energetic photons from a blazar may interact with the diffuse optical and IR background (the extragalactic background light, EBL) leaving an imprint on the blazar energy spectrum. This effect can be used to constrain the EBL, with basic assumptions on the intrinsic energy spectrum. Current generation of IACTs is providing valuable measurements of the EBL density and energy spectrum from optical to infrared frequencies. In this contribution, we present the latest results obtained with the data taken with the MAGIC telescopes: using 32 spectra from 12 blazars, the scale factor of the optical density predicted by the EBL model from Domínguez et al. (2011) is constrained to be 0.95 (+0.11, −0.12){sub stat} (+0.16, −0.07){sub sys}, where a value of 1 means the perfect match with the model.

  3. Probing the Diffuse Optical-IR Background with TeV Blazars Detected with the MAGIC Telescopes

    Directory of Open Access Journals (Sweden)

    Elisa Prandini

    2017-11-01

    Full Text Available Blazars are radio loud quasars whose jet points toward the observer. The observed emission is mostly non-thermal, dominated by the jet emission, and in some cases extends up to the very high energy gamma rays (VHE; E > 100 GeV. To date, more than 60 blazars have been detected at VHE mainly with ground-based imaging atmospheric Cherenkov telescopes (IACTs such as MAGIC, H.E.S.S., and VERITAS. Energetic photons from a blazar may interact with the diffuse optical and IR background (the extragalactic background light, EBL leaving an imprint on the blazar energy spectrum. This effect can be used to constrain the EBL, with basic assumptions on the intrinsic energy spectrum. Current generation of IACTs is providing valuable measurements of the EBL density and energy spectrum from optical to infrared frequencies. In this contribution, we present the latest results obtained with the data taken with the MAGIC telescopes: using 32 spectra from 12 blazars, the scale factor of the optical density predicted by the EBL model from Domínguez et al. (2011 is constrained to be 0.95 (+0.11, −0.12stat (+0.16, −0.07sys, where a value of 1 means the perfect match with the model.

  4. Neptune’s zonal winds from near-IR Keck adaptive optics imaging in August 2001

    NARCIS (Netherlands)

    Martin, S.C.; De Pater, I.; Marcus, P.

    2011-01-01

    We present H-band (1.4–1.8 ?m) images of Neptune with a spatial resolution of ?0.06?, taken with the W.M. Keck II telescope using the slit-viewing camera (SCAM) of the NIRSPEC instrument backed with Adaptive Optics. Images with 60-second integration times span 4 hours each on UT 20 and 21 August,

  5. An Inexpensive High Pressure Optical Absorption Cell for IR-VIS-UV Studies.

    Science.gov (United States)

    Rodgers, V. E.; Angell, C. A.

    1983-01-01

    Describes an optical cell, suitable for high-pressure studies between at least -130 and +150 degrees Celsius, which may be assembled for about $50. Discusses experimental demonstration of principles involved when using the apparatus, including effects of pressure on coordination of ions in solution and on reaction rates in solution. (JN)

  6. Development of IR single mode optical fibers for DARWIN-nulling interferometry

    NARCIS (Netherlands)

    Chakkalakkal Abdulla, S.M.; Cheng, L.K.; Bosch, B. van den; Dijkhuizen, N.; Nieuwland, R.A.; Gielesen, W.L.M.; Lucas, J.; Boussard-Plédel, C.; Conseil, C.; Bureau, B.; Carmo, J.P. do

    2014-01-01

    The DARWIN mission aims to detect weak infra-red emission lines from distant orbiting earth-like planets using nulling interferometry. This requires filtering of wavefront errors using single mode waveguides operating at a wavelength range of 6.5-20 μm. This article describes the optical design of

  7. Mid-IR optical properties of silicon doped InP

    DEFF Research Database (Denmark)

    Panah, Mohammad Esmail Aryaee; Han, Li; Norrman, Kion

    2017-01-01

    of growth conditions on the optical and electrical properties of silicon doped InP (InP:Si) in the wavelength range from 3 to 40 μm was studied. The carrier concentration of up to 3.9 × 1019 cm-3 is achieved by optimizing the growth conditions. The dielectric function, effective mass of electrons and plasma...

  8. Atomic and molecular spectroscopy with optical-frequency-comb-referenced IR coherent sources

    International Nuclear Information System (INIS)

    Cancio, P.; Bartalini, S.; De Rosa, M.; Giusfredi, G.; Mazzotti, D.; Maddaloni, P.; Vitiello, M. S.; De Natale, P.

    2013-01-01

    We provide a review of progress in the development of metrological-grade measurements in atomic and molecular systems through the extension, in the mid-infrared and far-infrared range, of optical frequency combs (OFCs) and the introduction of new techniques and highly coherent sources. (authors)

  9. Optimized geometry, vibration (IR and Raman spectra and nonlinear optical activity of p-nitroanilinium perchlorate molecule: A theoretical study

    Directory of Open Access Journals (Sweden)

    Tamer Ömer

    2016-03-01

    Full Text Available The molecular modeling of p-nitroanilinium perchlorate molecule was carried out by using B3LYP and HSEH1PBE levels of density functional theory (DFT. The IR and Raman spectra were simulated and the assignments of vibrational modes were performed on the basis of relative contribution of various internal co-ordinates. NBO analysis was performed to demonstrate charge transfer, conjugative interactions and the formation of intramolecular hydrogen bonding interactions within PNAPC. Obtained large dipole moment values showed that PNAPC is a highly polarizable complex, and the charge transfer occurs within PNAPC. Hydrogen bonding and charge transfer interactions were also displayed by small HOMO-LUMO gap and molecular electrostatic potential (MEP surface. The strong evidences that the material can be used as an efficient nonlinear optical (NLO material of PNAPC were demonstrated by considerable polarizability and hyperpolarizability values obtained at DFT levels.

  10. Multimode analysis of highly tunable, quantum cascade powered, circular graphene spaser

    Energy Technology Data Exchange (ETDEWEB)

    Jayasekara, Charith, E-mail: charith.jayasekara@monash.edu; Premaratne, Malin [Advanced Computing and Simulation Laboratory (A chi L), Department of Electrical and Computer Systems Engineering, Monash University, Clayton, Victoria 3800 (Australia); Stockman, Mark I. [Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (United States); Gunapala, Sarath D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

    2015-11-07

    We carried out a detailed analysis of a circular graphene spaser made of a circular graphene flake and a quantum cascade well structure. Owing to unique properties of graphene and quantum cascade well structure, the proposed design shows high mechanical and thermal stability and low optical losses. Additionally, operation characteristics of the model are analysed and tunability of the device is demonstrated. Some advantages of the proposed design include compact size, lower power operation, and the ability to set the operating wavelength over a wide range from Mid-IR to Near-IR. Thus, it can have wide spread applications including designing of ultracompact and ultrafast devices, nanoscopy and biomedical applications.

  11. J-Specific Dynamics in AN Optical Centrifuge Using Transient IR Spectroscopy

    Science.gov (United States)

    Murray, Matthew J.; Liu, Qingnan; Toro, Carlos; Mullin, Amy S.

    2013-06-01

    Quantum state-specific dynamics are reported for a number of CO_{2} rotational states in an optical centrifuge. The optical centrifuge results from combining oppositely-chirped ultrafast laser pulses and spinning CO_{2} molecules into extremely high rotational states with J≈220. Collisions of centrifuged molecules induce depletion of population from low-J states (J=0 and 36) and lead to appearance of population in high J states (J=36, 54 and 76). Transient Doppler-broadened line profiles for individual CO_{2} states reveal that the depletion populations have narrow velocity distributions with translational temperatures significantly colder than 300 K. Molecules that appear in the higher rotational states have broad velocity distributions, showing that both rotational and translational energy are imparted in collisions of the centrifuged molecules. These results show that substantial amounts of angular momentum persist after many collisions and that translational energy exchange continues for several thousand collisions.

  12. Highly stable ultrabroadband mid-IR optical parametric chirped-pulse amplifier optimized for superfluorescence suppression.

    Science.gov (United States)

    Moses, J; Huang, S-W; Hong, K-H; Mücke, O D; Falcão-Filho, E L; Benedick, A; Ilday, F O; Dergachev, A; Bolger, J A; Eggleton, B J; Kärtner, F X

    2009-06-01

    We present a 9 GW peak power, three-cycle, 2.2 microm optical parametric chirped-pulse amplification source with 1.5% rms energy and 150 mrad carrier envelope phase fluctuations. These characteristics, in addition to excellent beam, wavefront, and pulse quality, make the source suitable for long-wavelength-driven high-harmonic generation. High stability is achieved by careful optimization of superfluorescence suppression, enabling energy scaling.

  13. Ultrafast Mid-IR Nonlinear Optics in Gas-filled Hollow-core Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Habib, Selim

    Invention of hollow-core fiber has been proven an ideal medium to study light-gas interaction. Tight confinement of light inside hollowcore fiber allows unremitting and tailored interaction between light and gas over long distances. In this work, we used a special kind of hollowcore fiber − hollow......-core anti-resonant (HC-AR) fiber to study the various nonlinear effects filled with Raman free noble gas. One of the main striking features of HC-AR fiber is that ∼99.99% light can be guided inside the central hollow-core region, which significantly enhances damage threshold level. HC-AR fiber can sustain...... be tuned by simply changing the pressure of the gas while at the same time providing extremely wide transparency ranges. In this thesis, we propose several low-loss broadband guidance HC-AR fibers and investigate soliton-plasma dynamics using HC-AR fiber filled with noble gas in the mid-IR. The combined...

  14. New autocorrelation technique for the IR FEL optical pulse width measurements

    Energy Technology Data Exchange (ETDEWEB)

    Amirmadhi, F.; Brau, K.A.; Becker, C. [Vanderbilt Univ., Nashville, TN (United States)] [and others

    1995-12-31

    We have developed a new technique for the autocorrelation measurement of optical pulse width at the Vanderbilt University FEL center. This method is based on nonlinear absorption and transmission characteristics of semiconductors such as Ge, Te and InAs suitable for the wavelength range from 2 to over 6 microns. This approach, aside being simple and low cost, removes the phase matching condition that is generally required for the standard frequency doubling technique and covers a greater wavelength range per nonlinear material. In this paper we will describe the apparatus, explain the principal mechanism involved and compare data which have been acquired with both frequency doubling and two-photon absorption.

  15. Precision Determination of Atmospheric Extinction at Optical and Near IR Wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Burke, David L.; /SLAC; Axelrod, T.; /Arizona U., Astron. Dept. - Steward Observ.; Blondin, Stephane; /European Southern Observ. /Marseille, CPPM; Claver, Chuck; /NOAO, Tucson; Ivezic, Zeljko; Jones, Lynne; /Washington U., Seattle, Astron. Dept.; Saha, Abhijit; /NOAO, Tucson; Smith, Allyn; /Austin Peay State U.; Smith, R.Chris; /Cerro-Tololo InterAmerican Obs.; Stubbs, Christopher W.; /Harvard-Smithsonian Ctr. Astrophys.

    2011-08-24

    The science goals for future ground-based all-sky surveys, such as the Dark Energy Survey, PanSTARRS, and the Large Synoptic Survey Telescope, require calibration of broadband photometry that is stable in time and uniform over the sky to precisions of a per cent or better, and absolute calibration of color measurements that are similarly accurate. This performance will need to be achieved with measurements made from multiple images taken over the course of many years, and these surveys will observe in less than ideal conditions. This paper describes a technique to implement a new strategy to directly measure variations of atmospheric transmittance at optical wavelengths and application of these measurements to calibration of ground-based observations. This strategy makes use of measurements of the spectra of a small catalog of bright 'probe' stars as they progress across the sky and back-light the atmosphere. The signatures of optical absorption by different atmospheric constituents are recognized in these spectra by their characteristic dependences on wavelength and airmass. State-of-the-art models of atmospheric radiation transport and modern codes are used to accurately compute atmospheric extinction over a wide range of observing conditions. We present results of an observing campaign that demonstrate that correction for extinction due to molecular constituents and aerosols can be done with precisions of a few millimagnitudes with this technique.

  16. 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.

  17. Optical Remote Sensing for Fence-Line Monitoring using Open-Path Quantum Cascade Laser (QCL) mono-static system for multiple target compounds in the Mid IR 7-13um (Fingerprint) region.

    Science.gov (United States)

    Zemek, P. G.

    2017-12-01

    Quantum Cascade Lasers (QCLs) are quickly replacing Tunable Diode Lasers (TDL) for multi-target species identification and quantification in both extractive and open-path (OP) Optical Remote Sensing (ORS) fence-line instrumentation. As was seen with TDL incorporation and pricing drops as the adoption by the telecommunications industry and its current scaling has improved robustness and pricing, the QCL is also, albiet more slowly, becoming a mature market. There are several advantages of QCLs over conventional TDLs such as improved brightness and beam density, high resolution, as well as the incorporation of external etalons or internal gratings to scan over wide spectral areas. QCLs typically operate in the Mid infra-red (MIR) as opposed to the Near-Infrared (NIR) region used with TDL. The MidIR is a target rich absorption band area where compounds have high absorbtivity coefficients resulting in better detection limits as compared to TDL instruments. The use of novel chemometrics and more sensitive non-cryo-cooled detectors has allowed some of the first QCL open-path instruments in both active and passive operation. Data and field studies of one of the newest QCL OP systems is presented that allows one system to measure multiple target compounds. Multiple QCL spectral regions may be stitched together to increase the capability of QCLs over TDL OP systems. A comparison of several ORS type systems will be presented.

  18. Optical Cherenkov radiation by cascaded nonlinear interaction: an efficient source of few-cycle energetic near- to mid-IR pulses

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Zhou, Binbin

    2011-01-01

    When ultrafast noncritical cascaded second-harmonic generation of energetic femtosecond pulses occur in a bulk lithium niobate crystal optical Cherenkov waves are formed in the near- to mid-IR. Numerical simulations show that the few-cycle solitons radiate Cherenkov (dispersive) waves in the λ = 2...

  19. Tunable, multiwavelength-swept fiber laser based on nematic liquid crystal device for fiber-optic electric-field sensor

    Science.gov (United States)

    Lee, Hyun Ji; Kim, Sung-Jo; Ko, Myeong Ock; Kim, Jong-Hyun; Jeon, Min Yong

    2018-03-01

    We propose a tunable multiwavelength-swept laser based on a nematic liquid crystal (NLC) Fabry-Perot (FP) etalon, which is embedded in the resonator of a wavelength-swept laser. We achieve the continuous wavelength tuning of the multiwavelength-swept laser by applying the electric field to the NLC FP etalon. The free spectral range of the fabricated NLC FP etalon is approximately 7.9 nm. When the electric field applied to the NLC FP etalon exceeds the threshold value (Fréedericksz threshold voltage), the output of the multiwavelength-swept laser can be tuned continuously. The tuning range of the multiwavelength-swept laser can be achieved at a value greater than 75 nm, which has a considerably wider tunable range than a conventional multiwavelength laser based on an NLC FP etalon. The slope efficiencies in the spectral and temporal domains for the tunable multiwavelength-swept laser are 22.2 nm/(mVrms / μm) and 0.17 ms/(mVrms / μm), respectively in the linear region. Therefore, the developed multiwavelength-swept laser based on the NLC FP etalon can be applied to an electric-field sensor. Because the wavelength measurement and time measurement have a linear relationship, the electric-field sensor can detect a rapid change in the electric-field intensity by measuring the peak change of the pulse in the temporal domain using the NLC FP etalon-based multiwavelength-swept laser.

  20. The influence of optical parameters on impurity determinations by IR spectroscopy

    International Nuclear Information System (INIS)

    Lombard, O.J.

    1985-01-01

    The important role of impurities in semiconductor materials is the subject of continuous research. The concentration of interstitial oxygen impurities in silicon are determined with the aid of infrared spectroscopy. The maximum absorption coefficient of the oxygen absorption peak, centered at 9,06 μm, is determined and the impurity concentration is then calculated using a calibration factor. This procedure was evaluated, paying particular attention to those optical parameters which may influence these impurity determinations. A thorough discussion of the theoretical and experimental aspects of infrared spectroscopy in general is followed by an overview of previous experimental work. This lead to some theoretical analysis regarding the influence of the index of refraction, the index of absorption and multiple reflections in the silicon wafer on impurity determinations. This lead to specific experimental investigations. The influence of the surface morphology of samples on impurity determinations was studied by determining the reflectance of silicon surfaces. It was established that the surface reflectance plays a role and that it must be taken into consideration for accurate impurity concentration determinations. The most accurate values for the absorption coefficient due to oxygen in silicon are calculated. This requires that the surface of the silicon wafers must be highly polished for the formula to be valid. Acceptable values for the absorption coefficient of damaged surfaces are obtained if the uncorrected formula is used. Experimental results may deviate as much as 32% from the real impurity concentration if the wrong formula is used to calculate the absorption coefficient of oxygen in silicon at 9,06 μm

  1. Tunable, high-repetition-rate, dual-signal-wavelength femtosecond optical parametric oscillator based on BiB3O6

    Science.gov (United States)

    Meng, Xianghao; Wang, Zhaohua; Tian, Wenlong; Fang, Shaobo; Wei, Zhiyi

    2018-01-01

    We have demonstrated a high-repetition-rate tunable femtosecond dual-signal-wavelength optical parametric oscillator (OPO) based on BiB3O6 (BiBO) crystal, synchronously pumped by a frequency-doubled mode-locked Yb:KGW laser. The cavity is simple since no dispersion compensators are used in the cavity. The wavelength range of dual-signal is widely tunable from 710 to 1000 nm. Tuning is accomplished by rotating phase-matching angle of BiBO, and optimizing cavity length and output coupler. Using a 3.75 W pump laser, the maximum average dual-signal output power is 760 mW at 707 and 750 nm, leading to a conversion efficiency of 20.3% not taking into account the idler power. Our experimental results show a non-critical phase-matching configuration pumped by a high peak power laser source. The operation of the dual-signal benefits from the balance of phase matching and group velocity mismatching between the two signals.

  2. Comparison of Fiber Optic and Conduit Attenuated Total Reflection (ATR) Fourier Transform Infrared (FT-IR) Setup for In-Line Fermentation Monitoring.

    Science.gov (United States)

    Koch, Cosima; Posch, Andreas E; Herwig, Christoph; Lendl, Bernhard

    2016-12-01

    The performance of a fiber optic and an optical conduit in-line attenuated total reflection mid-infrared (IR) probe during in situ monitoring of Penicillium chrysogenum fermentation were compared. The fiber optic probe was connected to a sealed, portable, Fourier transform infrared (FT-IR) process spectrometer via a plug-and-play interface. The optical conduit, on the other hand, was connected to a FT-IR process spectrometer via a knuckled probe with mirrors that had to be adjusted prior to each fermentation, which were purged with dry air. Penicillin V (PenV) and its precursor phenoxyacetic acid (POX) concentrations were determined by online high-performance liquid chromatography and the obtained concentrations were used as reference to build partial least squares regression models. Cross-validated root-mean-square errors of prediction were found to be 0.2 g L -1 (POX) and 0.19 g L -1 (PenV) for the fiber optic setup and 0.17 g L -1 (both POX and PenV) for the conduit setup. Higher noise-levels and spectrum-to-spectrum variations of the fiber optic setup lead to higher noise of estimated (i.e., unknown) POX and PenV concentrations than was found for the conduit setup. It seems that trade-off has to be made between ease of handling (fiber optic setup) and measurement accuracy (optical conduit setup) when choosing one of these systems for bioprocess monitoring. © The Author(s) 2016.

  3. VARIABILITY AT THE EDGE: OPTICAL NEAR/IR RAPID-CADENCE MONITORING OF NEWLY OUTBURSTING FU ORIONIS OBJECT HBC 722

    International Nuclear Information System (INIS)

    Green, Joel D.; Robertson, Paul; Pak, Soojong; Meschiari, Stefano; Baek, Giseon; Lee, Jeong-Eun; Pooley, David; Im, Myungshin; Jeon, Yiseul; Choi, Changsu

    2013-01-01

    We present the detection of day-timescale periodic variability in the r-band lightcurve of newly outbursting FU Orionis-type object HBC 722, taken from >42 nights of observation with the CQUEAN instrument on the McDonald Observatory 2.1 m telescope. The optical/near-IR lightcurve of HBC 722 shows a complex array of periodic variability, clustering around 5.8-day (0.044 mag amplitude) and 1.28-day (0.016 mag amplitude) periods, after removal of overall baseline variation. We attribute the unusual number of comparable strength signals to a phenomenon related to the temporary increase in accretion rate associated with FUors. We consider semi-random 'flickering', magnetic braking/field compression and rotational asymmetries in the disk instability region as potential sources of variability. Assuming that the 5.8-day period is due to stellar rotation and the 1.28-day period is indicative of Keplerian rotation at the inner radius of the accretion disk (at 2 R * ), we derive a B-field strength of 2.2-2.7 kG, slightly larger than typical T Tauri stars. If instead the 5.8-day signal is from a disk asymmetry, the instability region has an outer radius of 5.4 R * , consistent with models of FUor disks. Further exploration of the time domain in this complicated source and related objects will be key to understanding accretion processes.

  4. Polarization-independent rapidly tunable optical add-drop multiplexer utilizing non-polarizing beam splitters in Ti:LiNbO3

    Science.gov (United States)

    Shin, Yong-Wook; Sung, Won Ju; Eknoyan, O.; Madsen, C. K.; Taylor, H. F.

    2012-04-01

    A polarization-independent four-port wavelength-tunable optical add drop multiplexer (OADM) that utilizes non-polarizing relaxed beam splitters has been analyzed and demonstrated in Ti:LiNbO3 at the 1530 nm wavelength regime. The design utilizes an asymmetric interferometer configuration with strain induced index grating for polarization coupling along its arms that are shifted in position relative to each other. Experimental results of the filter response agree with theoretical predictions. Electrooptic tuning over a range of 15.7 nm at a rate of 0.08 nm/V has been measured. A temporal response < 46 ns to a 20 V step change in tuning voltage has been demonstrated. Fiber-to-fiber insertion loss is ~ 6.5 dB.

  5. Optical properties of reduced graphene oxide and CuFe2O4 composites in the IR region

    Science.gov (United States)

    Ma, De-yue; Li, Xiao-xia; Guo, Yu-xiang; Zeng, Yu-run

    2018-01-01

    The complex refractive index of reduced graphene oxide and CuFe2O4 composites prepared by hydrothermal method was calculated using infrared Micro-reflective spectra and K-K relation, and the calculation errors were analyzed according to its IR transmission and spectral reflectivity calculated by Fresnel formula. And then normal emissivity of the composite in IR atmospheric window was calculated by means of Fresnel formula and modified refraction angle formula. The calculation accuracy was verified by comparing measured normal total emissivity with the calculated one. The results show that complex refractive index and normal emissivity calculated by the formulas have a high accuracy. It has been found that the composite has a good absorption and radiation characteristics in IR atmospheric window and a strong scattering ability in middle IR region by analyzing its extinction, absorption and radiation properties in IR region. Therefore, it may be used as IR absorption, extinction and radiation materials in some special fields.

  6. Long range surface plasmon resonance enhanced electro-optically tunable Goos-Hänchen shift and Imbert-Fedorov shift in ZnSe prism

    Science.gov (United States)

    Goswami, Nabamita; Kar, Aparupa; Saha, Ardhendu

    2014-11-01

    A new theoretical approach towards the tuning of Goos-Hänchen shift and Imbert-Fedorov shift for the reflected light beam is observed, designed and simulated in this paper through electro-optically tunable liquid crystal at an incident wavelength of 1550 nm within the communication window. Here the considered Kretschmann-Raether geometry comprises a ZnSe prism and a liquid crystal layer of E44 between two metal layers of silver, where with the application of electric field from (0-10) V electro-optically tuning of the Goos-Hänchen shift from 64.09 μm to -53.408 μm and the Imbert-Fedorov shift from 122.8 μm to -32.5 μm for a change in refractive index of the liquid crystal layer from 1.52-1.79 are envisaged. This idea expedites the scope of fine tuning in optical switching within the μm ranges.

  7. The visible to the near infrared narrow band acousto-optic tunable filter and the hyperspectral microscopic imaging on biomedicine study

    International Nuclear Information System (INIS)

    Zhang, Chunguang; Wang, Hao; Huang, Junfeng; Gao, Qiang

    2014-01-01

    Based on the parallel tangents momentum-matching condition, a narrow band noncollinear acousto-optic tunable filter (AOTF) using a single TeO 2 crystal is designed with the consideration of the birefringence and the rotatory property of the material. An effective setup is established to evaluate the performance of the designed AOTF. The experimental observed spectrum pattern of the diffracted light is nearly the same with the theoretical result. The measured tuning relationship between the diffracted central optical wavelength and acoustic frequency is in accordance with the theoretical prospect. The optical bandwidth of the diffracted light is as narrow as 1.88 nm when the central wavelength is 556.75 nm. The high spectral resolution is significant in practical applications of imaging AOTF. Additionally, the AOTF based hyperspectral microscopic imaging system is established. The stability and the image resolution of the designed narrow band AOTF are satisfying. Finally, the study of the biologic samples indicates the feasibility of our system on biomedicine. (paper)

  8. 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.

  9. An optical-near-IR study of a triplet of super star clusters in the starburst core of M82

    Energy Technology Data Exchange (ETDEWEB)

    Westmoquette, M. S. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany); Bastian, N. [Excellence Cluster Universe, Boltzmannstrasse 2, D-85748 Garching bei München (Germany); Smith, L. J. [Space Telescope Science Institute and European Space Agency, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Seth, A. C. [University of Utah, Salt Lake City, UT 84112 (United States); Gallagher III, J. S.; Ryon, J. E. [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling, 475 North Charter Street, Madison, WI 53706 (United States); O' Connell, R. W. [Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903 (United States); Silich, S.; Mayya, Y. D.; González, D. Rosa [Instituto Nacional de Astrofísica, Optica y Electronica, Luis Enrique Erro 1, Tonantzintla, C.P. 72840, Puebla (Mexico); Muñoz-Tuñón, C., E-mail: westmoquette@gmail.com [Instituto de Astrofísica de Canarias, C/vía Láctea s/n, E-38200 La Laguna, Tenerife (Spain)

    2014-07-10

    We present HST/STIS optical and Gemini/NIFS near-IR IFU spectroscopy and archival Hubble Space Telescope (HST) imaging of the triplet of super star clusters (A1, A2, and A3) in the core of the M82 starburst. Using model fits to the Space Telescope Imaging Spectrograph (STIS) spectra and the weakness of red supergiant CO absorption features (appearing at ∼6 Myr) in the NIFS H-band spectra, the ages of A2 and A3 are 4.5 ± 1.0 Myr. A1 has strong CO bands, consistent with our previously determined age of 6.4 ± 0.5 Myr. The photometric masses of the three clusters are 4-7 × 10{sup 5} M{sub ☉}, and their sizes are R{sub eff} = 159, 104, 59 mas (∼2.8, 1.8, 1.0 pc) for A1, A2, and A3. The STIS spectra yielded radial velocities of 320 ± 2, 330 ± 6, and 336 ± 5 km s{sup –1} for A1, A2, and A3, placing them at the eastern end of the x{sub 2} orbits of M82's bar. Clusters A2 and A3 are in high-density (800-1000 cm{sup –3}) environments, and like A1, are surrounded by compact H II regions. We suggest the winds from A2 and A3 have stalled, as in A1, due to the high ISM ambient pressure. We propose that the three clusters were formed in situ on the outer x{sub 2} orbits in regions of dense molecular gas subsequently ionized by the rapidly evolving starburst. The similar radial velocities of the three clusters and their small projected separation of ∼25 pc suggest that they may merge in the near future unless this is prevented by velocity shearing.

  10. Fiber optic lasers with emission to the region 2-3 μm of IR medium

    International Nuclear Information System (INIS)

    Anzuelo Sanchez, G.; Osuna Galan, I.; Camas Anzueto, J.; Martinez Rios, A.; Selvas Aguilar, R.

    2009-01-01

    We present recent advances in laser emission in the 2-2-5 μm mid-IR, using a chalcogenide fiber with low loss and a high Raman gain in the region 2-10 μm. We present a review of fiber lasers operating in 2-3 μm of the mid IR. (Author)

  11. A next generation Ultra-Fast Flash Observatory (UFFO-100) for IR/optical observations of the rise phase of gamma-ray bursts

    DEFF Research Database (Denmark)

    Grossan, B.; Park, I.H.; Ahmad, S.

    2012-01-01

    generation of rapid-response space observatory instruments. We list science topics motivating ourinstruments, those that require rapid optical-IR GRB response, including: A survey of GRB rise shapes/times,measurements of optical bulk Lorentz factors, investigation of magnetic dominated (vs. non-magnetic) jet...... for a next generation space observatory as a secondinstrument on a low-earth orbit spacecraft, with a 120 kg instrument mass budget. Restricted to relatively modest mass,power, and launch resources, we find that a coded mask X-ray camera with 1024 cm2 of detector area could rapidlylocate about 64...

  12. Fabrication of Au/graphene oxide/Ag sandwich structure thin film and its tunable energetics and tailorable optical properties

    OpenAIRE

    Ruijin Hong; Jialin Ji; Chunxian Tao; Daohua Zhang; Dawei Zhang

    2017-01-01

    Au/graphene oxide/Ag sandwich structure thin film was fabricated. The effects of graphene oxide (GO) and bimetal on the structure and optical properties of metal silver films were investigated by X-ray diffraction (XRD), optical absorption, and Raman intensity measurements, respectively. Compared to silver thin film, Au/graphene oxide/Ag sandwich structure composite thin films were observed with wider optical absorption peak and enhanced absorption intensity. The Raman signal for Rhodamine B ...

  13. Mid-IR laser system for advanced neurosurgery

    Science.gov (United States)

    Klosner, M.; Wu, C.; Heller, D. F.

    2014-03-01

    We present work on a laser system operating in the near- and mid-IR spectral regions, having output characteristics designed to be optimal for cutting various tissue types. We provide a brief overview of laser-tissue interactions and the importance of controlling certain properties of the light beam. We describe the principle of operation of the laser system, which is generally based on a wavelength-tunable alexandrite laser oscillator/amplifier, and multiple Raman conversion stages. This configuration provides robust access to the mid-IR spectral region at wavelengths, pulse energies, pulse durations, and repetition rates that are attractive for neurosurgical applications. We summarize results for ultra-precise selective cutting of nerve sheaths and retinas with little collateral damage; this has applications in procedures such as optic-nerve-sheath fenestration and possible spinal repair. We also report results for cutting cornea, and dermal tissues.

  14. Large depth of focus dynamic micro integral imaging for optical see-through augmented reality display using a focus-tunable lens.

    Science.gov (United States)

    Shen, Xin; Javidi, Bahram

    2018-03-01

    We have developed a three-dimensional (3D) dynamic integral-imaging (InIm)-system-based optical see-through augmented reality display with enhanced depth range of a 3D augmented image. A focus-tunable lens is adopted in the 3D display unit to relay the elemental images with various positions to the micro lens array. Based on resolution priority integral imaging, multiple lenslet image planes are generated to enhance the depth range of the 3D image. The depth range is further increased by utilizing both the real and virtual 3D imaging fields. The 3D reconstructed image and the real-world scene are overlaid using an optical see-through display for augmented reality. The proposed system can significantly enhance the depth range of a 3D reconstructed image with high image quality in the micro InIm unit. This approach provides enhanced functionality for augmented information and adjusts the vergence-accommodation conflict of a traditional augmented reality display.

  15. Tunable dye laser research at U. N. E

    Energy Technology Data Exchange (ETDEWEB)

    Haydon, S C

    1976-10-01

    Attempts to extend present tunable radiation sources into the wavelength region from 140 to 330 nm are presented in the following areas: frequency doubling and parametric upconversion methods, frequency mixing techniques in metal vapors, the pulsed N/sub 2/ laser, tunable dye lasers for the near uv to ir spectral range, heat pipe ovens, and preliminary experiments. (MHR)

  16. Tunable Beam Diffraction in Infiltrated Microstructured Fibers

    DEFF Research Database (Denmark)

    Rosberg, Christian Romer; Bennet, Francis H.; Neshev, Dragomir N.

    We experimentally study beam propagation in two dimensional photonic lattices in microstructured optical fibers infiltrated with high index liquids. We demonstrate strongly tunable beam diffraction by dynamically varying the coupling between individual lattice sites.......We experimentally study beam propagation in two dimensional photonic lattices in microstructured optical fibers infiltrated with high index liquids. We demonstrate strongly tunable beam diffraction by dynamically varying the coupling between individual lattice sites....

  17. Tunable on chip optofluidic laser

    DEFF Research Database (Denmark)

    Bakal, Avraham; Vannahme, Christoph; Kristensen, Anders

    2015-01-01

    A chip scale tunable laser in the visible spectral band is realized by generating a periodic droplet array inside a microfluidic channel. Combined with a gain medium within the droplets, the periodic structure provides the optical feedback of the laser. By controlling the pressure applied to two...

  18. Demonstration of tunable microwave photonic notch filters using slow and fast light effects in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Xue, Weiqi; Sales, Salvador; Mørk, Jesper

    2009-01-01

    We introduce a novel scheme based on slow and fast light effects in semiconductor optical amplifiers, to implement a microwave photonic notch filter with ~100% fractional tuning range at a microwave frequency of 30 GHz....

  19. Constraining the Volatile Composition and Coma Photochemistry in Jupiter Family Comet 41P/Tuttle-Giacobini-Kresak with High Resolution IR and Optical Spectroscopy

    Science.gov (United States)

    McKay, Adam; DiSanti, Michael; Cochran, Anita; Dello Russo, Neil; Bonev, Boncho; Vervack, Ronald; Gibb, Erika; Roth, Nathan; Kawakita, Hideyo

    2018-01-01

    Over the past 20 years optical and IR spectroscopy of cometary comae has expanded our understanding both of cometary volatile composition and coma photochemistry. However, these observations tend to be biased towards Nearly Isotropic Comets (NIC'S) from the Oort Cloud, rather than the generally fainter and less active Jupiter Family Comets (JFC's) that are thought to originate from the Scattered Disk. However, early 2017 provided a rare opportunity to study several JFC's. We present preliminary results from IR and optical spectroscopy of JFC 41P/Tuttle-Giacobini-Kresak obtained during its 2017 apparition. IR spectra were obtained with the NIRSPEC instrument on Keck II and the new iSHELL spectrograph on NASA IRTF. High spectral resolution optical spectra were obtained with the Tull Coude spectrograph on the 2.7-meter Harlan J. Smith Telescope at McDonald Observatory. We will discuss mixing ratios of HCN, NH3, C2H6, C2H2, H2CO, and CH3OH compared to H2O and compare these to previous observations of comets. Preliminary results from the NIRSPEC observations indicate that 41P has typical C2H2 and HCN abundances compared to other JFC's, while the C2H6 abundance is similar to that of NIC's, but is enriched compared to other JFC's. H2CO appears to be heavily depleted in 41P. Analysis of the iSHELL spectra is underway and we will include results from these observations, which complement those from NIRSPEC and extend the scope or our compositional study by measuring additional molecules. We will also present abundances for CN, C2, NH2, C3, and CH obtained from the optical spectra and discuss the implications for the coma photochemistry.This work is supported by the NASA Postdoctoral Program, administered by the Universities Space Research Association, with additional funding from the NSF and NASA PAST.

  20. Tunable erbium-doped fiber laser based on optical fiber Sagnac interference loop with angle shift spliced polarization maintaining fibers

    Science.gov (United States)

    Ding, Zhenming; Wang, Zhaokun; Zhao, Chunliu; Wang, Dongning

    2018-05-01

    In this paper, we propose and experimentally demonstrate a tunable erbium-doped fiber laser (EDFL) with Sagnac interference loop with 45° angle shift spliced polarization maintaining fibers (PMFs). In the Sagnac loop, two PMFs with similar lengths. The Sagnac loop outputs a relatively complex interference spectrum since two beams transmitted in clockwise and counterclockwise encounter at the 3 dB coupler, interfere, and form two interference combs when the light transmitted in the Sagnac loop. The laser will excite and be stable when two interference lines in these two interference combs overlap together. Then by adjusting the polarization controller, the wide wavelength tuning is realized. Experimental results show that stable single wavelength laser can be realized in the wavelength range of 1585 nm-1604 nm under the pump power 157.1 mW. The side-mode suppression ratio is not less than 53.9 dB. The peak power fluctuation is less than 0.29 dB within 30 min monitor time and the side-mode suppression ratio is great than 57.49 dB when the pump power is to 222.7 mW.

  1. Generation of high-energy sub-20 fs pulses tunable in the 250-310 nm region by frequency doubling of a high-power noncollinear optical parametric amplifier.

    Science.gov (United States)

    Beutler, Marcus; Ghotbi, Masood; Noack, Frank; Brida, Daniele; Manzoni, Cristian; Cerullo, Giulio

    2009-03-15

    We report on the generation of powerful sub-20 fs deep UV pulses with 10 microJ level energy and broadly tunable in the 250-310 nm range. These pulses are produced by frequency doubling a high-power noncollinear optical parametric amplifier and compressed by a pair of MgF2 prisms to an almost transform-limited duration. Our results provide a power scaling by an order of magnitude with respect to previous works.

  2. VCSEL-based gigabit IR-UWB link for converged communication and sensing applications in optical metro-access networks

    DEFF Research Database (Denmark)

    Pham, Tien Thang; Gibbon, Timothy Braidwood; Tafur Monroy, Idelfonso

    2012-01-01

    We report on experimental demonstration of an impulse radio ultrawideband (IR-UWB) based converged communication and sensing system. A 1550-nm VCSEL-generated IR-UWB signal is used for 2-Gbps wireless data distribution over 800-m and 50-km single mode fiber links which present short-range in-buil...... application, paving the way forward for the development and deployment of converged UWB VCSEL-based technologies in access and in-building networks of the future.......We report on experimental demonstration of an impulse radio ultrawideband (IR-UWB) based converged communication and sensing system. A 1550-nm VCSEL-generated IR-UWB signal is used for 2-Gbps wireless data distribution over 800-m and 50-km single mode fiber links which present short-range in......-building and long-reach access network applications. The IR-UWB signal is also used to simultaneously measure the rotational speed of a blade spinning between 18 and 30 Hz. To the best of our knowledge, this is the very first demonstration of a simultaneous gigabit UWB telecommunication and wireless UWB sensing...

  3. pH-Induced Surface Modification of Atomically Precise Silver Nanoclusters: An Approach for Tunable Optical and Electronic Properties

    KAUST Repository

    AbdulHalim, Lina G.

    2016-10-24

    Noble metal nanoclusters (NCs) play a pivotal role in bridging the gap between molecules and quantum dots. Fundamental understanding of the evolution of the structural, optical, and electronic properties of these materials in various environments is of paramount importance for many applications. Using state-of-the-art spectroscopy, we provide the first decisive experimental evidence that the structural, electronic, and optical properties of Ag-44(MNBA)(30) NCs can now be tailored by controlling the chemical environment. Infrared and photoelectron spectroscopies clearly indicate that there is a dimerization between two adjacent ligands capping the NCs that takes place upon lowering the pH from 13 to 7.

  4. Additive manufacturing of tunable lenses

    Science.gov (United States)

    Schlichting, Katja; Novak, Tobias; Heinrich, Andreas

    2017-02-01

    Individual additive manufacturing of optical systems based on 3D Printing offers varied possibilities in design and usage. In addition to the additive manufacturing procedure, the usage of tunable lenses allows further advantages for intelligent optical systems. Our goal is to bring the advantages of additive manufacturing together with the huge potential of tunable lenses. We produced tunable lenses as a bundle without any further processing steps, like polishing. The lenses were designed and directly printed with a 3D Printer as a package. The design contains the membrane as an optical part as well as the mechanical parts of the lens, like the attachments for the sleeves which contain the oil. The dynamic optical lenses were filled with an oil. The focal length of the lenses changes due to a change of the radius of curvature. This change is caused by changing the pressure in the inside of the lens. In addition to that, we designed lenses with special structures to obtain different areas with an individual optical power. We want to discuss the huge potential of this technology for several applications. Further, an appropriate controlling system is needed. Wéll show the possibilities to control and regulate the optical power of the lenses. The lenses could be used for illumination tasks, and in the future, for individual measurement tasks. The main advantage is the individuality and the possibility to create an individual design which completely fulfills the requirements for any specific application.

  5. Widely tunable dispersive wave generation and soliton self-frequency shift in a tellurite microstructured optical fiber pumped near the zero dispersion wavelength

    International Nuclear Information System (INIS)

    Zhang, Lei; Tuan, Tong-Hoang; Liu, Lai; Gao, Wei-Qing; Kawamura, Harutaka; Suzuki, Takenobu; Ohishi, Yasutake

    2015-01-01

    Widely tunable dispersive waves (DW) and Raman solitons are generated in a tellurite microstructured optical fiber (TMOF) by pumping in the anomalous dispersion regime, close to the zero dispersion wavelength (ZDW). The DW can be generated from 1518.3 nm to 1315.5 nm, and the soliton can be shifted from the pump wavelength of 1570 nm to 1828.7 nm, by tuning the average pump power from 3 dBm to 17.5 dBm. After the average pump power is increased to 18.8 dBm, two DW peaks (centered at 1323 nm and 1260 nm) and three soliton peaks (centered at 1762 nm, 1825 nm, and 1896 nm) can be observed simultaneously. When the average pump power is greater than 23.4 dBm, a flat and broadband supercontinuum (SC) can be formed by the combined nonlinear effects of soliton self-frequency shift (SSFS), DW generation, and cross phase modulation (XPM). (paper)

  6. Diffractive centrosymmetric 3D-transmission phase gratings positioned at the image plane of optical systems transform lightlike 4D-WORLD as tunable resonators into spectral metrics...

    Science.gov (United States)

    Lauinger, Norbert

    1999-08-01

    Diffractive 3D phase gratings of spherical scatterers dense in hexagonal packing geometry represent adaptively tunable 4D-spatiotemporal filters with trichromatic resonance in visible spectrum. They are described in the (lambda) - chromatic and the reciprocal (nu) -aspects by reciprocal geometric translations of the lightlike Pythagoras theorem, and by the direction cosine for double cones. The most elementary resonance condition in the lightlike Pythagoras theorem is given by the transformation of the grating constants gx, gy, gz of the hexagonal 3D grating to (lambda) h1h2h3 equals (lambda) 111 with cos (alpha) equals 0.5. Through normalization of the chromaticity in the von Laue-interferences to (lambda) 111, the (nu) (lambda) equals (lambda) h1h2h3/(lambda) 111-factor of phase velocity becomes the crucial resonance factor, the 'regulating device' of the spatiotemporal interaction between 3D grating and light, space and time. In the reciprocal space equal/unequal weights and times in spectral metrics result at positions of interference maxima defined by hyperbolas and circles. A database becomes built up by optical interference for trichromatic image preprocessing, motion detection in vector space, multiple range data analysis, patchwide multiple correlations in the spatial frequency spectrum, etc.

  7. Real-time monitoring of benzene, toluene, and p-xylene in a photoreaction chamber with a tunable mid-infrared laser and ultraviolet differential optical absorption spectroscopy.

    Science.gov (United States)

    Parsons, Matthew T; Sydoryk, Ihor; Lim, Alan; McIntyre, Thomas J; Tulip, John; Jäger, Wolfgang; McDonald, Karen

    2011-02-01

    We describe the implementation of a mid-infrared laser-based trace gas sensor with a photoreaction chamber, used for reproducing chemical transformations of benzene, toluene, and p-xylene (BTX) gases that may occur in the atmosphere. The system performance was assessed in the presence of photoreaction products including aerosol particles. A mid-infrared external cavity quantum cascade laser (EC-QCL)-tunable from 9.41-9.88 μm (1012-1063 cm(-1))-was used to monitor gas phase concentrations of BTX simultaneously and in real time during chemical processing of these compounds with hydroxyl radicals in a photoreaction chamber. Results are compared to concurrent measurements using ultraviolet differential optical absorption spectroscopy (UV DOAS). The EC-QCL based system provides quantitation limits of approximately 200, 200, and 600 parts in 10(9) (ppb) for benzene, toluene, and p-xylene, respectively, which represents a significant improvement over our previous work with this laser system. Correspondingly, we observe the best agreement between the EC-QCL measurements and the UV DOAS measurements with benzene, followed by toluene, then p-xylene. Although BTX gas-detection limits are not as low for the EC-QCL system as for UV DOAS, an unidentified by-product of the photoreactions was observed with the EC-QCL, but not with the UV DOAS system.

  8. Tunability of Open-Shell Character, Charge Asymmetry, and Third-Order Nonlinear Optical Properties of Covalently Linked (Hetero)Phenalenyl Dimers.

    Science.gov (United States)

    Minamida, Yuka; Kishi, Ryohei; Fukuda, Kotaro; Matsui, Hiroshi; Takamuku, Shota; Yamane, Masaki; Tonami, Takayoshi; Nakano, Masayoshi

    2018-02-06

    Tunability of the open-shell character, charge asymmetry, and third-order nonlinear optical (NLO) properties of covalently linked (hetero)phenalenyl dimers are investigated by using the density functional theory method. By changing the molecular species X and substitution position (i, j) for the linker part, a variety of intermonomer distances R and relative alignments between the phenalenyl dimers can be realized from the geometry optimizations, resulting in a wide-range tuning of diradical character y and charge asymmetry. It is found that the static second hyperpolarizabilities along the stacking direction, γ yyyy , are one-order enhanced for phenalenyl dimer systems exhibiting intermediate y, a feature that is in good agreement with the "y-γ correlation". By replacing the central carbon atoms of the phenalenyl rings with a boron or a nitrogen, we have also designed covalently linked heterophenalenyl dimers. The introduction of such a charge asymmetry to the open-shell systems, which leads to closed-shell ionic ground states, is found to further enhance the γ yyyy values of the systems having longer intermonomer distance R with intermediate ionic character, that is, charge asymmetry. The present results demonstrate a promising potential of covalently linked NLO dimers with intermediate open-shell/ionic characters as a new building block of highly efficient NLO systems. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A facile synthesis of C{sub 60}-organosilicon hybrid polymers: Considering their tunable optical properties for spin-on-silicon hardmask materials

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jin-Kyu; Dao, Tung Duy; Kim, Ye-Seul; Jeong, Hyun-Dam, E-mail: hdjeong@chonnam.ac.kr

    2016-09-15

    Organic-inorganic hybrid materials with high refractive index have attracted considerable attention for many optoelectronic applications, including spin-on-type hardmask for ArF lithography (193 nm). In this study, we demonstrate the synthesis of a C{sub 60}-embedded organosilicon hybrid polymer, C{sub 60}-embedded poly-xylene-hexamethyltrisiloxane hybrid (C{sub 60}-PXS), of tunable optical properties. C{sub 60} was covalently bonded to the PXS backbone through Pt-catalyzed hydrosilylation, in which the PXS was formed possibly by unexpected transition metal-catalyzed benzylic C−H silylation and oxygenation of the o-xylene. The C{sub 60}-PXS thin films fabricated using a spin-coating method showed much higher refractive index by 5–22% according to the curing temperatures, than the PXS thin films containing no C{sub 60}. In particular, the C{sub 60}-PXS thin film cured at 350 °C showed the refractive index (n) and extinction coefficient (k) at 193 nm to be 1.61 and 0.29 that are very close to the optimum values for the Si-hardmask. This implies the high applicability of the C{sub 60}-embedded organosilicon hybrid polymer, C{sub 60}-PXS, for the spin-on Si-hardmask in ArF lithography. - Highlights: • A facile synthetic route for C{sub 60}-embedded organosilicon hybrid polymer was presented. • The hybrid polymer showed much higher refractive index than the polymer without C{sub 60}. • The hybrid polymer is highly applicable for Si-hardmask in terms of optical properties. • It is believed that the properties of the hybrid polymer can be further optimized.

  10. Bismuth modified physical, structural and optical properties of mid-IR transparent zinc boro-tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, R.S.; Dhankhar, Sunil; Punia, R., E-mail: rajeshpoonia13@gmail.com; Nanda, Kirti; Kishore, N.

    2014-02-25

    Highlights: • Novel materials transmitting in mid-infrared spectral region. • Studied glasses may be good candidates for military and non-linear applications. • Hydrogenic excitonic model is applicable. • Transformation of TeO{sub 4} structural units into TeO{sub 3} units with increase in bismuth content. • B{sub 2}O{sub 3} exists in the both BO{sub 3} trigonal and BO{sub 4} tetrahedral structural units. -- Abstract: Tellurium oxide based quaternary glasses in the system TeO{sub 2}⋅B{sub 2}O{sub 3}⋅Bi{sub 2}O{sub 3}⋅ZnO have been prepared by melt quenching technique. Amorphous nature of the samples has been ascertained by X-ray Diffractogram. The values of density and molar volume increase with increase in Bi{sub 2}O{sub 3} content. Theoretical calculations of crystalline volume (V{sub c}) have also been made. The glass transition temperature (T{sub g}) has been determined using differential scanning calorimetry (DSC) and its value is observed to decrease with increase in Bi{sub 2}O{sub 3} content. IR and Raman spectra of the present glass system indicate that ZnO acts as network modifier and exists in ZnO{sub 4} units. TeO{sub 2} exists as TeO{sub 3}, TeO{sub 4}, and TeO{sub 6} structural units and the number of TeO{sub 4} groups decreases with increase in bismuth content except for the glass sample with x = 5, which shows maximum number of TeO{sub 4} structural units among all other studied glass samples and transformation of some of TeO{sub 4} structural units into TeO{sub 3} structural units is observed with increase in bismuth content. Bismuth plays the role of network modifier with BiO{sub 6} octahedral structural units for glass samples with x = 5, 10, and 15, whereas, exists in network forming BiO{sub 3} pyramidal structural units for glass sample with x = 20. B{sub 2}O{sub 3} exists in the form of BO{sub 3} trigonal and BO{sub 4} tetrahedral structural units. The transmittance of the present glasses is observed to be very high (up to 95

  11. Ultra-Broadband Infrared Pulses from a Potassium-Titanyl Phosphate Optical Parametric Amplifier for VIS-IR-SFG Spectroscopy

    Science.gov (United States)

    Isaienko, Oleksandr; Borguet, Eric

    A non-collinear KTP-OPA to provide ultra-broadband mid-infrared pulses was designed and characterized. With proper pulse-front and phase correction, the system has a potential for high-time resolution vibrational VIS-IR-SFG spectroscopy.

  12. Hybrid Micro-Electro-Mechanical Tunable Filter

    Science.gov (United States)

    2007-09-01

    and polymer hybrid actuator and applications as a tunable filter in telecom and in IR chemical detector,” in Micromachining and Microfabrication...consistently achieved. At this temperature, SU8 - SU-8 bonding withstood subsequent processing steps, resulting in a 57% bond yield and an overall 30

  13. Tunable optical switching in the near-infrared spectral regime by employing plasmonic nanoantennas containing phase change materials.

    Science.gov (United States)

    Savaliya, Priten B; Thomas, Arun; Dua, Rishi; Dhawan, Anuj

    2017-10-02

    We propose the design of switchable plasmonic nanoantennas (SPNs) that can be employed for optical switching in the near-infrared regime. The proposed SPNs consist of nanoantenna structures made up of a plasmonic metal (gold) such that these nanoantennas are filled with a switchable material (vanadium dioxide). We compare the results of these SPNs with inverted SPN structures that consist of gold nanoantenna structures surrounded by a layer of vanadium dioxide (VO 2 ) on their outer surface. These nanoantennas demonstrate switching of electric-field intensity enhancement (EFIE) between two states (On and Off states), which can be induced thermally, optically or electrically. The On and Off states of the nanoantennas correspond to the metallic and semiconductor states, respectively of the VO 2 film inside or around the nanoantennas, as the VO 2 film exhibits phase transition from its semiconductor state to the metallic state upon application of thermal, optical, or electrical energy. We employ finite-difference time-domain (FDTD) simulations to demonstrate switching in the EFIE for four different SPN geometries - nanorod-dipole, bowtie, planar trapezoidal toothed log-periodic, and rod-disk - and compare their near-field distributions for the On and Off states of the SPNs. We also demonstrate that the resonance wavelength of the EFIE spectra gets substantially modified when these SPNs switch between the two states.

  14. Hybrid nanomaterial and its applications: IR sensing and energy harvesting

    Science.gov (United States)

    Tseng, Yi-Hsuan

    In this dissertation, a hybrid nanomaterial, single-wall carbon nanotubes-copper sulfide nanoparticles (SWNTs-CuS NPs), was synthesized and its properties were analyzed. Due to its unique optical and thermal properties, the hybrid nanomaterial exhibited great potential for infrared (IR) sensing and energy harvesting. The hybrid nanomaterial was synthesized with the non-covalent bond technique to functionalize the surface of the SWNTs and bind the CuS nanoparticles on the surface of the SWNTs. For testing and analyzing the hybrid nanomaterial, SWNTs-CuS nanoparticles were formed as a thin film structure using the vacuum filtration method. Two conductive wires were bound on the ends of the thin film to build a thin film device for measurements and analyses. Measurements found that the hybrid nanomaterial had a significantly increased light absorption (up to 80%) compared to the pure SWNTs. Moreover, the hybrid nanomaterial thin film devices exhibited a clear optical and thermal switching effect, which could be further enhanced up to ten times with asymmetric illumination of light and thermal radiation on the thin film devices instead of symmetric illumination. A simple prototype thermoelectric generator enabled by the hybrid nanomaterials was demonstrated, indicating a new route for achieving thermoelectricity. In addition, CuS nanoparticles have great optical absorption especially in the near-infrared region. Therefore, the hybrid nanomaterial thin films also have the potential for IR sensing applications. The first application to be covered in this dissertation is the IR sensing application. IR thin film sensors based on the SWNTs-CuS nanoparticles hybrid nanomaterials were fabricated. The IR response in the photocurrent of the hybrid thin film sensor was significantly enhanced, increasing the photocurrent by 300% when the IR light illuminates the thin film device asymmetrically. The detection limit could be as low as 48mW mm-2. The dramatically enhanced

  15. A IR-Femtosecond Laser Hybrid Sensor to Measure the Thermal Expansion and Thermo-Optical Coefficient of Silica-Based FBG at High Temperatures.

    Science.gov (United States)

    Li, Litong; Lv, Dajuan; Yang, Minghong; Xiong, Liangming; Luo, Jie

    2018-01-26

    In this paper, a hybrid sensor was fabricated using a IR-femtosecond laser to measure the thermal expansion and thermo-optical coefficient of silica-based fiber Bragg gratings (FBGs). The hybrid sensor was composed of an inline fiber Fabry-Perot interferometer (FFPI) cavity and a type-II FBG. Experiment results showed that the type-II FBG had three high reflectivity resonances in the wavelength ranging from 1100 to 1600 nm, showing the peaks in 1.1, 1.3 and 1.5 μm, respectively. The thermal expansion and thermo-optical coefficient (1.3 μm, 1.5 μm) of silica-based FBG, under temperatures ranging from 30 to 1100 °C, had been simultaneously calculated by measuring the wavelength of the type-II FBG and FFPI cavity length.

  16. Quadrupolar, emission-tunable pi-expanded 1,4-dihydropyrrolo 3,2-b pyrroles - synthesis and optical properties

    DEFF Research Database (Denmark)

    Janiga, A.; Bednarska, D.; Thorsted, B.

    2014-01-01

    elucidated by comparison with simpler tetraaryl-analogues. The strong charge-transfer characteristic of these functional dyes can be illustrated by large Stokes shifts (4100-7100 cm(-1)) for A-D-A architectures. The replacement of phenyl rings at positions 2 and 5 with the arylethynylaryl substituents......The synthesis and optical characterization of six novel heteroaromatic-based chromophores is described. The new dyes present mostly an A-D-A general framework, where A is an electron-deficient aromatic ring and D is an electron-rich pyrrolo[3,2-b] pyrrole moiety, linked via triple bonds...

  17. Tunable Electrical and Optical Characteristics in Monolayer Graphene and Few-Layer MoS2 Heterostructure Devices.

    Science.gov (United States)

    Rathi, Servin; Lee, Inyeal; Lim, Dongsuk; Wang, Jianwei; Ochiai, Yuichi; Aoki, Nobuyuki; Watanabe, Kenji; Taniguchi, Takashi; Lee, Gwan-Hyoung; Yu, Young-Jun; Kim, Philip; Kim, Gil-Ho

    2015-08-12

    Lateral and vertical two-dimensional heterostructure devices, in particular graphene-MoS2, have attracted profound interest as they offer additional functionalities over normal two-dimensional devices. Here, we have carried out electrical and optical characterization of graphene-MoS2 heterostructure. The few-layer MoS2 devices with metal electrode at one end and monolayer graphene electrode at the other end show nonlinearity in drain current with drain voltage sweep due to asymmetrical Schottky barrier height at the contacts and can be modulated with an external gate field. The doping effect of MoS2 on graphene was observed as double Dirac points in the transfer characteristics of the graphene field-effect transistor (FET) with a few-layer MoS2 overlapping the middle part of the channel, whereas the underlapping of graphene have negligible effect on MoS2 FET characteristics, which showed typical n-type behavior. The heterostructure also exhibits a strongest optical response for 520 nm wavelength, which decreases with higher wavelengths. Another distinct feature observed in the heterostructure is the peak in the photocurrent around zero gate voltage. This peak is distinguished from conventional MoS2 FETs, which show a continuous increase in photocurrent with back-gate voltage. These results offer significant insight and further enhance the understanding of the graphene-MoS2 heterostructure.

  18. Optically stabilized Erbium fiber frequency comb with hybrid mode-locking and a broad tunable range of repetition rate.

    Science.gov (United States)

    Yang, Honglei; Wu, Xuejian; Zhang, Hongyuan; Zhao, Shijie; Yang, Lijun; Wei, Haoyun; Li, Yan

    2016-12-01

    We present an optically stabilized Erbium fiber frequency comb with a broad repetition rate tuning range based on a hybrid mode-locked oscillator. We lock two comb modes to narrow-linewidth reference lasers in turn to investigate the best performance of control loops. The control bandwidth of fast and slow piezoelectric transducers reaches 70 kHz, while that of pump current modulation with phase-lead compensation is extended to 32 kHz, exceeding laser intrinsic response. Eventually, simultaneous lock of both loops is realized to totally phase-stabilize the comb, which will facilitate precision dual-comb spectroscopy, laser ranging, and timing distribution. In addition, a 1.8-MHz span of the repetition rate is achieved by an automatic optical delay line that is helpful in manufacturing a secondary comb with a similar repetition rate. The oscillator is housed in a homemade temperature-controlled box with an accuracy of ±0.02  K, which not only keeps high signal-to-noise ratio of the beat notes with reference lasers, but also guarantees self-starting at the same mode-locking every time.

  19. Tunability and Power Characteristics of the LEBRA Infrared FEL

    CERN Document Server

    Tanaka, Toshinari; Hayakawa, Yasushi; Mori, Akira; Nogami, Kyoko; Sato, Isamu; Yokoyama, Kazue

    2004-01-01

    Application of the infrared (IR) Free-Electron Laser (FEL) was started in October 2003 at the Laboratory for Electron Beam Research and Application (LEBRA) of Nihon University. The FEL system consisted of silver-coated copper mirrors has demonstrated wavelength tunability ranged from 940 to 6100 nm as a function of the electron energy and the undulator K-value. Wavelength dependence of the FEL output power has been measured in term of different electron beam currents, electron energies and the undulator K-values. Approximate 25 mJ/macropulse has been obtained in the range 2 to 3 microns, which corresponds to peak power of 2 MW, provided that the FEL pulse length is 0.4 ps as resulted from the measurement by an interferometric method. The power decrease observed in the longer wavelength range is due to a large diffraction loss in the FEL guiding optics and the vacuum ducts.

  20. Optically Immersed Bolometer IR Detectors Based on V2O5 Thin Films with Polyimide Thermal Impedance Control Layer for Space Applications

    Science.gov (United States)

    Sumesh, M. A.; Thomas, Beno; Vijesh, T. V.; Mohan Rao, G.; Viswanathan, M.; Karanth, S. P.

    2018-01-01

    Optically immersed bolometer IR detectors were fabricated using electron beam evaporated vanadium oxide as the sensing material. Spin-coated polyimide was used as medium to optically immerse the sensing element to the flat surface of a hemispherical germanium lens. This optical immersion layer also serves as the thermal impedance control layer and decides the performance of the devices in terms of responsivity and noise parameters. The devices were packaged in suitable electro-optical packages and the detector parameters were studied in detail. Thermal time constant varies from 0.57 to 6.0 ms and responsivity from 75 to 757 V W-1 corresponding to polyimide thickness in the range 2 to 70 μm for a detector bias of 9 V in the wavelength region of 14-16 μm. Highest D* obtained was 1.2×108 cmHz1/2 W-1. Noise equivalent temperature difference (NETD) of 20 mK was achieved for devices with polyimide thickness more than 32 μm. The figure of merit, NETD × τ product which describes trade-off between thermal time constant and sensitivity is also extensively studied for devices having different thickness of thermal impedance layers.

  1. Enhanced Performance & Functionality of Tunable Delay Lines

    Science.gov (United States)

    2012-08-01

    Based Tunable Optical Delays”, Optics Letters, Vol. 33, Issue 13, pp. 1518-1520 (2008). 2. Louis Christen, Irfan Fazal , Omer F. Yilmaz, Xiaoxia Wu...2008. 3. Omer F. Yilmaz, Louis Christen, Xiaoxia Wu, Scott R. Nuccio, Irfan Fazal , and Alan E. Willner, “Time-Slot-Interchange of 40 Gb/s Variable...F. Yilmaz, S. Khaleghi, L. Christen, I. Fazal , and A. E. Willner, “503 ns, Tunable Optical Delay of 40 Gb/s RZ-OOK using Additional λ-Conversion

  2. Infrared frequency-tunable coherent thermal sources

    International Nuclear Information System (INIS)

    Wang, Hao; Yang, Yue; Wang, Liping

    2015-01-01

    In this work, we numerically demonstrate an infrared (IR) frequency-tunable selective thermal emitter made of graphene-covered silicon carbide (SiC) gratings. Rigorous coupled-wave analysis shows temporally-coherent emission peaks associated with magnetic polariton (MP), whose resonance frequency can be dynamically tuned within the phonon absorption band of SiC by varying graphene chemical potential. An analytical inductor–capacitor circuit model is introduced to quantitatively predict the resonance frequency and further elucidate the mechanism for the tunable emission peak. The effects of grating geometric parameters, such as grating height, groove width and grating period, on the selective emission peak are explored. The direction-independent behavior of MP and associated coherent emission are also demonstrated. Moreover, by depositing four layers of graphene sheets onto the SiC gratings, a large tunability of 8.5% in peak frequency can be obtained to yield the coherent emission covering a broad frequency range from 820 to 890 cm −1 . The novel tunable metamaterial could pave the way to a new class of tunable thermal sources in the IR region. (paper)

  3. Low temperature synthesis, characterization and tunable optical properties of Eu3+, Tb3+ doped CaMoO4 nanoparticles

    International Nuclear Information System (INIS)

    Sharma, K. Gayatri; Singh, Th. Prasanta; Singh, N. Rajmuhon

    2014-01-01

    Highlights: • Red and green nanophosphors of CaMoO 4 :Eu 3+ and Tb 3+ were synthesized via an ethylene glycol route at very low temperature. • The prepared nanoparticles have tetragonal structure. • The luminescence properties of the nanoparticles are also studied extensively. • CIE chromaticity coordinates of the phosphors are also studied. • The blue-green emission of host could be easily tuned to red or green by varying the dopant ion used in the host. - Abstract: CaMoO 4 doped with Eu 3+ and Tb 3+ nanoparticles are obtained using ethylene glycol as the solvent. The synthesis has been carried out at 130 °C temperature. The XRD patterns reveal that all the doped samples are well assigned to the scheelite structure of the CaMoO 4 phase. Upon excitation by ultraviolet radiation, the CaMoO 4 :Eu 3+ , Tb 3+ phosphors show the characteristic emission lines of Eu 3+ and Tb 3+ . For Eu 3+ doped samples, red emission dominates over other transitions and for Tb 3+ doped, green emission is the predominant one. The blue-green emission of the host could be easily tuned to red and green by doping with activator ions. The emission intensity is also dependent on the concentration of the dopant ions. The prepared nanoparticles could find applications in LEDs and other optical devices

  4. Optical Determination of Lead Chrome Green in Green Tea by Fourier Transform Infrared (FT-IR Transmission Spectroscopy.

    Directory of Open Access Journals (Sweden)

    Xiaoli Li

    Full Text Available The potential of Fourier transform infrared (FT-IR transmission spectroscopy for determination of lead chrome green in green tea was investigated based on chemometric methods. Firstly, the qualitative analysis of lead chrome green in tea was performed based on partial least squares discriminant analysis (PLS-DA, and the correct rate of classification was 100%. And then, a hybrid method of interval partial least squares (iPLS regression and successive projections algorithm (SPA was proposed to select characteristic wavenumbers for the quantitative analysis of lead chrome green in green tea, and 19 wavenumbers were obtained finally. Among these wavenumbers, 1384 (C = C, 1456, 1438, 1419(C = N, and 1506 (CNH cm-1 were the characteristic wavenumbers of lead chrome green. Then, these 19 wavenumbers were used to build determination models. The best model was achieved by least squares support vector machine (LS-SVMalgorithm with high coefficient of determination and low root-mean square error of prediction set (R2p = 0.864 and RMSEP = 0.291. All these results indicated the feasibility of IR spectra for detecting lead chrome green in green tea.

  5. Pressure controlled tunable magnetic, electrical and optical properties of (Cu, Li)-codoped ZnO thin films

    Science.gov (United States)

    Zhang, Liqiang; Lu, Bin; Ye, Zhizhen; Lu, Jianguo; Huang, Jingyun

    2013-09-01

    Zn0.989Cu0.01Li0.001O thin films have been deposited on c-plane sapphire substrates by pulsed laser deposition (PLD). The films deposited at 500 °C and the oxygen pressures (PO2) ranging from 0.04 to 40 Pa were of good crystallinity with a (0002) preferential orientation. Three conductivity regimes were observed for the films with varying the PO2. The n-type film obtained at 0.04 Pa had a low resistivity of 1.95×10-2 Ω cm, Hall mobility of 14.8 cm2 V-1 s-1, and carrier concentration of 2.16×1019 cm-3. The p-type Zn0.989Cu0.01Li0.001O film could achieve when oxygen ambient reached as high as 40 Pa and with a hole concentration of 1.12×1018 cm-3. Films grown at PO2 between 0.4 and 4 Pa commonly exhibited insulating behavior. All the Zn0.989Cu0.01Li0.001O films had a high transmittance above 80% in visible regions and the red-shift in optical band gap (Eg) happened as the PO2 increased. Magnetic measurements showed that only the film fabricated at 0.04 Pa with n-type conduction exhibited room temperature ferromagnetism (RTFM) of 0.25μB/Cu while others obtained at higher PO2 were paramagnetic. Oxygen vacancies (VO) are speculated that would play a crucial role for the ferromagnetic behavior observed.

  6. Development and implementation of a remote audit tool for high dose rate (HDR) Ir-192 brachytherapy using optically stimulated luminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Casey, Kevin E.; Kry, Stephen F.; Howell, Rebecca M.; Followill, David [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); Alvarez, Paola; Lawyer, Ann [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2013-11-15

    Purpose: The aim of this work was to create a mailable phantom with measurement accuracy suitable for Radiological Physics Center (RPC) audits of high dose-rate (HDR) brachytherapy sources at institutions participating in National Cancer Institute-funded cooperative clinical trials. Optically stimulated luminescence dosimeters (OSLDs) were chosen as the dosimeter to be used with the phantom.Methods: The authors designed and built an 8 × 8 × 10 cm{sup 3} prototype phantom that had two slots capable of holding Al{sub 2}O{sub 3}:C OSLDs (nanoDots; Landauer, Glenwood, IL) and a single channel capable of accepting all {sup 192}Ir HDR brachytherapy sources in current clinical use in the United States. The authors irradiated the phantom with Nucletron and Varian {sup 192}Ir HDR sources in order to determine correction factors for linearity with dose and the combined effects of irradiation energy and phantom characteristics. The phantom was then sent to eight institutions which volunteered to perform trial remote audits.Results: The linearity correction factor was k{sub L}= (−9.43 × 10{sup −5}× dose) + 1.009, where dose is in cGy, which differed from that determined by the RPC for the same batch of dosimeters using {sup 60}Co irradiation. Separate block correction factors were determined for current versions of both Nucletron and Varian {sup 192}Ir HDR sources and these vendor-specific correction factors differed by almost 2.6%. For the Nucletron source, the correction factor was 1.026 [95% confidence interval (CI) = 1.023–1.028], and for the Varian source, it was 1.000 (95% CI = 0.995–1.005). Variations in lateral source positioning up to 0.8 mm and distal/proximal source positioning up to 10 mm had minimal effect on dose measurement accuracy. The overall dose measurement uncertainty of the system was estimated to be 2.4% and 2.5% for the Nucletron and Varian sources, respectively (95% CI). This uncertainty was sufficient to establish a ±5% acceptance

  7. Development and implementation of a remote audit tool for high dose rate (HDR) Ir-192 brachytherapy using optically stimulated luminescence dosimetry

    International Nuclear Information System (INIS)

    Casey, Kevin E.; Kry, Stephen F.; Howell, Rebecca M.; Followill, David; Alvarez, Paola; Lawyer, Ann

    2013-01-01

    Purpose: The aim of this work was to create a mailable phantom with measurement accuracy suitable for Radiological Physics Center (RPC) audits of high dose-rate (HDR) brachytherapy sources at institutions participating in National Cancer Institute-funded cooperative clinical trials. Optically stimulated luminescence dosimeters (OSLDs) were chosen as the dosimeter to be used with the phantom.Methods: The authors designed and built an 8 × 8 × 10 cm 3 prototype phantom that had two slots capable of holding Al 2 O 3 :C OSLDs (nanoDots; Landauer, Glenwood, IL) and a single channel capable of accepting all 192 Ir HDR brachytherapy sources in current clinical use in the United States. The authors irradiated the phantom with Nucletron and Varian 192 Ir HDR sources in order to determine correction factors for linearity with dose and the combined effects of irradiation energy and phantom characteristics. The phantom was then sent to eight institutions which volunteered to perform trial remote audits.Results: The linearity correction factor was k L = (−9.43 × 10 −5 × dose) + 1.009, where dose is in cGy, which differed from that determined by the RPC for the same batch of dosimeters using 60 Co irradiation. Separate block correction factors were determined for current versions of both Nucletron and Varian 192 Ir HDR sources and these vendor-specific correction factors differed by almost 2.6%. For the Nucletron source, the correction factor was 1.026 [95% confidence interval (CI) = 1.023–1.028], and for the Varian source, it was 1.000 (95% CI = 0.995–1.005). Variations in lateral source positioning up to 0.8 mm and distal/proximal source positioning up to 10 mm had minimal effect on dose measurement accuracy. The overall dose measurement uncertainty of the system was estimated to be 2.4% and 2.5% for the Nucletron and Varian sources, respectively (95% CI). This uncertainty was sufficient to establish a ±5% acceptance criterion for source strength audits under a

  8. UV-Vis-IR spectral complex refractive indices and optical properties of brown carbon aerosol from biomass burning

    Science.gov (United States)

    Sumlin, Benjamin J.; Heinson, Yuli W.; Shetty, Nishit; Pandey, Apoorva; Pattison, Robert S.; Baker, Stephen; Hao, Wei Min; Chakrabarty, Rajan K.

    2018-02-01

    Constraining the complex refractive indices, optical properties and size of brown carbon (BrC) aerosols is a vital endeavor for improving climate models and satellite retrieval algorithms. Smoldering wildfires are the largest source of primary BrC, and fuel parameters such as moisture content, source depth, geographic origin, and fuel packing density could influence the properties of the emitted aerosol. We measured in situ spectral (375-1047 nm) optical properties of BrC aerosols emitted from smoldering combustion of Boreal and Indonesian peatlands across a range of these fuel parameters. Inverse Lorenz-Mie algorithms used these optical measurements along with simultaneously measured particle size distributions to retrieve the aerosol complex refractive indices (m = n + iκ). Our results show that the real part n is constrained between 1.5 and 1.7 with no obvious functionality in wavelength (λ), moisture content, source depth, or geographic origin. With increasing λ from 375 to 532 nm, κ decreased from 0.014 to 0.003, with corresponding increase in single scattering albedo (SSA) from 0.93 to 0.99. The spectral variability of κ follows the Kramers-Kronig dispersion relation for a damped harmonic oscillator. For λ ≥ 532 nm, both κ and SSA showed no spectral dependency. We discuss differences between this study and previous work. The imaginary part κ was sensitive to changes in FPD, and we hypothesize mechanisms that might help explain this observation.

  9. Optical losses in p-type layers of GaN ridge waveguides in the IR region

    Science.gov (United States)

    Westreich, Ohad; Katz, Moti; Atar, Gil; Paltiel, Yossi; Sicron, Noam

    2017-07-01

    Optical losses in c-plane (0001) GaN ridge waveguides, containing Mg-doped layers, were measured at 1064 nm, using the Fabry-Perot method. The losses increase linearly with the modal content of the p-layer, indicating that the absorption in these waveguides is dominated by p-layer absorption. The p-layer absorption is strongly anisotropic with E⊥c losses 4 times higher than E∥c. The absorption is temperature independent between 10 °C and 60 °C, supporting the possibility that it is related to Mg-bound holes.

  10. Asbestos as 'toxic short-circuit' optic-fibre for UV within the cell-net: — Likely roles and hazards for secret UV and IR metabolism

    International Nuclear Information System (INIS)

    Traill, Robert R

    2011-01-01

    The most toxic asbestos fibres have widths 250nm-10nm, and this toxicity is 'physical', which could mean either mechanical or optical: Tangling with chromosomes is a mechanical hazard occasionally reported, and fibres 100nm wide — or chrysotile (white asbestos) is >150nm. In both cases, UV A /UV B -transmission would then predominate. (Chrysotile 150nm might be benign — escaping both mechanical and optical!). But what would generate such UV, and why would its transmission be toxic? Thar and Kühl (J.Theor.Biol.:2004) explain that the long mitochondria on microtubules may be able to act as UV-lasers, (and many observers since Gurwitsch 1923 have reported ultraweak UV emissions escaping from all types of living bio-tissue). That all suggests some universal secret role for UV, apparently related to mitosis. Insertion of fibre 'short-circuits' could then cause upsets in mitosis-control, and hence DNA irregularities. Such UV-control could parallel similar lower-powered Infra-Red control-systems (as considered elsewhere for coaxial myelin; or as portrayed by G.Albrecht-Buehler's online animations etc.); and the traditional short mitochondria seem better suited for this IR task.

  11. Development of frequency tunable gyrotrons for plasma diagnostics

    International Nuclear Information System (INIS)

    Idehara, T.; Mitsudo, S.; Sabchevski, S.; Glyavin, M.; Ogawa, I.; Sato, M.; Kawahata, K.; Brand, G.F.

    2000-01-01

    Development of two types of frequency tunable gyrotrons are described. One is frequency step-tunable gyrotrons (Gyrotron FU Series) which cover wide range from millimeter to submillimeter wavelength region. The other is a quasi-optical gyrotron operating in 90 and 180 GHz bands. Both are applicable for plasma diagnostics as power sources. (author)

  12. Tunable Optical Polymer Systems (TOPS)

    Science.gov (United States)

    2001-05-01

    I !· I 90% Methanol: 10"/o water \\ I v tl ;I !I I I ~yy CCI’Il 7 6 5 3 2 Figare 9: 1H-NMR.spectraofthc Trimer ofMEH-PPV in 100% mcthaDol...alongside oligomers) 0 Constant potential electrolyses : [ox] + A B Potentiai/V e-/mol A B 0.75 0.96 0.04 0.85 1.09 0.49 0.51 0.85 2.02 0.03...dibromopropane K2C03, acetone, 70°C H~ ~ + 0 ~ 20c,e ~ !\\ OH 40% Trimethylamine in water , ethanol, acetone Br \\ I -rCie Pd(PPh3)4 , Cui, DMF

  13. Discretely tunable micromachined injection-locked lasers

    International Nuclear Information System (INIS)

    Cai, H; Yu, M B; Lo, G Q; Kwong, D L; Zhang, X M; Liu, A Q; Liu, B

    2010-01-01

    This paper reports a micromachined injection-locked laser (ILL) to provide tunable discrete wavelengths. It utilizes a non-continuously tunable laser as the master to lock a Fabry–Pérot semiconductor laser chip. Both lasers are integrated into a deep-etched silicon chip with dimensions of 3 mm × 3 mm × 0.8 mm. Based on the experimental results, significant improvements in the optical power and spectral purity have been achieved in the fully locked state, and optical hysteresis and bistability have also been observed in response to the changes of the output wavelength and optical power of the master laser. As a whole system, the micromachined ILL is able to provide single mode, discrete wavelength tuning, high power and direct modulation with small size and single-chip solution, making it promising for advanced optical communications such as wavelength division multiplexing optical access networks.

  14. On-line monitoring of methanol and methyl formate in the exhaust gas of an industrial formaldehyde production plant by a mid-IR gas sensor based on tunable Fabry-Pérot filter technology.

    Science.gov (United States)

    Genner, Andreas; Gasser, Christoph; Moser, Harald; Ofner, Johannes; Schreiber, Josef; Lendl, Bernhard

    2017-01-01

    On-line monitoring of key chemicals in an industrial production plant ensures economic operation, guarantees the desired product quality, and provides additional in-depth information on the involved chemical processes. For that purpose, rapid, rugged, and flexible measurement systems at reasonable cost are required. Here, we present the application of a flexible mid-IR filtometer for industrial gas sensing. The developed prototype consists of a modulated thermal infrared source, a temperature-controlled gas cell for absorption measurement and an integrated device consisting of a Fabry-Pérot interferometer and a pyroelectric mid-IR detector. The prototype was calibrated in the research laboratory at TU Wien for measuring methanol and methyl formate in the concentration ranges from 660 to 4390 and 747 to 4610 ppmV. Subsequently, the prototype was transferred and installed at the project partner Metadynea Austria GmbH and linked to their Process Control System via a dedicated micro-controller and used for on-line monitoring of the process off-gas. Up to five process streams were sequentially monitored in a fully automated manner. The obtained readings for methanol and methyl formate concentrations provided useful information on the efficiency and correct functioning of the process plant. Of special interest for industry is the now added capability to monitor the start-up phase and process irregularities with high time resolution (5 s).

  15. Optical Path Length Calibration: A Standard Approach for Use in Absorption Cell-Based IR-Spectrometric Gas Analysis

    Directory of Open Access Journals (Sweden)

    Javis Anyangwe Nwaboh

    2014-01-01

    Full Text Available We employed a comparison method to determine the optical path length of gas cells which can be used in spectroscopic setup based on laser absorption spectroscopy or FTIR. The method is based on absorption spectroscopy itself. A reference gas cell, whose length is a priori known and desirably traceable to the international system of units (SI, and a gas mixture are used to calibrate the path length of a cell under test. By comparing spectra derived from pressure-dependent measurements on the two cells, the path length of the gas cell under test is determined. The method relies neither on the knowledge of the gas concentration nor on the line strength parameter of the probed transition which is very rarely traceable to the SI and of which the uncertainty is often relatively large. The method is flexible such that any infrared light source and infrared active molecule with isolated lines can be used. We elaborate on the method, substantiate the method by reporting results of this calibration procedure applied to multipass and single pass gas cells of lengths from 0.38 m to 21 m, and compare this to other methods. The relative combined uncertainty of the path length results determined using the comparison method was found to be in the ±0.4% range.

  16. Synthesis and XRD, FT-IR vibrational, UV-vis, and nonlinear optical exploration of novel tetra substituted imidazole derivatives: A synergistic experimental-computational analysis

    Science.gov (United States)

    Ahmad, Muhammad Saeed; Khalid, Muhammad; Shaheen, Muhammad Ashraf; Tahir, Muhammad Nawaz; Khan, Muhammad Usman; Braga, Ataualpa Albert Carmo; Shad, Hazoor Ahmad

    2018-04-01

    Heterocyclic compounds have potential applications in many fields of life. We synthesized novel tetra substituted imidazoles by four-component condensation of benzil, substituted aldehydes, substituted anilines and ammonium acetate as a source of ammonia and acetic acid as the solvent. Their chemical structures were resolved through X-ray crystallographic and spectroscopic (Fourier transform IR and UV-vis) techniques. In addition to experimental analysis, density functional theory (DFT) calculations at the B3LYP/6-311 + G(d,p) level were performed on 4-bromo-2-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazole-2-yl)phenol (1), 4-bromo-2-(1-(1-naphthalen-yl)-4,5-diphenyl-1H-imidazole-2-yl)phenol (2), and 2-(1-(2-chlorophenyl)-4,5-diphenyl-1-H-imidazole-2-yl)-6-methoxyphenol (3) to obtain the optimized geometry and spectroscopic (Fourier transform IR and UV-vis) and non-linear optical properties. Frontier molecular orbital analysis was performed at the Hartee-Fock/6-311+g(d,p) and DFT/B3LYP/6-311+G(d,p) levels of theory. Natural bond orbital (NBO) and UV-vis spectral analyses were performed at the M06-2X/6-31+G(d,p) and time-dependent DFT/B3LYP/6-311+G(d,p) levels, respectively. Overall, the DFT findings show good agreement with the experimental data. The hyper conjugative interaction network, which is responsible for the stability of compounds 1, 2 and 3 was explored by the NBO approach. The global reactivity parameters were explored with use of the energy of the frontier molecular orbitals. DFT calculations predict the first-order hyperpolarizabilities of compounds 1, 2 and 3 are 294.89 × 10-30, 219.45 × 10-30 and 146.77 × 10-30 esu, respectively. A two-state model was used to describe the non-linear optical properties of the compounds investigated.

  17. Andromeda (M31) optical and infrared disk survey. I. Insights in wide-field near-IR surface photometry

    International Nuclear Information System (INIS)

    Sick, Jonathan; Courteau, Stéphane; Cuillandre, Jean-Charles; McDonald, Michael; De Jong, Roelof; Tully, R. Brent

    2014-01-01

    We present wide-field near-infrared J and K s images of the Andromeda Galaxy (M31) taken with WIRCam at the Canada-France-Hawaii Telescope as part of the Andromeda Optical and Infrared Disk Survey. This data set allows simultaneous observations of resolved stars and near-infrared (NIR) surface brightness across M31's entire bulge and disk (within R = 22 kpc), permitting a direct test of the stellar composition of near-infrared light in a nearby galaxy. Here we develop NIR observation and reduction methods to recover a uniform surface brightness map across the 3° × 1° disk of M31 with 27 WIRCam fields. Two sky-target nodding strategies are tested, and we find that strictly minimizing sky sampling latency cannot improve background subtraction accuracy to better than 2% of the background level due to spatio-temporal variations in the NIR skyglow. We fully describe our WIRCam reduction pipeline and advocate using flats built from night-sky images over a single night, rather than dome flats that do not capture the WIRCam illumination field. Contamination from scattered light and thermal background in sky flats has a negligible effect on the surface brightness shape compared to the stochastic differences in background shape between sky and galaxy disk fields, which are ∼0.3% of the background level. The most dramatic calibration step is the introduction of scalar sky offsets to each image that optimizes surface brightness continuity. Sky offsets reduce the mean surface brightness difference between observation blocks from 1% to <0.1% of the background level, though the absolute background level remains statistically uncertain to 0.15% of the background level. We present our WIRCam reduction pipeline and performance analysis to give specific recommendations for the improvement of NIR wide-field imaging methods.

  18. Communication: IR spectroscopy of neutral transition metal clusters through thermionic emission

    NARCIS (Netherlands)

    Lapoutre, V. J. F.; Haertelt, M.; Meijer, G.; Fielicke, A.; Bakker, J. M.

    2013-01-01

    The resonant multiple photon excitation of neutral niobium clusters using tunable infrared (IR) radiation leads to thermionic emission. By measuring the mass-resolved ionization yield as a function of IR wavenumber species selective IR spectra are obtained for Nb-n (n = 5-20) over the 200-350 cm(-1)

  19. Optimization of a dual-rotating-retarder polarimeter as applied to a tunable infrared Mueller-matrix scatterometer

    International Nuclear Information System (INIS)

    Vap, J C; Nauyoks, S E; Marciniak, M A

    2013-01-01

    The value of Mueller-matrix (Mm) scatterometers lies in their ability to simultaneously characterize the polarimetric and directional scatter properties of a sample. To extend their utility to characterizing modern optical materials in the infrared (IR), which often have very narrow resonances yet interesting polarization and directional properties, the addition of tunable IR lasers and an achromatic dual-rotating-retarder (DRR) polarimeter is necessary. An optimization method has been developed for use with the tunable IR Mm scatterometer. This method is rooted in the application of random error analysis to three different DRR retardances, λ/5, λ/4 and λ/3, for three different analyzer (A)-to-generator (G) retarder rotation ratios, θ A :θ G = 34:26, 25:5 and 37.5:7.5, and a variable number of intensity measurements. The product of the error analysis is in terms of the level of error that could be expected from a free-space Mm extraction for the various retardances, retarder rotation ratios and number of intensity measurements of the DRR. The optimal DRR specifications identified are a λ/3 retardance and a Fourier rotation ratio, with the number of required collected measurements dependent on the level of error acceptable to the user. Experimental results corroborate this error analysis using an achromatic 110-degree retardance-configured DRR polarimeter at 5 µm wavelength, which resulted in consistent 1% error in its free-space Mm extractions. (paper)

  20. Characterization of WO3-doped borophosphate glasses by optical, IR and ESR spectroscopic techniques before and after subjecting to gamma irradiation

    International Nuclear Information System (INIS)

    Ouis, M.A.; EI-Batal, H.A.; Azooz, M.A.; Abdelghany, A.M.

    2013-01-01

    Borophosphate glasses containing increasing WO 3 within the doping level (0.16-1.33%) have been prepared and investigated by UV-visible, infrared spectral measurements. These glasses have been exposed to gamma rays with a dose of 8 Mrad for studying the effect of gamma radiation on the combined studied spectra of such glasses. The optical spectrum of undoped borophosphate glass reveals strong UV absorption but with no visible bands. This strong UV absorption is related to the presence of unavoidable trace iron impurities within the chemicals used for the preparation of this borophosphate glass. The WO 3 -doped samples show two additional UV and visible bands at about 380 and 740 nm due to the presence of both W 6+ and W 5+ ions in noticeable content. The calculated induced spectra reveal the appearance of an ultraviolet band at 320 nm and two visible bands centered at 390 and 540 nm which are related to the combined presence of W 6+ and W 5+ ions. The FTIR spectra show vibrational bands due to characteristic constitutional phosphate and borate groups but the phosphate groups are predominant due to the high P 2 O 5 content (50%). The effect of the addition of WO 3 with the dopant level reveals limited changes in the IR spectra. Electron spin resonance (ESR) spectra show specified signals in the high WO 3 content glass but on gamma irradiation the signals are disappeared. This result confirms the decrease of the W 5+ ions by photochemical oxidation to paired W 6+ ions. This result is also observed in optical absorption of WO 3 doped glasses after gamma irradiation through the disappearance of the visible band at 740 nm. (author)

  1. Absolute Distance Measurements with Tunable Semiconductor Laser

    Czech Academy of Sciences Publication Activity Database

    Mikel, Břetislav; Číp, Ondřej; Lazar, Josef

    T118, - (2005), s. 41-44 ISSN 0031-8949 R&D Projects: GA AV ČR(CZ) IAB2065001 Keywords : tunable laser * absolute interferometer Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.661, year: 2004

  2. Application of fiber-optic attenuated total reflection-FT-IR methods for in situ characterization of protein delivery systems in real time.

    Science.gov (United States)

    McFearin, Cathryn L; Sankaranarayanan, Jagadis; Almutairi, Adah

    2011-05-15

    A fiber-optic coupled attenuated total reflection (ATR)-FT-IR spectroscopy technique was applied to the study of two different therapeutic delivery systems, acid degradable hydrogels and nanoparticles. Real time exponential release of a model protein, human serum albumin (HSA), was observed from two different polymeric hydrogels formulated with a pH sensitive cross-linker. Spectroscopic examination of nanoparticles formulated with an acid degradable polymer shell and encapsulated HSA exhibited vibrational signatures characteristic of both particle and payload when exposed to lowered pH conditions, demonstrating the ability of this methodology to simultaneously measure phenomena arising from a system with a mixture of components. In addition, thorough characterization of these pH sensitive delivery vehicles without encapsulated protein was also accomplished in order to separate the effects of the payload during degradation. When in situ, real time detection in combination with the ability to specifically identify different components in a mixture without involved sample preparation and minimal sample disturbance is provided, the versatility and suitability of this type of experiment for research in the pharmaceutical field is demonstrated.

  3. Investigating tunable KRb gases and Bose-Einstein condensates

    DEFF Research Database (Denmark)

    Jørgensen, Nils Byg

    2015-01-01

    We present the production of dual-species Bose-Einstein condensates of 39K and 87Rb with tunable interactions. A dark spontaneous force optical trap was used for 87Rb to reduce the losses in 39K originating from light-assisted collisions in the magneto optical trapping phase. Using sympathetic...... for dual-species condensates with tunable interactions. Employing the dual-species condensates, the miscible to immiscible phase transition was investigated. By applying an empirical model, the transition was used to determine the background scattering length. Two species quantum gases with tunable...

  4. Optical and thermal design of 1.5-m aperture solar UV visible and IR observing telescope for Solar-C mission

    Science.gov (United States)

    Suematsu, Y.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.; Horiuchi, T.; Matsumoto, Y.; Takeyama, N.

    2017-11-01

    The next Japanese solar mission, SOLAR-C, which has been envisaged after successful science operation of Hinode (SOLAR-B) mission, is perusing two plans: plan-A and plan-B, and under extensive study from science objectives as well as engineering point of view. The plan-A aims at performing out-of-ecliptic observations for investigating, with helioseismic approach, internal structure and dynamo mechanisms of the Sun. It also explores polar regions where fast solar wind is believed to originate. A baseline orbit for plan-A is a circular orbit of 1 AU distance from the Sun with its inclination at around or greater than 40 degrees. The plan-B aims to study small-scale plasma processes and structures in the solar atmosphere which attract researchers' growing interest, followed by many Hinode discoveries [1], for understanding fully dynamism and magnetic nature of the atmosphere. With plan-B, high-angular-resolution investigation of the entire solar atmosphere (from the photosphere to the corona, including their interface layers, i.e., chromosphere and transition region) is to be performed with enhanced spectroscopic and spectro-polarimetric capability as compared with Hinode, together with enhanced sensitivity towards ultra-violet wavelengths. The orbit of plan-B is either a solar synchronous polar orbit of altitude around 600 km or a geosynchronous orbit to ensure continuous solar observations. After the decision of any one of the two plans, the SOLAR-C will be proposed for launch in mid-2010s. In this paper, we will present a basic design of one of major planned instrumental payload for the plan-B: the Solar Ultra-violet Visible and near IR observing Telescope (hereafter referred to as SUVIT). The basic concept in designing the SUVIT is to utilize as much as possible a heritage of successful telescope of the Solar Optical Telescope (SOT) aboard Hinode [2]. Major differences of SUVIT from SOT are the three times larger aperture of 1.5 m, which enables to collect one

  5. Dynamically tunable interface states in 1D graphene-embedded photonic crystal heterostructure

    Science.gov (United States)

    Huang, Zhao; Li, Shuaifeng; Liu, Xin; Zhao, Degang; Ye, Lei; Zhu, Xuefeng; Zang, Jianfeng

    2018-03-01

    Optical interface states exhibit promising applications in nonlinear photonics, low-threshold lasing, and surface-wave assisted sensing. However, the further application of interface states in configurable optics is hindered by their limited tunability. Here, we demonstrate a new approach to generate dynamically tunable and angle-resolved interface states using graphene-embedded photonic crystal (GPC) heterostructure device. By combining the GPC structure design with in situ electric doping of graphene, a continuously tunable interface state can be obtained and its tuning range is as wide as the full bandgap. Moreover, the exhibited tunable interface states offer a possibility to study the correspondence between space and time characteristics of light, which is beyond normal incident conditions. Our strategy provides a new way to design configurable devices with tunable optical states for various advanced optical applications such as beam splitter and dynamically tunable laser.

  6. CCD and IR array controllers

    Science.gov (United States)

    Leach, Robert W.; Low, Frank J.

    2000-08-01

    A family of controllers has bene developed that is powerful and flexible enough to operate a wide range of CCD and IR focal plane arrays in a variety of ground-based applications. These include fast readout of small CCD and IR arrays for adaptive optics applications, slow readout of large CCD and IR mosaics, and single CCD and IR array operation at low background/low noise regimes as well as high background/high speed regimes. The CCD and IR controllers have a common digital core based on user- programmable digital signal processors that are used to generate the array clocking and signal processing signals customized for each application. A fiber optic link passes image data and commands to VME or PCI interface boards resident in a host computer to the controller. CCD signal processing is done with a dual slope integrator operating at speeds of up to one Megapixel per second per channel. Signal processing of IR arrays is done either with a dual channel video processor or a four channel video processor that has built-in image memory and a coadder to 32-bit precision for operating high background arrays. Recent developments underway include the implementation of a fast fiber optic data link operating at a speed of 12.5 Megapixels per second for fast image transfer from the controller to the host computer, and supporting image acquisition software and device drivers for the PCI interface board for the Sun Solaris, Linux and Windows 2000 operating systems.

  7. A ZnGeP{sub 2} Optical Parametric Oscillator with Mid-IR Output Power 3 W Pumped by a Tm, Ho:GdVO{sub 4} Laser

    Energy Technology Data Exchange (ETDEWEB)

    Bao-Quan, Yao; Guo-Li, Zhu; You-Lun, Ju; Yue-Zhu, Wang [National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150080 (China)

    2009-02-15

    We report an efficient mid-infrared optical parametric oscillator (OPO) pumped by a pulsed Tm,Ho-codoped GdVO4 laser. The 10-W Tm,Ho:GdVO4 laser pumped by a 801 nm diode produces 20ns pulses with a repetition rate of 10kHz at wavelength of 2.048 {mu}m. The ZnGeP{sub 2} (ZGP) OPO produces 15-ns pulses in the spectral regions 3.65-3.8 {mu}m and 4.45-4.65 {mu}m simultaneously. More than 3 W of mid-IR output power can be generated with a total OPO slope efficiency greater than 58% corresponding to incident 2 {mu}m pump power. The diode laser pump to mid-IR optical conversion efficiency is about 12%.

  8. An Interferometric Study of the Post-AGB Binary 89 Herculis. 1: Spatially Resolving the Continuum Circumstellar Environment at Optical and Near-IR Wavelengths with the VLTI, NPOI, IOTA, PTI, and the CHARA Array

    Science.gov (United States)

    2013-01-01

    Herculis I. Spatially resolving the continuum circumstellar environment at optical and near-IR wavelengths with the VLTI, NPOI, IOTA , PTI, and the CHARA...public release; distribution unlimited 13. SUPPLEMENTARY NOTES A&A 559, A111 (2013) 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION...Array ( IOTA ) and the Center for High Angular Resolution Astronomy (CHARA) Array, covering 0.5 to 2.2 μm and with baselines from 15 to 278 m. Here we

  9. Preparation and analysis of anodic aluminum oxide films with continuously tunable interpore distances

    Science.gov (United States)

    Qin, Xiufang; Zhang, Jinqiong; Meng, Xiaojuan; Deng, Chenhua; Zhang, Lifang; Ding, Guqiao; Zeng, Hao; Xu, Xiaohong

    2015-02-01

    Nanoporous anodic aluminum oxides are often used as templates for preparation of nanostructures such as nanodot, nanowire and nanotube arrays. The interpore distance of anodic aluminum oxide is the most important parameter in controlling the periodicity of these nanostructures. Herein we demonstrate a simple and yet powerful method to fabricate ordered anodic aluminum oxides with continuously tunable interpore distances. By using mixed solution of citric and oxalic acids with different molar ratio, the range of anodizing voltages within which self-ordered films can be formed were extended to between 40 and 300 V, resulting in the interpore distances change from 100 to 750 nm. Our work realized very broad range of interpore distances in a continuously tunable fashion and the experiment processes are easily controllable and reproducible. The dependence of the interpore distances on acid ratios in mixed solutions was discussed through analysis of anodizing current and it was found that the effective dissociation constant of the mixed acids is of great importance. The interpore distances achieved are comparable to wavelengths ranging from UV to near IR, and may have potential applications in optical meta-materials for photovoltaics and optical sensing.

  10. A Microwave Tunable Bandpass Filter for Liquid Crystal Applications

    Science.gov (United States)

    Cao, Weiping; Jiang, Di; Liu, Yupeng; Yang, Yuanwang; Gan, Baichuan

    2017-07-01

    In this paper, a novel microwave continuously tunable band-pass filter, based on nematic liquid crystals (LCs), is proposed. It uses liquid crystal (LC) as the electro-optic material to mainly realize frequency shift at microwave band by changing the dielectric anisotropy, when applying the bias voltage. According to simulation results, it achieves 840 MHz offset. Comparing to the existing tunable filter, it has many advantages, such as continuously tunable, miniaturization, low processing costs, low tuning voltage, etc. Thus, it has shown great potentials in frequency domain and practical applications in modern communication.

  11. MEMS for Tunable Photonic Metamaterial Applications

    Science.gov (United States)

    Stark, Thomas

    Photonic metamaterials are materials whose optical properties are derived from artificially-structured sub-wavelength unit cells, rather than from the bulk properties of the constituent materials. Examples of metamaterials include plasmonic materials, negative index materials, and electromagnetic cloaks. While advances in simulation tools and nanofabrication methods have allowed this field to grow over the past several decades, many challenges still exist. This thesis addresses two of these challenges: fabrication of photonic metamaterials with tunable responses and high-throughput nanofabrication methods for these materials. The design, fabrication, and optical characterization of a microelectromechanical systems (MEMS) tunable plasmonic spectrometer are presented. An array of holes in a gold film, with plasmon resonance in the mid-infrared, is suspended above a gold reflector, forming a Fabry-Perot interferometer of tunable length. The spectra exhibit the convolution of extraordinary optical transmission through the holes and Fabry-Perot resonances. Using MEMS, the interferometer length is modulated from 1.7 mum to 21.67 mum , thereby tuning the free spectral range from about 2900 wavenumbers to 230.7 wavenumbers and shifting the reflection minima and maxima across the infrared. Due to its broad spectral tunability in the fingerprint region of the mid-infrared, this device shows promise as a tunable biological sensing device. To address the issue of high-throughput, high-resolution fabrication of optical metamaterials, atomic calligraphy, a MEMS-based dynamic stencil lithography technique for resist-free fabrication of photonic metamaterials on unconventional substrates, has been developed. The MEMS consists of a moveable stencil, which can be actuated with nanometer precision using electrostatic comb drive actuators. A fabrication method and flip chip method have been developed, enabling evaporation of metals through the device handle for fabrication on an

  12. Spontaneous emission control in a tunable hybrid photonic system

    NARCIS (Netherlands)

    Frimmer, M.; Koenderink, A.F.

    2013-01-01

    We experimentally demonstrate control of the rate of spontaneous emission in a tunable hybrid photonic system that consists of two canonical building blocks for spontaneous emission control, an optical antenna and a mirror, each providing a modification of the local density of optical states (LDOS).

  13. Mid infra-red hyper-spectral imaging with bright super continuum source and fast acousto-optic tuneable filter for cytological applications

    International Nuclear Information System (INIS)

    Farries, Mark; Ward, Jon; Valle, Stefano; Stephens, Gary; Moselund, Peter; Van der Zanden, Koen; Napier, Bruce

    2015-01-01

    Mid-IR imaging spectroscopy has the potential to offer an effective tool for early cancer diagnosis. Current development of bright super-continuum sources, narrow band acousto-optic tunable filters and fast cameras have made feasible a system that can be used for fast diagnosis of cancer in vivo at point of care. The performance of a proto system that has been developed under the Minerva project is described. (paper)

  14. Tunable plasmonic toroidal terahertz metamodulator

    Science.gov (United States)

    Gerislioglu, Burak; Ahmadivand, Arash; Pala, Nezih

    2018-04-01

    Optical modulators are essential and strategic parts of micro- and nanophotonic circuits to encode electro-optical signals in the optical domain. Here, by using arrays of multipixel toroidal plasmonic terahertz (THz) metamolecules, we developed a functional plasmonic metamodulator with high efficiency and tunability. Technically, the dynamic toroidal dipole induces nonradiating charge-current arrangements leading to have an exquisite role in defining the inherent spectral features of various materials. By categorizing in a different family of multipoles far from the traditional electromagnetic multipoles, the toroidal dipole corresponds to poloidal currents flowing on the surface of a closed-loop torus. Utilizing the sensitivity of the optically driven toroidal momentum to the incident THz beam power and by employing both numerical tools and experimental analysis, we systematically studied the spectral response of the proposed THz plasmonic metadevice. In this Rapid Communication, we uncover a correlation between the existence and the excitation of the toroidal response and the incident beam power. This mechanism is employed to develop THz toroidal metamodulators with a strong potential to be employed for practical advanced and next-generation communication, filtering, and routing applications.

  15. Composition-Tunable Optical Properties of Zn x Cd(1 - x)S Quantum Dot-Carboxymethylcellulose Conjugates: Towards One-Pot Green Synthesis of Multifunctional Nanoplatforms for Biomedical and Environmental Applications

    Science.gov (United States)

    Mansur, Alexandra A. P.; Mansur, Herman S.; Caires, Anderson J.; Mansur, Rafael L.; Oliveira, Luiz C.

    2017-07-01

    Quantum dots (QDs) are colloidal semiconductor nanocrystals with unique properties that can be engineered by controlling the nanoparticle size and chemical composition by doping and alloying strategies. However, due to their potential toxicity, augmenting their biocompatibility is yet a challenge for expanding to several biomedical and environmentally friendly applications. Thus, the main goal of this study was to develop composition-tunable and biocompatible Zn x Cd1 - x S QDs using carboxymethylcellulose polysaccharide as direct capping ligand via green colloidal aqueous route at neutral pH and at room temperature for potential biomedical and environmental applications. The ternary alloyed QDs were extensively characterized using UV-vis spectroscopy, photoluminescence spectroscopy (PL), transmission electron microscopy (TEM), X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), and X-ray photoelectrons spectroscopy (XPS). The results indicated that Zn x Cd(1 - x)S QDs were surface stabilized by carboxymethylcellulose biopolymer with spherical morphology for all composition of alloys and narrow sizes distributions ranging from 4 to 5 nm. The XRD results indicated that monophasic ternary alloyed Zn x Cd1 - x S nanocrystals were produced with homogenous composition of the core as evidenced by EELS and XPS analyses. In addition, the absorption and emission optical properties of Zn x Cd1 - x S QDs were red shifted with increasing the amount of Cd2+ in the alloyed nanocrystals, which have also increased the quantum yield compared to pure CdS and ZnS nanoparticles. These properties of alloyed nanomaterials were interpreted based on empirical model of Vegard's law and chemical bond model (CBM). As a proof of concept, these alloyed-QD conjugates were tested for biomedical and environmental applications. The results demonstrated that they were non-toxic and effective fluorophores for bioimaging live HEK293T cells (human embryonic kidney cells) using confocal

  16. Adaptive IR Sensing Based on Advanced Nanostructures with Tunable Kinetics

    Science.gov (United States)

    2015-11-05

    V compound semiconductor manufacturing. 3. METHODS, ASSUMPTIONS, AND PROCEDURES 3.1. Nanoscale engineering and tuning of electron processes by...found to be 60 – 80 meV. The specific equidistant positions of energy levels may be associated with the quasi- parabolic form of the confinement...4) where τtr is the electron transit time, i.e. the time that an electron spends in the detector moving from the emitter to the collector

  17. Narrow optical linewidths and spin pumping on charge-tunable close-to-surface self-assembled quantum dots in an ultrathin diode

    Science.gov (United States)

    Löbl, Matthias C.; Söllner, Immo; Javadi, Alisa; Pregnolato, Tommaso; Schott, Rüdiger; Midolo, Leonardo; Kuhlmann, Andreas V.; Stobbe, Søren; Wieck, Andreas D.; Lodahl, Peter; Ludwig, Arne; Warburton, Richard J.

    2017-10-01

    We demonstrate full charge control, narrow optical linewidths, and optical spin pumping on single self-assembled InGaAs quantum dots embedded in a 162.5 -nm -thin diode structure. The quantum dots are just 88 nm from the top GaAs surface. We design and realize a p -i -n -i -n diode that allows single-electron charging of the quantum dots at close-to-zero applied bias. In operation, the current flow through the device is extremely small resulting in low noise. In resonance fluorescence, we measure optical linewidths below 2 μ eV , just a factor of 2 above the transform limit. Clear optical spin pumping is observed in a magnetic field of 0.5 T in the Faraday geometry. We present this design as ideal for securing the advantages of self-assembled quantum dots—highly coherent single-photon generation, ultrafast optical spin manipulation—in the thin diodes required in quantum nanophotonics and nanophononics applications.

  18. Tunable diffraction and self-defocusing in liquid-filled photonic crystal fibers

    DEFF Research Database (Denmark)

    Rosberg, Christian Romer; Bennet, Francis H.; Neshev, Dragomir N.

    2007-01-01

    We suggest and demonstrate a novel platform for the study of tunable nonlinear light propagation in two-dimensional discrete systems, based on photonic crystal fibers filled with high index nonlinear liquids. Using the infiltrated cladding region of a photonic crystal fiber as a nonlinear waveguide...... array, we experimentally demonstrate highly tunable beam diffraction and thermal self-defocusing, and realize a compact all-optical power limiter based on a tunable nonlinear response....

  19. Controlling THz and far-IR waves with chiral and bianisotropic metamaterials

    Directory of Open Access Journals (Sweden)

    Kenanakis George

    2015-01-01

    Full Text Available Chiral and bianisotropic metamaterials, where coupling of magnetic and electric phenomena plays an important role, offer advanced possibilities for the control and manipulation of electromagnetic waves. Such a control is particularly useful in the THz and far-IR region where natural materials do not show strong response and thus they are not offered as components for a direct realization of electromagnetic wave manipulation. Among the most useful and important capabilities of chiral and bianisotropic metamaterials is the advanced control of the wave polarization that they offer, including giant polarization rotation, conversion, filtering, absorption, etc. In this paper we review our recent work demonstrating some of those capabilities, in a variety of structures, both planar and 3D-bulk ones. The structures presented show, among others, large optical activity, tunable/switchable wave ellipticity, and polarization-dependent asymmetric transmission.

  20. Sum-Frequency-Generation-Based Laser Sidebands for Tunable Femtosecond Raman Spectroscopy in the Ultraviolet

    Directory of Open Access Journals (Sweden)

    Liangdong Zhu

    2015-04-01

    Full Text Available Femtosecond stimulated Raman spectroscopy (FSRS is an emerging molecular structural dynamics technique for functional materials characterization typically in the visible to near-IR range. To expand its applications we have developed a versatile FSRS setup in the ultraviolet region. We use the combination of a narrowband, ~400 nm Raman pump from a home-built second harmonic bandwidth compressor and a tunable broadband probe pulse from sum-frequency-generation-based cascaded four-wave mixing (SFG-CFWM laser sidebands in a thin BBO crystal. The ground state Raman spectrum of a laser dye Quinolon 390 in methanol that strongly absorbs at ~355 nm is systematically studied as a standard sample to provide previously unavailable spectroscopic characterization in the vibrational domain. Both the Stokes and anti-Stokes Raman spectra can be collected by selecting different orders of SFG-CFWM sidebands as the probe pulse. The stimulated Raman gain with the 402 nm Raman pump is >21 times larger than that with the 550 nm Raman pump when measured at the 1317 cm−1 peak for the aromatic ring deformation and ring-H rocking mode of the dye molecule, demonstrating that pre-resonance enhancement is effectively achieved in the unique UV-FSRS setup. This added tunability in the versatile and compact optical setup enables FSRS to better capture transient conformational snapshots of photosensitive molecules that absorb in the UV range.

  1. Rapid, nondestructive estimation of surface polymer layer thickness using attenuated total reflection fourier transform infrared (ATR FT-IR) spectroscopy and synthetic spectra derived from optical principles.

    Science.gov (United States)

    Weinstock, B André; Guiney, Linda M; Loose, Christopher

    2012-11-01

    We have developed a rapid, nondestructive analytical method that estimates the thickness of a surface polymer layer with high precision but unknown accuracy using a single attenuated total reflection Fourier transform infrared (ATR FT-IR) measurement. Because the method is rapid, nondestructive, and requires no sample preparation, it is ideal as a process analytical technique. Prior to implementation, the ATR FT-IR spectrum of the substrate layer pure component and the ATR FT-IR and real refractive index spectra of the surface layer pure component must be known. From these three input spectra a synthetic mid-infrared spectral matrix of surface layers 0 nm to 10,000 nm thick on substrate is created de novo. A minimum statistical distance match between a process sample's ATR FT-IR spectrum and the synthetic spectral matrix provides the thickness of that sample. We show that this method can be used to successfully estimate the thickness of polysulfobetaine surface modification, a hydrated polymeric surface layer covalently bonded onto a polyetherurethane substrate. A database of 1850 sample spectra was examined. Spectrochemical matrix-effect unknowns, such as the nonuniform and molecularly novel polysulfobetaine-polyetherurethane interface, were found to be minimal. A partial least squares regression analysis of the database spectra versus their thicknesses as calculated by the method described yielded an estimate of precision of ±52 nm.

  2. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  3. Tunable optical properties of plasmonic Au/Al2O3 nanocomposite thin films analyzed by spectroscopic ellipsometry accounting surface characteristics.

    Science.gov (United States)

    Jaiswal, Jyoti; Mourya, Satyendra; Malik, Gaurav; Chandra, Ramesh

    2018-05-01

    In the present work, we have fabricated plasmonic gold/alumina nanocomposite (Au/Al 2 O 3 NC) thin films on a glass substrate at room temperature by RF magnetron co-sputtering. The influence of the film thickness (∼10-40  nm) on the optical and other physical properties of the samples was investigated and correlated with the structural and compositional properties. The X-ray diffractometer measurement revealed the formation of Au nanoparticles with average crystallite size (5-9.2 nm) embedded in an amorphous Al 2 O 3 matrix. The energy-dispersive X ray and X-ray photoelectron spectroscopy results confirmed the formation of Au/Al 2 O 3 NC quantitatively and qualitatively and it was observed that atomic% of Au increased by increasing thickness. The optical constants of the plasmonic Au/Al 2 O 3 NC thin films were examined by variable angle spectroscopic ellipsometry in the wide spectral range of 246-1688 nm, accounting the surface characteristics in the optical stack model, and the obtained results are expected to be unique. Additionally, a thickness-dependent blueshift (631-590 nm) of surface plasmon resonance peak was observed in the absorption spectra. These findings of the plasmonic Au/Al 2 O 3 NC films may allow the design and fabrication of small, compact, and efficient devices for optoelectronic and photonic applications.

  4. Power scaling of ultrafast mid-IR source enabled by high-power fiber laser technology

    International Nuclear Information System (INIS)

    Zhou, Gengji

    2017-11-01

    Ultrafast laser sources with high repetition-rate (>10 MHz) and tunable in the mid-infrared (IR) wavelength range of 7-18 μm hold promise for many important spectroscopy applications. Currently, these ultrafast mid- to longwavelength-IR sources can most easily be achieved via difference-frequency generation (DFG) between a pump beam and a signal beam. However, current ultrafast mid- to longwavelength-IR sources feature a low average power, which limits their applications. In this thesis, we propose and demonstrate a novel approach to power scaling of DFG-based ultrafast mid-IR laser sources. The essence of this novel approach is the generation of a high-energy signal beam. Both the pump beam and the signal beam are derived from a home-built Yb-fiber laser system that emits 165-fs pulses centered at 1035 nm with 30-MHz repetition rate and 14.5-W average power (corresponding to 483-nJ pulse energy). We employ fiber-optic self-phase modulation (SPM) to broaden the laser spectrum and generate isolated spectral lobes. Filtering the rightmost spectral lobe leads to femtosecond pulses with >10 nJ pulse energy. Tunable between 1.1-1.2 μm, this SPM-enabled ultrafast source exhibits ∝100 times higher pulse energy than can be obtained from Raman soliton sources in this wavelength range. We use this SPM-enabled source as the signal beam and part of the Yb-fiber laser output as the pump beam. By performing DFG in GaSe crystals, we demonstrate that power scaling of a DFG-based mid-IR source can be efficiently achieved by increasing the signal energy. The resulting mid-IR source is tunable from 7.4 μm to 16.8 μm. Up to 5.04-mW mid-IR pulses centered at 11 μm are achieved. The corresponding pulse energy is 167 pJ, representing nearly one order of magnitude improvement compared with other reported DFG-based mid-IR sources at this wavelength. Despite of low pulse energy, Raman soliton sources have become a popular choice as the signal source. We carry out a detailed study on

  5. Power scaling of ultrafast mid-IR source enabled by high-power fiber laser technology

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Gengji

    2017-11-15

    Ultrafast laser sources with high repetition-rate (>10 MHz) and tunable in the mid-infrared (IR) wavelength range of 7-18 μm hold promise for many important spectroscopy applications. Currently, these ultrafast mid- to longwavelength-IR sources can most easily be achieved via difference-frequency generation (DFG) between a pump beam and a signal beam. However, current ultrafast mid- to longwavelength-IR sources feature a low average power, which limits their applications. In this thesis, we propose and demonstrate a novel approach to power scaling of DFG-based ultrafast mid-IR laser sources. The essence of this novel approach is the generation of a high-energy signal beam. Both the pump beam and the signal beam are derived from a home-built Yb-fiber laser system that emits 165-fs pulses centered at 1035 nm with 30-MHz repetition rate and 14.5-W average power (corresponding to 483-nJ pulse energy). We employ fiber-optic self-phase modulation (SPM) to broaden the laser spectrum and generate isolated spectral lobes. Filtering the rightmost spectral lobe leads to femtosecond pulses with >10 nJ pulse energy. Tunable between 1.1-1.2 μm, this SPM-enabled ultrafast source exhibits ∝100 times higher pulse energy than can be obtained from Raman soliton sources in this wavelength range. We use this SPM-enabled source as the signal beam and part of the Yb-fiber laser output as the pump beam. By performing DFG in GaSe crystals, we demonstrate that power scaling of a DFG-based mid-IR source can be efficiently achieved by increasing the signal energy. The resulting mid-IR source is tunable from 7.4 μm to 16.8 μm. Up to 5.04-mW mid-IR pulses centered at 11 μm are achieved. The corresponding pulse energy is 167 pJ, representing nearly one order of magnitude improvement compared with other reported DFG-based mid-IR sources at this wavelength. Despite of low pulse energy, Raman soliton sources have become a popular choice as the signal source. We carry out a detailed study on

  6. Advanced Optical Processing of Microwave Signals

    Directory of Open Access Journals (Sweden)

    Miguel V. Andrés

    2005-06-01

    Full Text Available The authors present a review on the recent approaches proposed to implement transversal RF filters. Different tunable transversal filters consisting of wavelength tunable optical taps and those employing the tunability of dispersive devices are presented showing their high-performance characteristics. A comprehensive review of the fundamentals and a discussion on the main limitation of these structures are also included.

  7. Outstanding laser damage threshold in Li2MnGeS4 and tunable optical nonlinearity in diamond-like semiconductors.

    Science.gov (United States)

    Brant, Jacilynn A; Clark, Daniel J; Kim, Yong Soo; Jang, Joon I; Weiland, Ashley; Aitken, Jennifer A

    2015-03-16

    The new Li2MnGeS4 and Li2CoSnS4 compounds result from employing a rational and simple design strategy that guides the discovery of diamond-like semiconductors (DLSs) with wide regions of optical transparency, high laser damage threshold, and efficient second-order optical nonlinearity. Single-crystal X-ray diffraction was used to solve and refine the crystal structures of Li2MnGeS4 and Li2CoSnS4, which crystallize in the noncentrosymmetric space groups Pna21 and Pn, respectively. Synchrotron X-ray powder diffraction (SXRPD) was used to assess the phase purity, and diffuse reflectance UV-vis-NIR spectroscopy was used to estimate the bandgaps of Li2MnGeS4 (Eg = 3.069(3) eV) and Li2CoSnS4 (Eg = 2.421(3) eV). In comparison with Li2FeGeS4, Li2FeSnS4, and Li2CoSnS4 DLSs, Li2MnGeS4 exhibits the widest region of optical transparency (0.60-25 μm) and phase matchability (≥1.6 μm). All four of the DLSs exhibit second-harmonic generation and are compared with the benchmark NLO material, AgGaSe2. Most remarkably, Li2MnGeS4 does not undergo two- or three-photon absorption upon exposure to a fundamental Nd:YAG beam (λ = 1.064 μm) and exhibits a laser damage threshold > 16 GW/cm(2).

  8. Femtosecond all-optical parallel logic gates based on tunable saturable to reverse saturable absorption in graphene-oxide thin films

    International Nuclear Information System (INIS)

    Roy, Sukhdev; Yadav, Chandresh

    2013-01-01

    A detailed theoretical analysis of ultrafast transition from saturable absorption (SA) to reverse saturable absorption (RSA) has been presented in graphene-oxide thin films with femtosecond laser pulses at 800 nm. Increase in pulse intensity leads to switching from SA to RSA with increased contrast due to two-photon absorption induced excited-state absorption. Theoretical results are in good agreement with reported experimental results. Interestingly, it is also shown that increase in concentration results in RSA to SA transition. The switching has been optimized to design parallel all-optical femtosecond NOT, AND, OR, XOR, and the universal NAND and NOR logic gates

  9. Double lens device for tunable harmonic generation of laser beams in KBBF/RBBF crystals or other non-linear optic materials

    Science.gov (United States)

    Kaminski, Adam

    2017-08-22

    A method and apparatus to generate harmonically related laser wavelengths includes a pair of lenses at opposing faces of a non-linear optical material. The lenses are configured to promote incoming and outgoing beams to be normal to each outer lens surface over a range of acceptance angles of the incoming laser beam. This reduces reflection loss for higher efficiency operation. Additionally, the lenses allow a wider range of wavelengths for lasers for more universal application. Examples of the lenses include plano-cylindrical and plano-spherical form factors.

  10. Tunability of optofluidic distributed feedback dye lasers

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Kristensen, Anders

    2007-01-01

    We investigate the tunability of optofluidic distributed feedback (DFB) dye lasers. The lasers rely on light-confinement in a nano-structured polymer film where an array of nanofluidic channels constitutes a third order Bragg grating DFB laser resonator with a central phase-shift. The lasers...... are operated by filling the DFB laser resonator with a dye solution by capillary action and optical pumping with a frequency doubled Nd: YAG laser. The low reflection order of the DFB laser resonator yields low out-of-plane scattering losses as well as a large free spectral range (FSR), and low threshold...... fluences down to similar to 7 mu J/mm2 are observed. The large FSR facilitates wavelength tuning over the full gain spectrum of the chosen laser dye and we demonstrate 45 nm tunability using a single laser dye by changing the grating period and dye solution refractive index. The lasers are straight...

  11. Tunable optical properties of ZnCdTe2-xSex(x =0.625) chalcopyrite for photovoltaics; a mBJLDA approach

    Science.gov (United States)

    Kashyap, Manish K.; Paudyal, D.; Harmon, B. N.

    In the present study, we have performed ab-initio simulations of sp-element defect in ZnCdTe2-xSex (x =0.625) chalcopyrite to check the tuning of band gap as compared to the pristine case. The exchange and correlation (XC) effects are taken into account by an orbital independent modified Becke-Johnson (mBJ) potential as coupled with Local Density Approximation (LDA) for these calculations. The calculated energy band structures show a direct band gap at the point in the brillouin zone for the pristine as well as the defected case and the band gap decreases with inclusion of sp-disorder. The imaginary dielectric function predicts the optical band gap of pristine ZnCdTe2 very close to the experimental value and the results are in reasonable agreement without applying any scissor operator. With inclusion of sp-element defect, the optical spectra is tuned to optimal region, suitable for photovoltaics. It is apparent that mBJ functional is well suited for calculating electronic structure of pristine as well as defected ZnCdTe2chalcopyrite. MKK acknowledges financial support from UGC, India in the form of RAMAN Post-doctoral fellowship. This work at Ames Laboratory was supported by the DOE, Office of Basic Energy Sciences, Materials Sciences Division under contract No. DE-AC02-07CH11358.

  12. Lidar/DIAL detection of acetone at 3.3 μm by a tunable OPO laser system

    Science.gov (United States)

    Puiu, A.; Fiorani, L.; Rosa, O.; Borelli, R.; Pistilli, M.; Palucci, A.

    2014-08-01

    In this paper we report, for the first time to our knowledge, on lidar/DIAL detection of acetone vapors at 3.3 μm by means of an optical parametric tunable laser system. After a preliminary spectroscopic study in an absorption cell, the feasibility of a differential absorption (DIAL) lidar for the detection of acetone vapors has been investigated in the laboratory, simulating the experimental conditions of a field campaign. Having in mind measurements in a real scenario, a study of possible atmospheric intereferents has been performed, looking for all known compounds that share acetone IR absorption in the spectral band selected for its detection. Possible interfering species from urban and industrial atmospheres were investigated and limits of acetone detection in both environments were identified. This study confirmed that a lidar system can detect a low concentration of acetone at considerable distances.

  13. Tunable conductivity in mesoporous germanium

    Science.gov (United States)

    Beattie, Meghan N.; Bioud, Youcef A.; Hobson, David G.; Boucherif, Abderraouf; Valdivia, Christopher E.; Drouin, Dominique; Arès, Richard; Hinzer, Karin

    2018-05-01

    Germanium-based nanostructures have attracted increasing attention due to favourable electrical and optical properties, which are tunable on the nanoscale. High densities of germanium nanocrystals are synthesized via electrochemical etching, making porous germanium an appealing nanostructured material for a variety of applications. In this work, we have demonstrated highly tunable electrical conductivity in mesoporous germanium layers by conducting a systematic study varying crystallite size using thermal annealing, with experimental conductivities ranging from 0.6 to 33 (×10‑3) Ω‑1 cm‑1. The conductivity of as-prepared mesoporous germanium with 70% porosity and crystallite size between 4 and 10 nm is shown to be ∼0.9 × 10‑3 Ω‑1 cm‑1, 5 orders of magnitude smaller than that of bulk p-type germanium. Thermal annealing for 10 min at 400 °C further reduced the conductivity; however, annealing at 450 °C caused a morphological transformation from columnar crystallites to interconnecting granular crystallites and an increase in conductivity by two orders of magnitude relative to as-prepared mesoporous germanium caused by reduced influence of surface states. We developed an electrostatic model relating the carrier concentration and mobility of p-type mesoporous germanium to the nanoscale morphology. Correlation within an order of magnitude was found between modelled and experimental conductivities, limited by variation in sample uniformity and uncertainty in void size and fraction after annealing. Furthermore, theoretical results suggest that mesoporous germanium conductivity could be tuned over four orders of magnitude, leading to optimized hybrid devices.

  14. Optically pumped terahertz sources

    Institute of Scientific and Technical Information of China (English)

    ZHONG Kai; SHI Wei; XU DeGang; LIU PengXiang; WANG YuYe; MEI JiaLin; YAN Chao; FU ShiJie; YAO JianQuan

    2017-01-01

    High-power terahertz (THz) generation in the frequency range of0.1-10 THz has been a fast-developing research area ever since the beginning of the THz boom two decades ago,enabling new technological breakthroughs in spectroscopy,communication,imaging,etc.By using optical (laser) pumping methods with near-or mid-infrared (IR) lasers,flexible and practical THz sources covering the whole THz range can be realized to overcome the shortage of electronic THz sources and now they are playing important roles in THz science and technology.This paper overviews various optically pumped THz sources,including femtosecond laser based ultrafast broadband THz generation,monochromatic widely tunable THz generation,single-mode on-chip THz source from photomixing,and the traditional powerful THz gas lasers.Full descriptions from basic principles to the latest progress are presented and their advantages and disadvantages are discussed as well.It is expected that this review gives a comprehensive reference to researchers in this area and additionally helps newcomers to quickly gain understanding of optically pumped THz sources.

  15. Spin-polarized 3He nuclear targets and metastable 4He atoms by optical pumping with a tunable, Nd:YAP laser

    International Nuclear Information System (INIS)

    Bohler, C.L.; Schearer, L.D.; Leduc, M.; Nacher, P.J.; Zachorowski, L.; Milner, R.G.; McKeown, R.D.; Woodward, C.E.

    1988-01-01

    Several Nd:YAP lasers were constructed which could be broadly tuned in the 1083-nm region which includes the helium 2 3 S-2 3 P transition, using a Lyot filter and thin, uncoated etalons within the laser cavity. 1 W of power could be extracted at 1083 nm through a 1% transmitting output coupler. This laser beam was used to optically pump metastable 4 He and 3 He 2 3 S helium atoms in a weak discharge cell, spin polarizing the metastable ensemble. In a 3 He cell the polarization is transferred to the nuclear spin system. A 3 He target cell at 0.3 Torr was polarized to 52% in a few minutes. We describe the application of this system to the design of polarized targets for experiments in nuclear physics

  16. Atmospheric boundary layer CO2 remote sensing with a direct detection LIDAR instrument based on a widely tunable optical parametric source.

    Science.gov (United States)

    Cadiou, Erwan; Mammez, Dominique; Dherbecourt, Jean-Baptiste; Gorju, Guillaume; Pelon, Jacques; Melkonian, Jean-Michel; Godard, Antoine; Raybaut, Myriam

    2017-10-15

    We report on the capability of a direct detection differential absorption lidar (DIAL) for range resolved and integrated path (IPDIAL) remote sensing of CO 2 in the atmospheric boundary layer (ABL). The laser source is an amplified nested cavity optical parametric oscillator (NesCOPO) emitting approximately 8 mJ at the two measurement wavelengths selected near 2050 nm. Direct detection atmospheric measurements are taken from the ground using a 30 Hz frequency switching between emitted wavelengths. Results show that comparable precision measurements are achieved in DIAL and IPDIAL modes (not better than a few ppm) on high SNR targets such as near range ABL aerosol and clouds, respectively. Instrumental limitations are analyzed and degradation due to cloud scattering variability is discussed to explain observed DIAL and IPDIAL limitations.

  17. Fluidic optics

    Science.gov (United States)

    Whitesides, George M.; Tang, Sindy K. Y.

    2006-09-01

    Fluidic optics is a new class of optical system with real-time tunability and reconfigurability enabled by the introduction of fluidic components into the optical path. We describe the design, fabrication, operation of a number of fluidic optical systems, and focus on three devices, liquid-core/liquid-cladding (L2) waveguides, microfluidic dye lasers, and diffraction gratings based on flowing, crystalline lattices of bubbles, to demonstrate the integration of microfluidics and optics. We fabricate these devices in poly(dimethylsiloxane) (PDMS) with soft-lithographic techniques. They are simple to construct, and readily integrable with microanalytical or lab-on-a-chip systems.

  18. MEMS Tunable nanostructured photodetector

    DEFF Research Database (Denmark)

    Learkthanakhachon, Supannee

    This thesis was prepared at the department of Photonics Engineering, the Technical University of Denmark in fulfilment of the requirements for acquiring a Philosophiae doctor (Ph.D.) in Photonics Engineering. The thesis deals with the design and fabrication of tunable resonant-cavity-enhanced pho......) structure. Results from the fabricated devices are reported along with an investigation of the design parameters which influence the performance deviation from the design....

  19. An ultra-wideband tunable multi-wavelength Brillouin fibre laser based on a semiconductor optical amplifier and dispersion compensating fibre in a linear cavity configuration

    International Nuclear Information System (INIS)

    Zulkifli, M Z; Ahmad, H; Hassan, N A; Jemangin, M H; Harun, S W

    2011-01-01

    A multi-wavelength Brillouin fibre laser (MBFL) with an ultra-wideband tuning range from 1420 nm to 1620 nm is demonstrated. The MBFL uses an ultra-wideband semiconductor optical amplifier (SOA) and a dispersion compensating fibre (DCF) as the linear gain medium and nonlinear gain medium, respectively. The proposed MBFL has a wide tuning range covering the short (S-), conventional (C-) and long (L-) bands with a wavelength spacing of 0.08 nm, making it highly suitable for DWDM system applications. The output power of the observed Brillouin Stokes ranges approximately from -5.94 dBm to -0.41 dBm for the S-band, from -4.34 dBm to 0.02 dBm for the C-band and from -2.19 dBm to 0.39 dBm for the L-band. The spacing between each adjacent wavelengths of all the three bands is about 0.08 nm, which is approximately 10.7 GHz for the frequency domain. (lasers)

  20. Facile synthesis of CuSe nanoparticles and high-quality single-crystal two-dimensional hexagonal nanoplatelets with tunable near-infrared optical absorption

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yimin [State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Korolkov, Ilia [Laboratory of Glasses and Ceramics, Institute of Chemistry, CNRS-Université de Rennes I, Campus de Beaulieu, 35042 Rennes Cedex (France); Qiao, Xvsheng [State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Zhang, Xianghua [Laboratory of Glasses and Ceramics, Institute of Chemistry, CNRS-Université de Rennes I, Campus de Beaulieu, 35042 Rennes Cedex (France); Wan, Jun; Fan, Xianping [State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2016-06-15

    A rapid injection approach is used to synthesize the copper selenide nanoparticles and two-dimensional single crystal nanoplates. This technique excludes the use of toxic or expensive materials, increasing the availability of two-dimensional binary chalcogenide semiconductors. The structure of the nanocrystals has been studied and the possible formation mechanism of the nanoplates has been proposed. The optical absorption showed that the nanoplates demonstrated wide and tuneable absorption band in the visible and near infrared region. These nanoplates could be interesting for converting solar energy and for nanophotonic devices operating in the near infrared. - Graphical abstract: TEM images of the copper selenides nanoparticles and nanoplates synthesized at 180 °C for 0 min, 10 min, 60 min. And the growth mechanism of the copper selenide nanoplates via the “oriented attachment”. Display Omitted - Highlights: • CuSe nanoparticles and nanoplates are synthesized by a rapid injection approach. • CuSe band gap can be widely tuned simply by modifying the synthesized time. • Al{sup 3+} ions have a significant impact on the growth rate of the nanoplates. • Growth mechanism of the CuSe nanoplates is based on the “oriented attachment”.

  1. Liquid crystal parameter analysis for tunable photonic bandgap fiber devices

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Wei, Lei

    2010-01-01

    We investigate the tunability of splay-aligned liquid crystals for the use in solid core photonic crystal fibers. Finite element simulations are used to obtain the alignment of the liquid crystals subject to an external electric field. By means of the liquid crystal director field the optical...

  2. One-pot synthesis of Zn{sub x}Cd{sub 1-x}S nanocrystals with tunable optical properties from molecular precursors

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhigang, E-mail: zgchen@dhu.edu.c [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Tian Qiwei; Song Yuelin [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Yang Jianmao [Research Center for Analysis and Measurement, Donghua University, Shanghai 201620 (China); Hu Junqing, E-mail: hu.junqing@dhu.edu.c [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China)

    2010-09-17

    We have reported a non-injection one-pot synthesis of the alloyed Zn{sub x}Cd{sub 1-x}S semiconductor nanocrystals (SNCs) with controlled shapes and compositions. This non-injection approach involves heating two molecular precursors (cadmium ethylxanthate and zinc ethylxanthate) as metal and S sources in organic solvents at 320 {sup o}C for 30 min, which results in the thermal decompositions of the molecular precursors to produce Zn{sub x}Cd{sub 1-x}S. The effects of solvents and compositions on the shapes and structures of Zn{sub x}Cd{sub 1-x}S SNCs have been investigated. The mixture solvent containing oleic acid, paraffin oil and oleylamine (such as a volume ratio: 1/2/1) results in the preparation of uniform Zn{sub x}Cd{sub 1-x}S nanoparticles with diameters of 7-13 nm, while pure oleylamine or the mixture of oleylamine and paraffin oil as the solvent leads to the formation of uniform Zn{sub x}Cd{sub 1-x}S nanorods. Monodisperse wurtzite Zn{sub x}Cd{sub 1-x}S nanorods with different compositions have been prepared in pure oleylamine, and no obvious effects of the compositions on their shapes are found. Their alloying nature is consistently confirmed by the results of high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and optical measurements. These alloyed Zn{sub x}Cd{sub 1-x}S nanorods exhibit composition-dependent absorption and emission properties, and therefore they can be promising candidates as emitting materials.

  3. LO-TO splittings, effective charges and interactions in electro-optic meta-nitroaniline crystal as studied by polarized IR reflection and transmission spectra

    Science.gov (United States)

    Szostak, M. M.; Le Calvé, N.; Romain, F.; Pasquier, B.

    1994-10-01

    The polarized IR reflection spectra of the meta-nitroaniline ( m-NA) single crystal along the a, b and c crystallographic axes as well as the b and c polarized transmission spectra have been measured in the 100-400 cm -1 region. The LO-TO splitting values have been calculated from the reflection spectra by fitting them with the four parameter dielectric function. The dipole moment derivatives, relevant to dynamic effective charges, of the vibrations have also been calculated and used to check the applicability of the oriented gas model (OGM) to reflection spectra. The discrepancies from the OGM have been discussed in terms of vibronic couplings, weak hydrogen bondings (HB) and intramolecular charge transfer.

  4. Magnetic nanoparticles for tunable microwave metamaterials

    KAUST Repository

    Noginova, Natalia; Williams, Quincy Leon; Dallas, Panagiotis; Giannelis, Emmanuel P.

    2012-01-01

    Commonly, metamaterials are electrically engineered systems with optimized spatial arrangement of subwavelength sized metal and dielectric components. We explore alternative methods based on use of magnetic inclusions, such as magnetic nanoparticles, which can allow permeability of a composite to be tuned from negative to positive at the range of magnetic resonance. To better understand effects of particle size and magnetization dynamics, we performed electron magnetic resonance study on several varieties of magnetic nanoparticles and determined potential of nanoparticle use as building blocks for tunable microwave metamaterials. © (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  5. Magnetic nanoparticles for tunable microwave metamaterials

    KAUST Repository

    Noginova, Natalia

    2012-09-24

    Commonly, metamaterials are electrically engineered systems with optimized spatial arrangement of subwavelength sized metal and dielectric components. We explore alternative methods based on use of magnetic inclusions, such as magnetic nanoparticles, which can allow permeability of a composite to be tuned from negative to positive at the range of magnetic resonance. To better understand effects of particle size and magnetization dynamics, we performed electron magnetic resonance study on several varieties of magnetic nanoparticles and determined potential of nanoparticle use as building blocks for tunable microwave metamaterials. © (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  6. Effect of H{sup +} implantation on the optical properties of semi-insulating GaAs crystals in the IR spectral region

    Energy Technology Data Exchange (ETDEWEB)

    Klyui, N. I.; Lozinskii, V. B., E-mail: lvb@isp.kiev.ua [Jilin University, College of Physics (China); Liptuga, A. I.; Dikusha, V. N. [National Academy of Sciences of Ukraine, Lashkaryov Institute of Semiconductor Physics (Ukraine); Oksanych, A. P.; Kogdas’, M. G.; Perekhrest, A. L.; Pritchin, S. E. [Kremenchug National University (Ukraine)

    2017-03-15

    The optical properties of semi-insulating GaAs crystals subjected to multienergy hydrogen-ion implantation and treatment in a high-frequency electromagnetic field are studied in the infrared spectral region. It is established that such combined treatment provides a means for substantially increasing the transmittance of GaAs crystals to values characteristic of crystals of high optical quality. On the basis of analysis of the infrared transmittance and reflectance data, Raman spectroscopy data, and atomic-force microscopy data on the surface morphology of the crystals, a physical model is proposed to interpret the effects experimentally observed in the crystals. The model takes into account the interaction of radiation defects with the initial structural defects in the crystals as well as the effect of compensation of defect centers by hydrogen during high-frequency treatment.

  7. Demonstration of a near-IR line-referenced electro-optical laser frequency comb for precision radial velocity measurements in astronomy.

    Science.gov (United States)

    Yi, X; Vahala, K; Li, J; Diddams, S; Ycas, G; Plavchan, P; Leifer, S; Sandhu, J; Vasisht, G; Chen, P; Gao, P; Gagne, J; Furlan, E; Bottom, M; Martin, E C; Fitzgerald, M P; Doppmann, G; Beichman, C

    2016-01-27

    An important technique for discovering and characterizing planets beyond our solar system relies upon measurement of weak Doppler shifts in the spectra of host stars induced by the influence of orbiting planets. A recent advance has been the introduction of optical frequency combs as frequency references. Frequency combs produce a series of equally spaced reference frequencies and they offer extreme accuracy and spectral grasp that can potentially revolutionize exoplanet detection. Here we demonstrate a laser frequency comb using an alternate comb generation method based on electro-optical modulation, with the comb centre wavelength stabilized to a molecular or atomic reference. In contrast to mode-locked combs, the line spacing is readily resolvable using typical astronomical grating spectrographs. Built using commercial off-the-shelf components, the instrument is relatively simple and reliable. Proof of concept experiments operated at near-infrared wavelengths were carried out at the NASA Infrared Telescope Facility and the Keck-II telescope.

  8. Effect of H+ implantation on the optical properties of semi-insulating GaAs crystals in the IR spectral region

    International Nuclear Information System (INIS)

    Klyui, N. I.; Lozinskii, V. B.; Liptuga, A. I.; Dikusha, V. N.; Oksanych, A. P.; Kogdas’, M. G.; Perekhrest, A. L.; Pritchin, S. E.

    2017-01-01

    The optical properties of semi-insulating GaAs crystals subjected to multienergy hydrogen-ion implantation and treatment in a high-frequency electromagnetic field are studied in the infrared spectral region. It is established that such combined treatment provides a means for substantially increasing the transmittance of GaAs crystals to values characteristic of crystals of high optical quality. On the basis of analysis of the infrared transmittance and reflectance data, Raman spectroscopy data, and atomic-force microscopy data on the surface morphology of the crystals, a physical model is proposed to interpret the effects experimentally observed in the crystals. The model takes into account the interaction of radiation defects with the initial structural defects in the crystals as well as the effect of compensation of defect centers by hydrogen during high-frequency treatment.

  9. High-power dual-wavelength external-Cavity diode laser based on tapered amplifier with tunable terahertz frequency difference

    DEFF Research Database (Denmark)

    Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

    2011-01-01

    Tunable dual-wavelength operation of a diode laser system based on a tapered diode amplifier with double-Littrow external-cavity feedback is demonstrated around 800nm. The two wavelengths can be tuned individually, and the frequency difference of the two wavelengths is tunable from 0.5 to 5:0 THz......, this is the highest output power from a dual-wavelength diode laser system operating with tunable terahertz frequency difference. © 2011 Optical Society of America....

  10. In situ growth of hollow gold-silver nanoshells within porous silica offers tunable plasmonic extinctions and enhanced colloidal stability.

    Science.gov (United States)

    Li, Chien-Hung; Jamison, Andrew C; Rittikulsittichai, Supparesk; Lee, Tai-Chou; Lee, T Randall

    2014-11-26

    Porous silica-coated hollow gold-silver nanoshells were successfully synthesized utilizing a procedure where the porous silica shell was produced prior to the transformation of the metallic core, providing enhanced control over the structure/composition of the bimetallic hollow core. By varying the reaction time and the precise amount of gold salt solution added to a porous silica-coated silver-core template solution, composite nanoparticles were tailored to reveal a readily tunable surface plasmon resonance that could be centered across the visible and near-IR spectral regions (∼445-800 nm). Characterization by X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy revealed that the synthetic methodology afforded particles having uniform composition, size, and shape. The optical properties were evaluated by absorption/extinction spectroscopy. The stability of colloidal solutions of our composite nanoparticles as a function of pH was also investigated, revealing that the nanoshells remain intact over a wide range of conditions (i.e., pH 2-10). The facile tunability, enhanced stability, and relatively small diameter of these composite particles (∼110 nm) makes them promising candidates for use in tumor ablation or as photothermal drug-delivery agents.

  11. Optical spectra of Zn{sub 1-x}Be{sub x}Te mixed crystals determined by IR-VIS-UV ellipsometry and photoluminescence measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wronkowska, A.A., E-mail: aleksandra.wronkowska@utp.edu.p [Institute of Mathematics and Physics, University of Technology and Life Sciences, S. Kaliskiego 7, PL-85796 Bydgoszcz (Poland); Arwin, H. [Department of Physics, Chemistry and Biology, Linkoeping University, SE-58183 Linkoeping (Sweden); Firszt, F.; Legowski, S. [Institute of Physics, Nicholas Copernicus University, Grudziadzka 5, PL-87100 Torun (Poland); Wronkowski, A.; Skowronski, L. [Institute of Mathematics and Physics, University of Technology and Life Sciences, S. Kaliskiego 7, PL-85796 Bydgoszcz (Poland)

    2011-02-28

    Spectroscopic ellipsometry in the photon energy range from 0.04 eV to 6.50 eV is used for investigation of the optical response of Zn{sub 1-x}Be{sub x}Te crystals grown by a high-pressure Bridgman method in the composition range x {<=} 0.12. Infrared spectra display absorption bands centred between 411 cm{sup -1} and 420 cm{sup -1} associated with BeTe-type optical phonon modes. The positions of the transverse-optical and longitudinal-optical phonon modes have been found by modelling the line shape of the complex dielectric functions, {epsilon}-tilde and Im(-{epsilon}-tilde{sup -1}), using a classical damped Lorentzian oscillator approach. Ellipsometric measurements in the VIS-UV range allow determination of the fundamental energy-gap (E{sub 0}) and the higher threshold energies (E{sub 1}, E{sub 1} + {Delta}{sub 1}, E{sub 2}) originating from the band edge and spin-orbit splitting critical points. We have found that the Be content x = 0.12 causes an increase of the fundamental energy gap about 0.15 eV at room temperature when compared to the E{sub 0} = 2.23 eV of ZnTe crystal at the same temperature. Photoluminescence spectra were measured in the temperature range from 30 K to room temperature. Luminescence at temperature T > 200 K is very weak. The peak positions of the exciton emission lines agree well with the E{sub 0} band-gaps derived from ellipsometric data if corrected for their temperature dependence.

  12. Broad band tunable dye laser development

    International Nuclear Information System (INIS)

    Lee, Jong Min; Kim, Jung Bog; Kim, Sung Ho; Go, Do Kyung; Lim, Chang Hwan; Rho, Si Pyo; Song, Kyu Seok; Lee, Byung Cheol; Rhi, Jong Hoon; Han, Jae Min; Cha, Hyung Ki; Cha, Byung Hun; Jeong, Do Yung; Han, Jae Min; Jung, Yeu Chang; Im, Ho; Yoo, Choon Sun; Jung, Byung Ik; Seok, Gum Sook

    1992-12-01

    The technical goal and objectives are the development of a tunable laser which can be tuned from UV to near IR and commercialization for uses in various fields. Two kinds of resonators are developed. User can select one resonator and change into the other without changing other parts. GIM type has a linewidth of 5GHz which is able to be used usually, and SLM type is very narrow linewidth of less than 1GHz. Each system can have one or two amplifiers depending on output power or cost. High stability and safety, cost-down, and modules into about 30 components have been tried. We hope that this laser can help developments in researches of university, industry, and institute. (Author)

  13. Tunable graphene antennas for selective enhancement of THz-emission

    KAUST Repository

    Filter, Robert; Farhat, Mohamed; Steglich, Mathias; Alaee, Rasoul; Rockstuhl, Carsten; Lederer, Falk L.

    2013-01-01

    In this paper, we will introduce THz graphene antennas that strongly enhance the emission rate of quantum systems at specific frequencies. The tunability of these antennas can be used to selectively enhance individual spectral features. We will show as an example that any weak transition in the spectrum of coronene can become the dominant contribution. This selective and tunable enhancement establishes a new class of graphene-based THz devices, which will find applications in sensors, novel light sources, spectroscopy, and quantum communication devices. © 2013 Optical Society of America.

  14. 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....

  15. Tunable resistance coatings

    Science.gov (United States)

    Elam, Jeffrey W.; Mane, Anil U.

    2015-08-11

    A method and article of manufacture of intermixed tunable resistance composite materials containing at least one of W:Al.sub.2O.sub.3, Mo:Al.sub.2O.sub.3 or M:Al.sub.2O.sub.3 where M is a conducting compound containing either W or Mo. A conducting material and an insulating material are deposited by such methods as ALD or CVD to construct composites with intermixed materials which do not have structure or properties like their bulk counterparts.

  16. Tunable Nitride Josephson Junctions.

    Energy Technology Data Exchange (ETDEWEB)

    Missert, Nancy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Henry, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lewis, Rupert M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wolfley, Steven L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunke, Lyle Brent [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wolak, Matthaeus [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    We have developed an ambient temperature, SiO2/Si wafer - scale process for Josephson junctions based on Nb electrodes and Ta x N barriers with tunable electronic properties. The films are fabricated by magnetron sputtering. The electronic properties of the TaxN barriers are controlled by adjusting the nitrogen flow during sputtering. This technology offers a scalable alternative to the more traditional junctions based on AlOx barriers for low - power, high - performance computing.

  17. Structural, spectroscopic (FT-IR, NMR, UV-visible), nonlinear optical (NLO), cytotoxic and molecular docking studies of 4-nitro-isonitrosoacetophenone (ninapH) by DFT method

    Science.gov (United States)

    Kucuk, Ilhan; Kaya, Yunus; Kaya, A. Asli

    2017-07-01

    (4-Nitro-phenyl)-oxo-acetaldehyde oxime (ninapH) is a type of oxime, which has a oxime and α-carbonyl groups. This molecule has been synthesized from literature procedure. The structural properties and conformational behaviors were examined using the density functional theory (DFT) with the B3LYP method combined with the 6-311++G(d,p) basis set. As a result of the conformational studies, the most stable conformer was determined, and then this molecule was optimized with the same basis set. Comprehensive theoretical and experimental structural studies on the molecule have been carried out by FT-IR, NMR and UV-vis spectrometry. The calculated HOMO and LUMO energies show that charge transfer within the molecule. The first order hyperpolarizability and molecular electrostatic potential (MEP) were also performed. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the ninapH have been calculated at different temperatures, 100-1000 K. In addition, the molecular docking studies have been performed with DNA and protein structures (downloaded from Protein Data Bank).

  18. Optics

    CERN Document Server

    Mathieu, Jean Paul

    1975-01-01

    Optics, Parts 1 and 2 covers electromagnetic optics and quantum optics. The first part of the book examines the various of the important properties common to all electromagnetic radiation. This part also studies electromagnetic waves; electromagnetic optics of transparent isotropic and anisotropic media; diffraction; and two-wave and multi-wave interference. The polarization states of light, the velocity of light, and the special theory of relativity are also examined in this part. The second part is devoted to quantum optics, specifically discussing the classical molecular theory of optical p

  19. Tunable lasers for waste management photochemistry applications

    International Nuclear Information System (INIS)

    Finch, F.T.

    1978-09-01

    A review of lasers with potential photochemical applications in waste management indicates that dye lasers, as a class, can provide tunable laser output through the visible and near-uv regions of the spectrum of most interest to photochemistry. Many variables can affect the performance of a specific dye laser, and the interactions of these variables, at the current state of the art, are complex. The recent literature on dye-laser characteristics has been reviewed and summarized, with emphasis on those parameters that most likely will affect the scaling of dye lasers in photochemical applications. Current costs are reviewed and correlated with output power. A new class of efficient uv lasers that appear to be scalable in both energy output and pulse rate, based on rare-gas halide excimers and similar molecules, is certain to find major applications in photochemistry. Because the most important developments are too recent to be adequately described in the literature or are the likely outcome of current experiments, the basic physics underlying the class of excimer lasers is described. Specific cost data are unavailable, but these new gas lasers should reflect costs similar to those of existing gas lasers, in particular, the pulsed CO 2 lasers. To complete the survey of tunable-laser characteristics, the technical characteristics of the various classes of lasers in the ir are summarized. Important developments in ir laser technology are being accelerated by isotope-separation research, but, initially at least, this portion of the spectrum is least likely to receive emphasis in waste-management-oriented photochemistry

  20. Efficient Long Wave IR Laser from Ho:YAG 2 {mu}m Pumped ZnGeP{sub 2} Optical Parametric Oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Li-Gang,; Bao-Quan, Yao; Xiao-Ming, Duan; Guo-Li, Zhu; Yue-Zhu, Wang; You-Lun, Ju [National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2010-01-15

    An efficient high power long wave infrared laser based on ZnGeP{sub 2} optical parametric oscillator pumped by a 2.09 {mu}m Tm:YLF/Ho:YAG laser at 10KHz pulse repetition rate is reported. The pump to idler conversion efficiency is 8% at 15.6 W Ho pump power level and a quantum efficiency of 31 % when the 1'idler wavelength is tuned at 8.08 {mu}m. The wavelength tuning range from 8-9.1 {mu}m is also achieved by rotating the ZGP crystal. (fundamental areas of phenomenology(including applications))

  1. Tunable radio-frequency photonic filter based on an actively mode-locked fiber laser.

    Science.gov (United States)

    Ortigosa-Blanch, A; Mora, J; Capmany, J; Ortega, B; Pastor, D

    2006-03-15

    We propose the use of an actively mode-locked fiber laser as a multitap optical source for a microwave photonic filter. The fiber laser provides multiple optical taps with an optical frequency separation equal to the external driving radio-frequency signal of the laser that governs its repetition rate. All the optical taps show equal polarization and an overall Gaussian apodization, which reduces the sidelobes. We demonstrate continuous tunability of the filter by changing the external driving radio-frequency signal of the laser, which shows good fine tunability in the operating range of the laser from 5 to 10 GHz.

  2. Optical filter based on Fabry-Perot structure using a suspension of goethite nanoparticles as electro-optic material

    Science.gov (United States)

    Abbas, Samir; Dupont, Laurent; Dozov, Ivan; Davidson, Patrick; Chanéac, Corinne

    2018-02-01

    We have investigated the feasibility of optical tunable filters based on a Fabry-Perot etalon that uses a suspension of goethite (α-FeOOH) nanorods as electro-optic material for application in optical telecommunications in the near IR range. These synthetic nanoparticles have a high optical anisotropy that give rise to a very strong Kerr effect in their colloidal suspensions. Currently, these particles are dispersed in aqueous solvent, with pH2 to ensure the colloidal electrostatic stability. However, the high conductivity of these suspensions requires using high-frequency electric fields (f > 1 MHz), which brings about a high power consumption of the driver. To decrease the field frequency, we have changed the solvent to ethylene glycol which has a lower electrical conductivity than the aqueous solvent. We have built a Fabry-Perot cell, filled with this colloidal suspension in the isotropic phase, and showed that a phase shift of 14 nm can be obtained in a field of 3V/μm. Therefore, the device can operate as a tunable filter. A key advantage of this filter is that it is, by principle, completely insensitive to the polarization of the input light. However, several technological issues still need to be solved, such as ionic contamination of the suspension from the blocking layers, and dielectrophoretic and thermal effects.

  3. Characterization of prepared In2O3 thin films: The FT-IR, FT-Raman, UV-Visible investigation and optical analysis.

    Science.gov (United States)

    Panneerdoss, I Joseph; Jeyakumar, S Johnson; Ramalingam, S; Jothibas, M

    2015-08-05

    In this original work, the Indium oxide (In2O3) thin film is deposited cleanly on microscope glass substrate at different temperatures by spray pyrolysis technique. The physical properties of the films are characterized by XRD, SEM, AFM and AFM measurements. The spectroscopic investigation has been carried out on the results of FT-IR, FT-Raman and UV-Visible. XRD analysis exposed that the structural transformation of films from stoichiometric to non-stoichiometric orientation of the plane vice versa and also found that, the film is polycrystalline in nature having cubic crystal structure with a preferred grain orientation along (222) plane. SEM and AFM studies revealed that, the film with 0.1M at 500°C has spherical grains with uniform dimension. The complete vibrational analysis has been carried out and the optimized parameters are calculated using HF and DFT (CAM-B3LYP, B3LYP and B3PW91) methods with 3-21G(d,p) basis set. Furthermore, NMR chemical shifts are calculated by using the gauge independent atomic orbital (GIAO) technique. The molecular electronic properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, molecular electrostatic potential energy (MEP) analysis and Polarizability first order hyperpolarizability calculations are performed by time dependent DFT (TD-DFT) approach. The energy excitation on electronic structure is investigated and the assignment of the absorption bands in the electronic spectra of steady compound is discussed. The calculated HOMO and LUMO energies showed the enhancement of energy gap by the addition of substitutions with the base molecule. The thermodynamic properties (heat capacity, entropy, and enthalpy) at different temperatures are calculated and interpreted in gas phase. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  4. Tunable Topological Phononic Crystals

    KAUST Repository

    Chen, Zeguo; Wu, Ying

    2016-01-01

    Topological insulators first observed in electronic systems have inspired many analogues in photonic and phononic crystals in which remarkable one-way propagation edge states are supported by topologically nontrivial band gaps. Such band gaps can be achieved by breaking the time-reversal symmetry to lift the degeneracy associated with Dirac cones at the corners of the Brillouin zone. Here, we report on our construction of a phononic crystal exhibiting a Dirac-like cone in the Brillouin zone center. We demonstrate that simultaneously breaking the time-reversal symmetry and altering the geometric size of the unit cell result in a topological transition that we verify by the Chern number calculation and edge-mode analysis. We develop a complete model based on the tight binding to uncover the physical mechanisms of the topological transition. Both the model and numerical simulations show that the topology of the band gap is tunable by varying both the velocity field and the geometric size; such tunability may dramatically enrich the design and use of acoustic topological insulators.

  5. Tunable Topological Phononic Crystals

    KAUST Repository

    Chen, Zeguo

    2016-05-27

    Topological insulators first observed in electronic systems have inspired many analogues in photonic and phononic crystals in which remarkable one-way propagation edge states are supported by topologically nontrivial band gaps. Such band gaps can be achieved by breaking the time-reversal symmetry to lift the degeneracy associated with Dirac cones at the corners of the Brillouin zone. Here, we report on our construction of a phononic crystal exhibiting a Dirac-like cone in the Brillouin zone center. We demonstrate that simultaneously breaking the time-reversal symmetry and altering the geometric size of the unit cell result in a topological transition that we verify by the Chern number calculation and edge-mode analysis. We develop a complete model based on the tight binding to uncover the physical mechanisms of the topological transition. Both the model and numerical simulations show that the topology of the band gap is tunable by varying both the velocity field and the geometric size; such tunability may dramatically enrich the design and use of acoustic topological insulators.

  6. Electrothermally Tunable Arch Resonator

    KAUST Repository

    Hajjaj, Amal Z.

    2017-03-18

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of electrothermally actuated microelectromechanical arch beams. The beams are made of silicon and are intentionally fabricated with some curvature as in-plane shallow arches. An electrothermal voltage is applied between the anchors of the beam generating a current that controls the axial stress caused by thermal expansion. When the electrothermal voltage increases, the compressive stress increases inside the arch beam. This leads to an increase in its curvature, thereby increasing its resonance frequencies. We show here that the first resonance frequency can increase monotonically up to twice its initial value. We show also that after some electrothermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches as wide-range tunable resonators. Analytical results based on the nonlinear Euler Bernoulli beam theory are generated and compared with the experimental data and the results of a multi-physics finite-element model. A good agreement is found among all the results. [2016-0291

  7. Optical characterization, 1.5 μm emission and IR-to-visible energy upconversion in Er3+-doped fluorotellurite glasses

    International Nuclear Information System (INIS)

    Rodriguez-Mendoza, U.R.; Lalla, E.A.; Caceres, J.M.; Rivera-Lopez, F.; Leon-Luis, S.F.; Lavin, V.

    2011-01-01

    The optical properties of Er 3+ ions in a novel glass based on TeO 2 -PbF 2 -AlF 3 oxyfluoride tellurites have been investigated using steady-state and time-resolved spectroscopies as a function of the rare-earth doping concentration. Basic optical characterizations have been performed measuring and calculating the absorption and emission spectra and the cross-sections, the Judd-Ofelt intensity parameters, the radiative probabilities and the fluorescence decays and lifetimes. Special attention has been devoted to the broad 4 I 13/2 → 4 I 15/2 emission transition at around 1.53 μm since, with a wide broadening of around 70 nm and a relative long lifetime of around 3 ms compared to others glass hosts, it shows potential applications in the design of erbium-doped fiber amplifiers. The absorption, the stimulated emission and the gain cross-sections of this transition have been obtained and compared with that obtained in different hosts. Finally, infrared-to-visible upconversion processes exciting at around 800 nm have been analyzed and different mechanisms involved in the energy conversion have been proposed. - Research highlights: → Broadened emission bands and high absorption and emission cross-sections for the transition 4 I 15/2 → 4 I 13/2 suitable for EDFAs. → Efficient green upconverted emission. → High value of C DA (6) energy transfer parameter.

  8. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  9. Tunable high-power narrow-spectrum external-cavity diode laser based on tapered amplifier at 668 nm

    DEFF Research Database (Denmark)

    Chi, Mingjun; Erbert, G.; Sumpf, B.

    2010-01-01

    A 668 nm tunable high-power narrow-spectrum diode laser system based on a tapered semiconductor optical amplifier in external cavity is demonstrated. The laser system is tunable from 659 to 675 nm. As high as 1.38 W output power is obtained at 668.35 nm. The emission spectral bandwidth is less than...

  10. Optical Filter Assembly for Interplanetary Optical Communications

    Science.gov (United States)

    Chen, Yijiang; Hemmati, Hamid

    2013-01-01

    Ground-based, narrow-band, high throughput optical filters are required for optical links from deep space. We report on the development of a tunable filter assembly that operates at telecommunication window of 1550 nanometers. Low insertion loss of 0.5 decibels and bandwidth of 90 picometers over a 2000 nanometers operational range of detectors has been achieved.

  11. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Change in the optical properties of hyaline cartilage heated by the near-IR laser radiation

    Science.gov (United States)

    Bagratashvili, Viktor N.; Bagratashvili, N. V.; Gapontsev, V. P.; Makhmutova, G. Sh; Minaev, V. P.; Omel'chenko, A. I.; Samartsev, I. E.; Sviridov, A. P.; Sobol', E. N.; Tsypina, S. I.

    2001-06-01

    The in vitro dynamics of the change in optical properties of hyaline cartilage heated by fibre lasers at wavelengths 0.97 and 1.56 μm is studied. The laser-induced bleaching (at 1.56 μm) and darkening (at 0.97 μm) of the cartilage, caused by the heating and transport of water as well as by a change in the cartilage matrix, were observed and studied. These effects should be taken into account while estimating the depth of heating of the tissue. The investigated dynamics of light scattering in the cartilage allows one to choose the optimum radiation dose for laser plastic surgery of cartilage tissues.

  12. A Mid-IR 14.1 W ZnGeP{sub 2} Optical Parametric Oscillator Pumped by a Tm,Ho:GdVO{sub 4} Laser

    Energy Technology Data Exchange (ETDEWEB)

    Guo-Li, Zhu; You-Lun, Ju; Tian-Heng, Wang; Yue-Zhu, Wang [National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2009-03-15

    We report a high power and high efficiency double resonant ZnGeP{sub 2} (ZGP) optical parametric oscillator (OPO) pumped by a Tm,Ho:GdVO{sub 4} laser. We employ a Tm,Ho:GdVO{sub 4} laser as the pump source operated at 2.049 {mu}m with M{sup 2} = 1.1. The ZGP OPO can generate a total combined output power of 14.1 W at 3.80 {mu}m signal and 4.45 {mu}m idler under pumping power of 28.7 W. The slope efficiency reaches 61.8%, and M{sup 2} = 3.6 for OPO output is obtained. (fundamental areas of phenomenology (including applications))

  13. Tunable optical properties of silymarin flavonolignans

    Czech Academy of Sciences Publication Activity Database

    Biler, M.; Trouillas, P.; Biedermann, David; Křen, Vladimír; Kubala, M.

    2016-01-01

    Roč. 328, SEP (2016), s. 154-162 ISSN 1010-6030 R&D Projects: GA MŠk(CZ) LD15084 Institutional support: RVO:61388971 Keywords : Silymarin * Flavonolignans * UV/Vis absorption Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.625, year: 2016

  14. IOT Overview: IR Instruments

    Science.gov (United States)

    Mason, E.

    In this instrument review chapter the calibration plans of ESO IR instruments are presented and briefly reviewed focusing, in particular, on the case of ISAAC, which has been the first IR instrument at VLT and whose calibration plan served as prototype for the coming instruments.

  15. Electrothermally Tunable Bridge Resonator

    KAUST Repository

    Hajjaj, Amal Z.; Alcheikh, Nouha; Ramini, Abdallah; Hafiz, Md Abdullah Al; Younis, Mohammad I.

    2016-01-01

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

  16. Electrothermally Tunable Bridge Resonator

    KAUST Repository

    Hajjaj, Amal Z.

    2016-12-05

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

  17. Lidar/DIAL detection of acetone at 3.3 μm by a tunable OPO laser system

    International Nuclear Information System (INIS)

    Puiu, A; Fiorani, L; Borelli, R; Pistilli, M; Palucci, A; Rosa, O

    2014-01-01

    In this paper we report, for the first time to our knowledge, on lidar/DIAL detection of acetone vapors at 3.3 μm by means of an optical parametric tunable laser system. After a preliminary spectroscopic study in an absorption cell, the feasibility of a differential absorption (DIAL) lidar for the detection of acetone vapors has been investigated in the laboratory, simulating the experimental conditions of a field campaign. Having in mind measurements in a real scenario, a study of possible atmospheric intereferents has been performed, looking for all known compounds that share acetone IR absorption in the spectral band selected for its detection. Possible interfering species from urban and industrial atmospheres were investigated and limits of acetone detection in both environments were identified. This study confirmed that a lidar system can detect a low concentration of acetone at considerable distances. (paper)

  18. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  19. Parametrically tunable soliton-induced resonant radiation by three-wave mixing

    DEFF Research Database (Denmark)

    Zhou, Binbin; Liu, Xing; Guo, Hairun

    2017-01-01

    We show that a temporal soliton can induce resonant radiation by three-wave mixing nonlinearities. This constitutes a new class of resonant radiation whose spectral positions are parametrically tunable. The experimental verification is done in a periodically poled lithium niobate crystal, where...... a femtosecond near-IR soliton is excited and resonant radiation waves are observed exactly at the calculated soliton phasematching wavelengths via the sum- and difference-frequency generation nonlinearities. This extends the supercontinuum bandwidth well into the mid IR to span 550–5000 nm, and the mid-IR edge...

  20. Comparison between liquid and solid tunable focus lenses

    International Nuclear Information System (INIS)

    Santiago-Alvarado, A; Cruz-Martinez, V M; Vazquez-Montiel, S; Munoz-Lopez, J; Diaz-Gonzalez, G; Campos-Garcia, M

    2011-01-01

    Nowadays more reports in the use of tunable lenses are reported, it is due to the benefits they offer in optical systems design. A tunable lens is an optical system that can focus on a range of positions by changing dynamically one of its geometric parameters. There are several types of tunable lenses, the most known types are the liquid, the solid elastic, with variable refractive index, and lenses that use a dielectric medium. This paper presents the analysis and opto-mechanical design of two tunable lenses, a liquid lens and another Solid Elastic Lens (SEL). Both lenses are made in mounting aluminium and polydimethylsiloxane (PDMS) as refractor medium, the liquid lens use two elastic membranes containing a liquid medium between them while the SEL only use PDMS material as body of the lens (medium refractor). We describe the opto-mechanical performance of both types of lens highlighting the main features of each. Finally, results of a opto-functional comparison between these prototypes are showed.

  1. Electrostatically Tunable Nanomechanical Shallow Arches

    KAUST Repository

    Kazmi, Syed N. R.

    2017-11-03

    We report an analytical and experimental study on the tunability of in-plane doubly-clamped nanomechanical arches under varied DC bias conditions at room temperature. For this purpose, silicon based shallow arches are fabricated using standard e-beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator (SOI) wafer. The experimental results show good agreement with the analytical results with a maximum tunability of 108.14% for 180 nm thick arch with a transduction gap of 1 μm between the beam and the driving/sensing electrodes. The high tunability of shallow arches paves the ways for highly tunable band pass filtering applications in high frequency range.

  2. Tunable radiation emitting semiconductor device

    NARCIS (Netherlands)

    2009-01-01

    A tunable radiation emitting semiconductor device includes at least one elongated structure at least partially fabricated from one or more semiconductor materials exhibiting a bandgap characteristic including one or more energy transitions whose energies correspond to photon energies of light

  3. A car-borne highly sensitive near-IR diode-laser methane detector

    International Nuclear Information System (INIS)

    Berezin, A G; Ershov, Oleg V; Shapovalov, Yu P

    2003-01-01

    A highly sensitive automated car-borne detector for measuring methane concentration in real time is designed, developed and tested under laboratory and field conditions. Measurements were made with the help of an uncooled tunable near-IR 1.65-μm laser diode. The detector consists of a multipass optical cell with a 45-m long optical path and a base length of 0.5 m. The car-borne detector is intended for monitoring the methane concentration in air from the moving car to reveal the leakage of domestic gas. The sensitivity limit (standard deviation) under field conditions is 1 ppm (20 ppb under laboratory conditions) for a measuring time of 0.4 s. The measuring technique based on the detection of a single methane line ensured a high selectivity of methane detector relative to other gases. The methane detector can be easily modified for measuring other simple-molecule gases (e.g., CO, CO 2 , HF, NO 2 , H 2 O) by replacing the diode laser and varying the parameters of the control program. (special issue devoted to the memory of academician a m prokhorov)

  4. Tunable on chip optofluidic laser

    DEFF Research Database (Denmark)

    Bakal, Avraham; Vannahme, Christoph; Kristensen, Anders

    2016-01-01

    On chip tunable laser is demonstrated by realizing a microfluidic droplet array. The periodicity is controlled by the pressure applied to two separate inlets, allowing to tune the lasing frequency over a broad spectral range.......On chip tunable laser is demonstrated by realizing a microfluidic droplet array. The periodicity is controlled by the pressure applied to two separate inlets, allowing to tune the lasing frequency over a broad spectral range....

  5. Tunable femtosecond Cherenkov fiber laser

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Svane, Ask Sebastian; Lægsgaard, Jesper

    2014-01-01

    We demonstrate electrically-tunable femtosecond Cherenkov fiber laser output at the visible range. Using an all-fiber, self-starting femtosecond Yb-doped fiber laser as the pump source and nonlinear photonic crystal fiber link as the wave-conversion medium, ultrafast, milliwatt-level, tunable...... and spectral isolated Cherenkov radiation at visible wavelengths are reported. Such a femtosecond Cherenkov laser source is promising for practical biophotonics applications....

  6. Structural, Spectroscopic (FT-IR, Raman and NMR, Non-linear Optical (NLO, HOMO-LUMO and Theoretical (DFT/CAM-B3LYP Analyses of N-Benzyloxycarbonyloxy-5-Norbornene-2,3-Dicarboximide Molecule

    Directory of Open Access Journals (Sweden)

    Nuri ÖZTÜRK

    2018-02-01

    Full Text Available The experimental spectroscopic investigation of N-benzyloxycarbonyloxy-5-norbornene-2,3-dicarboximide (C17H15NO5 molecule has been done using 1H and 13C NMR chemical shifts, FT-IR and Raman spectroscopies. Conformational forms have been determined depending on orientation of N-benzyloxycarbonyloxy and 5-norbornene-2,3-dicarboximide (NDI groups of the title compound. The structural geometric optimizations, vibrational wavenumbers, NMR chemical shifts (in vacuum and chloroform and HOMO-LUMO analyses for all conformers of the title molecule have been done with DFT/CAM-B3LYP method at the 6-311++G(d,p basis set. Additionally, based on the calculated HOMO and LUMO energy values, some molecular properties such as ionization potential (I, electron affinity (A, electronegativity (χ, chemical hardness (h, chemical softness (z, chemical potential (μ and electrophilicity index (w parameters are determined for all conformers. The non-linear optical (NLO properties have been studied for the title molecule. We can say that the experimental spectral data are in accordance with calculated values.

  7. Fleet Protection Using a Small UAV Based IR Sensor

    National Research Council Canada - National Science Library

    Buss, James R; Ax, Jr, George R

    2005-01-01

    A study was performed to define candidate electro-optical and infrared (EO/IR) sensor configurations and assess their potential utility as small UAV-based sensors surveilling a perimeter around surface fleet assets...

  8. FT-IR, RAMAN AND DFT STUDIES ON THE VIBRATIONAL ...

    African Journals Online (AJOL)

    Department of Physics, Science Faculty, Anadolu University, Eskişehir, Turkey ... IR spectrum was recorded using Bruker Optics IFS66v/s FTIR spectrometer at a ... spectrum was obtained using a Bruker Senterra Dispersive Raman microscope.

  9. Tunable submillimeter sources applied to the excited state rotational spectroscopy and kinetics of CH3F

    International Nuclear Information System (INIS)

    Blumberg, W.A.M.; Fetterman, H.R.; Peck, D.D.; Goldsmith, P.F.

    1979-01-01

    Tunable submillimeter radiation, generated and detected using optically pumped lasers and Schottky diode mixers, has been used in an infrared-submillimeter double resonance investigation of CH 3 F. This technique permits the direct observation of the molecular rotational spectra and kinetics of excited vibrational states and is particularly important for those molecules which are candidates for optically pumped submillimeter lasers

  10. Magnetostatic wave tunable resonators

    Science.gov (United States)

    Castera, J.-P.; Hartemann, P.

    1983-06-01

    Theoretical principles and techniques for the implementation of magnetostatic surface wave and volume wave resonators in high frequency oscillators are discussed. Magnetostatic waves are magnetic waves that propagate in materials exposed to a polarized magnetic field. The propagation speed ranges from 3-300 km/sec for wavelengths between 1 micron and 10 mm, in the presence of lags from 10-1000 nsec/ cm. Tunable resonators in the 1-20 GHz frequency range have been manufactured with YIG using liquid phase epitaxy for deposition on gadolinium and gallium substrates. Distributed-mirror Fabry-Perot cavity resonators are described and performance tests results are reported, including losses of 8 dB, a quality coefficient under voltage of 450, and frequency rejection outside of resonance better than 10 dB. However, saturation occurs at low power levels at frequencies lower than 4.2 GHz, a feature overcome with forward volume magnetostatic wave generators, which have a quality factor of 500, an insertion loss of 22 dB, and rejection around 15 dB.

  11. Chemical kinetic studies of atmospheric reactions using tunable diode laser spectroscopy

    Science.gov (United States)

    Worsnop, Douglas R.; Nelson, David D.; Zahniser, Mark S.

    1993-01-01

    IR absorption using tunable diode laser spectroscopy provides a sensitive and quantitative detection method for laboratory kinetic studies of atmospheric trace gases. Improvements in multipass cell design, real time signal processing, and computer controlled data acquisition and analysis have extended the applicability of the technique. We have developed several optical systems using off-axis resonator mirror designs which maximize path length while minimizing both the sample volume and the interference fringes inherent in conventional 'White' cells. Computerized signal processing using rapid scan (300 kHz), sweep integration with 100 percent duty cycle allows substantial noise reduction while retaining the advantages of using direct absorption for absolute absorbance measurements and simultaneous detection of multiple species. Peak heights and areas are determined by curve fitting using nonlinear least square methods. We have applied these techniques to measurements of: (1) heterogeneous uptake chemistry of atmospheric trace gases (HCl, H2O2, and N2O5) on aqueous and sulfuric acid droplets; (2) vapor pressure measurements of nitric acid and water over prototypical stratospheric aerosol (nitric acid trihydrate) surfaces; and (3) discharge flow tube kinetic studies of the HO2 radical using isotopic labeling for product channel and mechanistic analysis. Results from each of these areas demonstrate the versatility of TDL absorption spectroscopy for atmospheric chemistry applications.

  12. Widely tunable terahertz source based on intra-cavity frequency mixing in quantum cascade laser arrays

    International Nuclear Information System (INIS)

    Jiang, Aiting; Jung, Seungyong; Jiang, Yifan; Kim, Jae Hyun; Belkin, Mikhail A.; Vijayraghavan, Karun

    2015-01-01

    We demonstrate a compact monolithic terahertz source continuously tunable from 1.9 THz to 3.9 THz with the maximum peak power output of 106 μW at 3.46 THz at room temperature. The source consists of an array of 10 electrically tunable quantum cascade lasers with intra-cavity terahertz difference-frequency generation. To increase fabrication yield and achieve high THz peak power output in our devices, a dual-section current pumping scheme is implemented using two electrically isolated grating sections to independently control gain for the two mid-IR pumps

  13. Near-IR laser-based spectrophotometer for comparative analysis of isotope content of CO2 in exhale air samples

    International Nuclear Information System (INIS)

    Stepanov, E V; Glushko, A N; Kasoev, S G; Koval', A V; Lapshin, D A

    2011-01-01

    We present a laser spectrophotometer aimed at high-accuracy comparative analysis of content of 12 CO 2 and 13 CO 2 isotope modifications in the exhale air samples and based on a tunable near-IR diode laser (2.05 μm). The two-channel optical scheme of the spectrophotometer and the special digital system for its control are described. An algorithm of spectral data processing aimed at determining the difference in the isotope composition of gas mixtures is proposed. A few spectral regions (near 4880 cm -1 ) are determined to be optimal for analysis of relative content of 12 CO 2 and 13 CO 2 in the exhale air. The use of the proposed spectrophotometer scheme and the developed algorithm makes the results of the analysis less susceptible to the influence of the interference in optical elements, to the absorption in the open atmosphere, to the slow drift of the laser pulse envelope, and to the offset of optical channels. The sensitivity of the comparative analysis of the isotope content of CO 2 in exhale air samples, achieved using the proposed scheme, is estimated to be nearly 0.1‰.

  14. A versatile tunable microcavity for investigation of light-matter interaction

    Science.gov (United States)

    Mochalov, Konstantin E.; Vaskan, Ivan S.; Dovzhenko, Dmitriy S.; Rakovich, Yury P.; Nabiev, Igor

    2018-05-01

    Light-matter interaction between a molecular ensemble and a confined electromagnetic field is a promising area of research, as it allows light-control of the properties of coupled matter. The common way to achieve coupling is to place an ensemble of molecules or quantum emitters into a cavity. In this approach, light-matter coupling is evidenced by modification of the spectral response of the emitter, which depends on the strength of interaction between emitter and cavity modes. However, there is not yet a user-friendly approach that allows the study of a large number of different and replaceable samples in a wide optical range using the same resonator. Here, we present the design of such a device that can speed up and facilitate investigation of light-matter interaction ranging from weak to strong coupling regimes in ultraviolet-visible and infrared (IR) spectral regions. The device is based on a tunable unstable λ/2 Fabry-Pérot microcavity consisting of plane and convex mirrors that satisfy the plane-parallelism condition at least at one point of the curved mirror and minimize the mode volume. Fine tuning of the microcavity length is provided by a Z-piezopositioner in a range up to 10 μm with a step of several nm. This design makes a device a versatile instrument that ensures easy finding of optimal conditions for light-matter interaction for almost any sample in both visible and IR areas, enabling observation of both electronic and vibrational couplings with microcavity modes thus paving the way to investigation of various coupling effects including Raman scattering enhancement, modification of chemical reactivity rate, lasing, and long-distance nonradiative energy transfer.

  15. Tunable Multiband Microwave Photonic Filters

    Directory of Open Access Journals (Sweden)

    Mable P. Fok

    2017-11-01

    Full Text Available The increasing demand for multifunctional devices, the use of cognitive wireless technology to solve the frequency resource shortage problem, as well as the capabilities and operational flexibility necessary to meet ever-changing environment result in an urgent need of multiband wireless communications. Spectral filter is an essential part of any communication systems, and in the case of multiband wireless communications, tunable multiband RF filters are required for channel selection, noise/interference removal, and RF signal processing. Unfortunately, it is difficult for RF electronics to achieve both tunable and multiband spectral filtering. Recent advancements of microwave photonics have proven itself to be a promising candidate to solve various challenges in RF electronics including spectral filtering, however, the development of multiband microwave photonic filtering still faces lots of difficulties, due to the limited scalability and tunability of existing microwave photonic schemes. In this review paper, we first discuss the challenges that were facing by multiband microwave photonic filter, then we review recent techniques that have been developed to tackle the challenge and lead to promising developments of tunable microwave photonic multiband filters. The successful design and implementation of tunable microwave photonic multiband filter facilitate the vision of dynamic multiband wireless communications and radio frequency signal processing for commercial, defense, and civilian applications.

  16. Origami structures for tunable thermal expansion

    Science.gov (United States)

    Boatti, Elisa; Bertoldi, Katia

    Materials with engineered thermal expansion, capable of achieving targeted and extreme area/volume changes in response to variations in temperature, are important for a number of aerospace, optical, energy, and microelectronic applications. While most of the proposed structures with tunable coefficient of thermal expansion consist of bi-material 2D or 3D lattices, here we propose a periodic metastructure based on a bilayer Miura-Ori origami fold. We combine experiments and simulations to demonstrate that by tuning the geometrical and mechanical parameters an extremely broad range of thermal expansion coefficients can be obtained, spanning both negative and positive values. Additionally, the thermal properties along different directions can be adjusted independently. Differently from all previously reported systems, the proposed structure is non-porous.

  17. Tunable plasmonic lattices of silver nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Andrea; Sinsermsuksakul, Prasert; Yang, Peidong

    2008-02-18

    Silver nanocrystals are ideal building blocks for plasmonicmaterials that exhibit a wide range of unique and potentially usefuloptical phenomena. Individual nanocrystals display distinct opticalscattering spectra and can be assembled into hierarchical structures thatcouple strongly to external electromagnetic fields. This coupling, whichis mediated by surface plasmons, depends on their shape and arrangement.Here we demonstrate the bottom-up assembly of polyhedral silvernanocrystals into macroscopic two-dimensional superlattices using theLangmuir-Blodgett technique. Our ability to control interparticlespacing, density, and packing symmetry allows for tunability of theoptical response over the entire visible range. This assembly strategyoffers a new, practical approach to making novel plasmonic materials forapplication in spectroscopic sensors, sub-wavelength optics, andintegrated devices that utilize field enhancement effects.

  18. Strain-tunable quantum dot devices

    International Nuclear Information System (INIS)

    Rastelli, A.; Trotta, R.; Zallo, E.; Atkinson, P.; Magerl, E.; Ding, F.; Plumhof, J.D.; Kumar, S.; Doerr, K.; Schmidt, O.G.

    2011-01-01

    We introduce a new class of quantum dot-based devices, in which the semiconductor structures are integrated on top of piezoelectric actuators. This combination allows on one hand to study in detail the effects produced by variable strains (up to about 0.2%) on the excitonic emission of single quantum dots and on the other to manipulate their electronic- and optical properties to achieve specific requirements. In fact, by combining strain with electric fields we are able to obtain (i) independent control of emission energy and charge-state of a QD, (II) wavelength-tunable single-QD light-emitting diodes and (III) frequency-stabilized sources of single photons at predefined wavelengths. Possible future extensions and applications of this technology will be discussed.

  19. Effect of annealing temperature on optical properties of binary zinc tin oxide nano-composite prepared by sol-gel route using simple precursors: structural and optical studies by DRS, FT-IR, XRD, FESEM investigations.

    Science.gov (United States)

    Habibi, Mohammad Hossein; Mardani, Maryam

    2015-02-25

    Binary zinc tin oxide nano-composite was synthesized by a facile sol-gel method using simple precursors from the solutions consisting of zinc acetate, tin(IV) chloride and ethanol. Effect of annealing temperature on optical and structural properties was investigated using X-ray diffraction (XRD), diffuse reflectance spectra (DRS), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). XRD results revealed the existence of the ZnO and SnO2 phases. FESEM results showed that binary zinc tin oxide nano-composites ranges from 56 to 60 nm in diameter at 400°C and 500°C annealing temperatures respectively. The optical band gap was increased from 2.72 eV to 3.11 eV with the increasing of the annealing temperature. FTIR results confirmed the presence of zinc oxide and tin oxide and the broad absorption peaks at 3426 and 1602 cm(-1) can be ascribed to the vibration of absorptive water, and the absorption peaks at 546, 1038 and 1410 cm(-1) are due to the vibration of Zn-O or Sn-O groups in binary zinc tin oxide. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Solitonic supercontinuum of femtosecond mid-IR pulses in W-type index tellurite fibers with two zero dispersion wavelengths

    Directory of Open Access Journals (Sweden)

    S. Kedenburg

    2016-11-01

    Full Text Available We present a detailed experimental parameter study on mid-IR supercontinuum generation in W-type index tellurite fibers, which reveals how the core diameter, pump wavelength, fiber length, and pump power dramatically influence the spectral broadening. As pump source, we use femtosecond mid-IR pulses from a post-amplified optical parametric oscillator tunable between 1.7 μm and 4.1 μm at 43 MHz repetition rate. We are able to generate red-shifted dispersive waves up to a wavelength of 5.1 μm by pumping a tellurite fiber in the anomalous dispersion regime between its two zero dispersion wavelengths. Distinctive soliton dynamics can be identified as the main broadening mechanism resulting in a maximum spectral width of over 2000 nm with output powers of up to 160 mW. We experimentally demonstrated that efficient spectral broadening with considerably improved power proportion in the important first atmospheric transmission window between 3 and 5 μm can be achieved in robust W-type tellurite fibers pumped at long wavelengths by ultra-fast lasers.

  1. Wide-range tunable magnetic lens for tabletop electron microscope

    International Nuclear Information System (INIS)

    Chang, Wei-Yu; Chen, Fu-Rong

    2016-01-01

    A tabletop scanning electron microscope (SEM) utilizes permanent magnets as condenser lenses to minimize its size, but this sacrifices the tunability of condenser lenses such that a tabletop system can only be operated with a fixed accelerating voltage. In contrast, the traditional condenser lens utilizes an electromagnetic coil to adjust the optical properties, but the size of the electromagnetic lens is inevitably larger. Here, we propose a tunable condenser lens for a tabletop SEM that uses a combination of permanent magnets and electromagnetic coils. The overall dimensions of the newly designed lens are the same as the original permanent magnet lens, but the new lens allows the tabletop SEM to be operated at different accelerating voltages between 1 kV and 15 kV. - Highlights: • A compact condenser lens combines both permanent magnet and coils. • A tunable lens is designed to keep the same focal point for voltage 1 to 15 kV. • A miniature tunable lens which can directly fit into tabletop SEM.

  2. Wide-range tunable magnetic lens for tabletop electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Wei-Yu; Chen, Fu-Rong, E-mail: fchen1@me.com

    2016-12-15

    A tabletop scanning electron microscope (SEM) utilizes permanent magnets as condenser lenses to minimize its size, but this sacrifices the tunability of condenser lenses such that a tabletop system can only be operated with a fixed accelerating voltage. In contrast, the traditional condenser lens utilizes an electromagnetic coil to adjust the optical properties, but the size of the electromagnetic lens is inevitably larger. Here, we propose a tunable condenser lens for a tabletop SEM that uses a combination of permanent magnets and electromagnetic coils. The overall dimensions of the newly designed lens are the same as the original permanent magnet lens, but the new lens allows the tabletop SEM to be operated at different accelerating voltages between 1 kV and 15 kV. - Highlights: • A compact condenser lens combines both permanent magnet and coils. • A tunable lens is designed to keep the same focal point for voltage 1 to 15 kV. • A miniature tunable lens which can directly fit into tabletop SEM.

  3. The theoretical and numerical models of the novel and fast tunable semiconductor ring laser

    Science.gov (United States)

    Zhu, Jiangbo; Zhang, Junwen; Chi, Nan; Yu, Siyuan

    2011-01-01

    Fast wavelength-tunable semiconductor lasers will be the key components in future optical packet switching networks. Especially, they are of great importance in the optical network nodes: transmitters, optical wavelength-routers, etc. In this paper, a new scheme of a next-generation fast tunable ring laser was given. Tunable lasers in this design have better wavelength tunability compared with others, for they are switched faster in wavelength and simpler to control with the injecting light from an external distributed Bragg-reflector(DBR). Then some discussion of the waveguide material system and coupler design of the ring laser were given. And we also derived the multimode rate equations corresponding to this scheme by analyzing some characteristics of the semiconductor ring cavity, directionality, nonlinear mode competition, optical injection locking, etc. We did MatLab simulation based on the new rate equations to research the process of mode competition and wavelength switching in the laser, and achieved the basic functions of a tunable laser. Finally some discussion of the impact of several key parameters was given.

  4. Tunable Fiber Bragg Grating Ring Lasers using Macro Fiber Composite Actuators

    Science.gov (United States)

    Geddis, Demetris L.; Allison, Sidney G.; Shams, Qamar A.

    2006-01-01

    The research reported herein includes the fabrication of a tunable optical fiber Bragg grating (FBG) fiber ring laser (FRL)1 from commercially available components as a high-speed alternative tunable laser source for NASA Langley s optical frequency domain reflectometer (OFDR) interrogator, which reads low reflectivity FBG sensors. A Macro-Fiber Composite (MFC) actuator invented at NASA Langley Research Center (LaRC) was selected to tune the laser. MFC actuators use a piezoelectric sheet cut into uniaxially aligned rectangular piezo-fibers surrounded by a polymer matrix and incorporate interdigitated electrodes to deliver electric fields along the length of the piezo-fibers. This configuration enables MFC actuators to produce displacements larger than the original uncut piezoelectric sheet. The FBG filter was sandwiched between two MFC actuators, and when strained, produced approximately 3.62 nm of wavelength shift in the FRL when biasing the MFC actuators from 500 V to 2000 V. This tunability range is comparable to that of other tunable lasers and is adequate for interrogating FBG sensors using OFDR technology. Three different FRL configurations were studied. Configuration A examined the importance of erbium-doped fiber length and output coupling. Configuration B demonstrated the importance of the FBG filter. Configuration C added an output coupler to increase the output power and to isolate the filter. Only configuration C was tuned because it offered the best optical power output of the three configurations. Use of Plastic Optical Fiber (POF) FBG s holds promise for enhanced tunability in future research.

  5. Generation of single-frequency tunable green light in a coupled ring tapered diode laser cavity

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Petersen, Paul Michael

    2013-01-01

    in the broad wavelength range from 1049 nm to 1093 nm and the beam propagation factor is improved from M2 = 2.8 to below 1.1. The laser frequency is automatically locked to the cavity resonance frequency using optical feedback. Furthermore, we show that this adaptive external cavity approach leads to efficient......We report the realization of a tapered diode laser operated in a coupled ring cavity that significantly improves the coherence properties of the tapered laser and efficiently generates tunable light at the second harmonic frequency. The tapered diode laser is tunable with single-frequency output...... frequency doubling. More than 500 mW green output power is obtained by placing a periodically poled LiNbO3 crystal in the external cavity. The single frequency green output from the laser system is tunable in the 530 nm to 533 nm range limited by the LiNbO3 crystal. The optical to optical conversion...

  6. DFT Simulation of Structural and Optical Properties of 9-Aminoacridine Half-Sandwich Ru(II), Rh(III), and Ir(III) Antitumoral Complexes and Their Interaction with DNA.

    Science.gov (United States)

    Cerón-Carrasco, José Pedro; Ruiz, José; Vicente, Consuelo; de Haro, Concepción; Bautista, Delia; Zúñiga, José; Requena, Alberto

    2017-08-08

    In this work, we use DFT-based methods to simulate the chemical structures, optical properties, and interaction with DNA of a recently synthesized chelated C^N 9-aminoacridine arene Ru(II) anticancer agent and two new closely related Rh(III) and Ir(III) complexes using DFT-based methods. Four chemical models and a number of theoretical approaches, which representatively include the PBE0, B97D, ωB97X, ωB97X-D, M06, and M06-L density functionals and the LANL2DZ, def2-SVP, and def2-TZVP basis sets, are tested. The best overall accuracy/cost performance for the optimization process is reached at the ωB97X-D/def2-SVP and M06/def2-SVP levels of theory. Inclusion of explicit solvent molecules (CHCl 3 ) further refines the geometry, while taking into account the crystal network gives no significant improvements of the computed bond distances and angles. The analysis of the excited states reveals that the M06 level matches better the experimental absorption spectra, compared to ωB97X-D. The use of the M06/def2-SVP approach is therefore a well-balanced method to study theoretically the bioactivity of this type of antitumoral complexes, so we couple this TD-DFT approach to molecular dynamics simulations in order to assess their reactivity with DNA. The reported results demonstrate that these drugs could be used to inject electrons into DNA, which might broaden their applications in photoactivated chemotherapy and as new materials for DNA-based electrochemical nanodevices.

  7. Tunable features of magnetoelectric transformers.

    Science.gov (United States)

    Dong, Shuxiang; Zhai, Junyi; Priya, Shashank; Li, Jie-Fang; Viehland, Dwight

    2009-06-01

    We have found that magnetostrictive FeBSiC alloy ribbons laminated with piezoelectric Pb(Zr,Ti)O(3) fiber can act as a tunable transformer when driven under resonant conditions. These composites were also found to exhibit the strongest resonant magnetoelectric voltage coefficient of 750 V/cm-Oe. The tunable features were achieved by applying small dc magnetic biases of -5 transformer features can be attributed to large changes in the piezomagnetic coefficient and permeability of the magnetostrictive phase under H(dc).

  8. Coherent tunable far infrared radiation

    Science.gov (United States)

    Jennings, D. A.

    1989-01-01

    Tunable, CW, FIR radiation has been generated by nonlinear mixing of radiation from two CO2 lasers in a metal-insulator-metal (MIM) diode. The FIR difference-frequency power was radiated from the MIM diode antenna to a calibrated InSb bolometer. FIR power of 200 nW was generated by 250 mW from each of the CO2 lasers. Using the combination of lines from a waveguide CO2 laser, with its larger tuning range, with lines from CO2, N2O, and CO2-isotope lasers promises complete coverage of the entire FIR band with stepwise-tunable CW radiation.

  9. Efficient tunable luminescence of SiGe alloy sheet polymers

    International Nuclear Information System (INIS)

    Vogg, G.; Meyer, A. J.-P.; Miesner, C.; Brandt, M. S.; Stutzmann, M.

    2001-01-01

    Crystalline SiGe alloy sheet polymers were topotactically prepared from epitaxially grown calcium germanosilicide Ca(Si 1-x Ge x ) 2 precursor films in the whole composition range. These polygermanosilynes are found to be a well-defined mixture of the known siloxene and polygermyne sheet polymers with the OH groups exclusively bonded to silicon. The optical properties determined by photoluminescence and optical reflection measurements identify the mixed SiGe sheet polymers as direct semiconductors with efficient luminescence tunable in the energy range between 2.4 and 1.3 eV. [copyright] 2001 American Institute of Physics

  10. Tunable, Room Temperature THZ Emitters Based on Nonlinear Photonics

    Science.gov (United States)

    Sinha, Raju

    The Terahertz (1012 Hz) region of the electromagnetic spectrum covers the frequency range from roughly 300 GHz to 10 THz, which is in between the microwave and infrared regimes. The increasing interest in the development of ultra-compact, tunable room temperature Terahertz (THz) emitters with wide-range tunability has stimulated in-depth studies of different mechanisms of THz generation in the past decade due to its various potential applications such as biomedical diagnosis, security screening, chemical identification, life sciences and very high speed wireless communication. Despite the tremendous research and development efforts, all the available state-of-the-art THz emitters suffer from either being large, complex and costly, or operating at low temperatures, lacking tunability, having a very short spectral range and a low output power. Hence, the major objective of this research was to develop simple, inexpensive, compact, room temperature THz sources with wide-range tunability. We investigated THz radiation in a hybrid optical and THz micro-ring resonators system. For the first time, we were able to satisfy the DFG phase matching condition for the above-mentioned THz range in one single device geometry by employing a modal phase matching technique and using two separately designed resonators capable of oscillating at input optical waves and generated THz waves. In chapter 6, we proposed a novel plasmonic antenna geometry – the dimer rod-tapered antenna (DRTA), where we created a hot-spot in the nanogap between the dimer arms with a very large intensity enhancement of 4.1x105 at optical resonant wavelength. Then, we investigated DFG operation in the antenna geometry by incorporating a nonlinear nanodot in the hot-spot of the antenna and achieved continuously tunable enhanced THz radiation across 0.5-10 THz range. In chapter 8, we designed a multi-metallic resonators providing an ultrasharp toroidal response at THz frequency, then fabricated and

  11. Orthogonal linear polarization tunable-beat ring laser with a superluminescent diode

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Y.; Yoshino, T. [Department of Electronic Engineering, Faculty of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376 (Japan)

    1997-09-01

    An orthogonal linear polarization operated ring laser with a superluminescent diode has been demonstrated to generate a tunable optical beat signal. The ring cavity contains a superluminescent diode as the optical gain medium, Faraday rotators, and a variable phase retarder (Babinet-Soleil compensator). By controlling the retarder, we changed the beat frequency in the range from a few tens of megahertz to 100 MHz. {copyright} 1997 Optical Society of America

  12. Bandwidth tunable microwave photonic filter based on digital and analog modulation

    Science.gov (United States)

    Zhang, Qi; Zhang, Jie; Li, Qiang; Wang, Yubing; Sun, Xian; Dong, Wei; Zhang, Xindong

    2018-05-01

    A bandwidth tunable microwave photonic filter based on digital and analog modulation is proposed and experimentally demonstrated. The digital modulation is used to broaden the effective gain spectrum and the analog modulation is to get optical lines. By changing the symbol rate of data pattern, the bandwidth is tunable from 50 MHz to 700 MHz. The interval of optical lines is set according to the bandwidth of gain spectrum which is related to the symbol rate. Several times of bandwidth increase are achieved compared to a single analog modulation and the selectivity of the response is increased by 3.7 dB compared to a single digital modulation.

  13. Noise filtering in a multi-channel system using a tunable liquid crystal photonic bandgap fiber

    DEFF Research Database (Denmark)

    Petersen, Martin Nordal; Scolari, Lara; Tokle, Torger

    2008-01-01

    This paper reports on the first application of a liquid crystal infiltrated photonic bandgap fiber used as a tunable filter in an optical transmission system. The device allows low-cost amplified spontaneous emission (ASE) noise filtering and gain equalization with low insertion loss and broad...... tunability. System experiments show that the use of this filter increases for times the distance over which the optical signal-to-noise ratio (OSNR) is sufficient for error-free transmission with respect to the case in which no filtering is used....

  14. Microwave photonic filters using low-cost sources featuring tunability, reconfigurability and negative coefficients.

    Science.gov (United States)

    Capmany, José; Mora, José; Ortega, Beatriz; Pastor, Daniel

    2005-03-07

    We propose and experimentally demonstrate two configurations of photonic filters for the processing of microwave signals featuring tunability, reconfigurability and negative coefficients based on the use of low cost optical sources. The first option is a low power configuration based on spectral slicing of a broadband source. The second is a high power configuration based on fixed lasers. Tunability, reconfigurability and negative coefficients are achieved by means of a MEMS cross-connect, a variable optical attenuator array and simple 2x2 switches respectively.

  15. Electrostatically Tunable Nanomechanical Shallow Arches

    KAUST Repository

    Kazmi, Syed N. R.; Hajjaj, Amal Z.; Da Costa, Pedro M. F. J.; Younis, Mohammad I.

    2017-01-01

    -beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator (SOI) wafer. The experimental results show good agreement with the analytical results with a maximum tunability of 108.14% for 180 nm thick arch with a

  16. Free space broad-bandwidth tunable laser diode based on Littman configuration for 3D profile measurement

    Science.gov (United States)

    Shirazi, Muhammad Faizan; Kim, Pilun; Jeon, Mansik; Kim, Chang-Seok; Kim, Jeehyun

    2018-05-01

    We developed a tunable laser diode for an optical coherence tomography system that can perform three-dimensional profile measurement using an area scanning technique. The tunable laser diode is designed using an Eagleyard tunable laser diode with a galvano filter. The Littman free space configuration is used to demonstrate laser operation. The line- and bandwidths of this source are 0.27 nm (∼110 GHz) and 43 nm, respectively, at the center wavelength of 860 nm. The output power is 20 mW at an operating current of 150 mA. A step height target is imaged using a wide-area scanning system to show the measurement accuracy of the proposed tunable laser diode. A TEM grid is also imaged to measure the topography and thickness of the sample by proposed tunable laser diode.

  17. Wide range optofluidically tunable multimode interference fiber laser

    International Nuclear Information System (INIS)

    Antonio-Lopez, J E; LiKamWa, P; Sanchez-Mondragon, J J; May-Arrioja, D A

    2014-01-01

    An optofluidically tunable fiber laser based on multimode interference (MMI) effects with a wide tuning range is proposed and demonstrated. The tunable mechanism is based on an MMI fiber filter fabricated using a special fiber known as no-core fiber, which is a multimode fiber (MMF) without cladding. Therefore, when the MMI filter is covered by liquid the optical properties of the no-core fiber are modified, which allow us to tune the peak wavelength response of the MMI filter. Rather than applying the liquid on the entire no-core fiber, we change the liquid level along the no-core fiber, which provides a highly linear tuning response. In addition, by selecting the adequate refractive index of the liquid we can also choose the tuning range. We demonstrate the versatility of the optofluidically tunable MMI filter by wavelength tuning two different gain media, erbium doped fiber and a semiconductor optical amplifier, achieving tuning ranges of 55 and 90 nm respectively. In both cases, we achieve side-mode suppression ratios (SMSR) better than 50 dBm with output power variations of less than 0.76 dBm over the whole tuning range. (paper)

  18. Development of a diamond waveguide sensor for sensitive protein analysis using IR quantum cascade lasers

    Science.gov (United States)

    Piron, P.; Vargas Catalan, E.; Haas, J.; Österlund, L.; Nikolajeff, F.; Andersson, P. O.; Bergström, J.; Mizaikoff, B.; Karlsson, M.

    2018-02-01

    Microfabricated diamond waveguides, between 5 and 20 μm thick, manufactured by chemical vapor deposition of diamond, followed by standard lithographic techniques and inductively coupled plasma etching of diamond, are used as bio-chemical sensors in the mid infrared domain: 5-11 μm. Infrared light, emitted from a broadly tunable quantum cascade laser with a wavelength resolution smaller than 20 nm, is coupled through the diamond waveguides for attenuated total reflection spectroscopy. The expected advantages of these waveguides are a high sensitivity due to the high number of internal reflections along the propagation direction, a high transmittance in the mid-IR domain, the bio-compatibility of diamond and the possibility of functionalizing the surface layer. The sensor will be used for analyzing different forms of proteins such as α-synuclein which is relevant in understanding the mechanism behind Parkinson's disease. The fabrication process of the waveguide, its characteristics and several geometries are introduced. The optical setup of the biosensor is described and our first measurements on two analytes to demonstrate the principle of the sensing method will be presented. Future use of this sensor includes the functionalization of the diamond waveguide sensor surface to be able to fish out alpha-synuclein from cerebrospinal fluid.

  19. BOOTES-IR: near IR follow-up GRB observations by a robotic system

    International Nuclear Information System (INIS)

    Castro-Tirado, A.J.; Postrigo, A. de Ugarte; Jelinek, M.

    2005-01-01

    BOOTES-IR is the extension of the BOOTES experiment, which operates in Southern Spain since 1998, to the near IR (NIR). The goal is to follow up the early stage of the gamma ray burst (GRB) afterglow emission in the NIR, alike BOOTES does already at optical wavelengths. The scientific case that drives the BOOTES-IR performance is the study of GRBs with the support of spacecraft like INTEGRAL, SWIFT and GLAST. Given that the afterglow emission in both, the NIR and the optical, in the instances immediately following a GRB, is extremely bright (reached V = 8.9 in one case), it should be possible to detect this prompt emission at NIR wavelengths too. The combined observations by BOOTES-IR and BOOTES-1 and BOOTES-2 will allow for real time identification of trustworthy candidates to have a high redshift (z > 5). It is expected that, few minutes after a GRB, the IR magnitudes be H ∼ 7-10, hence very high quality spectra can be obtained for objects as far as z = 10 by larger instruments

  20. Moiré volume Bragg grating filter with tunable bandwidth.

    Science.gov (United States)

    Mokhov, Sergiy; Ott, Daniel; Divliansky, Ivan; Zeldovich, Boris; Glebov, Leonid

    2014-08-25

    We propose a monolithic large-aperture narrowband optical filter based on a moiré volume Bragg grating formed by two sequentially recorded gratings with slightly different resonant wavelengths. Such recording creates a spatial modulation of refractive index with a slowly varying sinusoidal envelope. By cutting a specimen at a small angle, to a thickness of one-period of this envelope, the longitudinal envelope profile will shift from a sine profile to a cosine profile across the face of the device. The transmission peak of the filter has a tunable bandwidth while remaining at a fixed resonant wavelength by a transversal shift of incidence position. Analytical expressions for the tunable bandwidth of such a filter are calculated and experimental data from a filter operating at 1064 nm with bandwidth range 30-90 pm is demonstrated.

  1. A dynamically-tunable graphene-based fano metasurface

    KAUST Repository

    Amin, Muhammad

    2013-09-01

    A planar graphene metasurface with rectangular holes, which is capable of supporting a dynamically tunable Fano resonance at Terahertz (THz) frequencies, is proposed. The rectangular hole is patterned asymmetrically within the metasurface\\'s unit cell to \\'brighten\\' an originally-dark quadrupolar surface plasmon mode. Fano resonance is achieved via the destructive interference of this mode with a dipolar surface plasmon. The spectral location and line shape of the Fano resonance can be dynamically tuned via a gate voltage applied to the metasurface to change graphene\\'s optical properties. The dynamic tunability of the Fano resonance suggests the applicability of the proposed metasurface in designing THz wave modulators and band-pass filters. © 2013 IEEE.

  2. Accuracy optimization with wavelength tunability in overlay imaging technology

    Science.gov (United States)

    Lee, Honggoo; Kang, Yoonshik; Han, Sangjoon; Shim, Kyuchan; Hong, Minhyung; Kim, Seungyoung; Lee, Jieun; Lee, Dongyoung; Oh, Eungryong; Choi, Ahlin; Kim, Youngsik; Marciano, Tal; Klein, Dana; Hajaj, Eitan M.; Aharon, Sharon; Ben-Dov, Guy; Lilach, Saltoun; Serero, Dan; Golotsvan, Anna

    2018-03-01

    As semiconductor manufacturing technology progresses and the dimensions of integrated circuit elements shrink, overlay budget is accordingly being reduced. Overlay budget closely approaches the scale of measurement inaccuracies due to both optical imperfections of the measurement system and the interaction of light with geometrical asymmetries of the measured targets. Measurement inaccuracies can no longer be ignored due to their significant effect on the resulting device yield. In this paper we investigate a new approach for imaging based overlay (IBO) measurements by optimizing accuracy rather than contrast precision, including its effect over the total target performance, using wavelength tunable overlay imaging metrology. We present new accuracy metrics based on theoretical development and present their quality in identifying the measurement accuracy when compared to CD-SEM overlay measurements. The paper presents the theoretical considerations and simulation work, as well as measurement data, for which tunability combined with the new accuracy metrics is shown to improve accuracy performance.

  3. Tunable quantum interference in a 3D integrated circuit.

    Science.gov (United States)

    Chaboyer, Zachary; Meany, Thomas; Helt, L G; Withford, Michael J; Steel, M J

    2015-04-27

    Integrated photonics promises solutions to questions of stability, complexity, and size in quantum optics. Advances in tunable and non-planar integrated platforms, such as laser-inscribed photonics, continue to bring the realisation of quantum advantages in computation and metrology ever closer, perhaps most easily seen in multi-path interferometry. Here we demonstrate control of two-photon interference in a chip-scale 3D multi-path interferometer, showing a reduced periodicity and enhanced visibility compared to single photon measurements. Observed non-classical visibilities are widely tunable, and explained well by theoretical predictions based on classical measurements. With these predictions we extract Fisher information approaching a theoretical maximum. Our results open a path to quantum enhanced phase measurements.

  4. Optical klystron FELs based on tandem electrostatic accelerators

    International Nuclear Information System (INIS)

    Gover, A.; Friedman, A.

    1989-01-01

    The operation of tandem electrostatic accelerator FELs in an optical klystron configuration makes it possible to take advantage of the high quality (low emittance and low energy spread) of the electron beam in electrostatic accelerators. With evolving microwiggler technology, state-of-the-art moderate energy (6-14-MeV) tandem electrostatic accelerators may be used for the development of highly coherent tunable radiation sources in the entire IR region. The authors present the general design considerations and the predicted operating characteristics of such devices and refer in specifics to a design of a 10-1000-μm FEL based on the parameters of a 5-6-MeV high current tandem accelerator. The operating wavelength of FELs is determined by the Doppler shift formula

  5. Stretchable Random Lasers with Tunable Coherent Loops.

    Science.gov (United States)

    Sun, Tzu-Min; Wang, Cih-Su; Liao, Chi-Shiun; Lin, Shih-Yao; Perumal, Packiyaraj; Chiang, Chia-Wei; Chen, Yang-Fang

    2015-12-22

    Stretchability represents a key feature for the emerging world of realistic applications in areas, including wearable gadgets, health monitors, and robotic skins. Many optical and electronic technologies that can respond to large strain deformations have been developed. Laser plays a very important role in our daily life since it was discovered, which is highly desirable for the development of stretchable devices. Herein, stretchable random lasers with tunable coherent loops are designed, fabricated, and demonstrated. To illustrate our working principle, the stretchable random laser is made possible by transferring unique ZnO nanobrushes on top of polydimethylsiloxane (PDMS) elastomer substrate. Apart from the traditional gain material of ZnO nanorods, ZnO nanobrushes were used as optical gain materials so they can serve as scattering centers and provide the Fabry-Perot cavity to enhance laser action. The stretchable PDMS substrate gives the degree of freedom to mechanically tune the coherent loops of the random laser action by changing the density of ZnO nanobrushes. It is found that the number of laser modes increases with increasing external strain applied on the PDMS substrate due to the enhanced possibility for the formation of coherent loops. The device can be stretched by up to 30% strain and subjected to more than 100 cycles without loss in laser action. The result shows a major advance for the further development of man-made smart stretchable devices.

  6. Compact tunable silicon photonic differential-equation solver for general linear time-invariant systems.

    Science.gov (United States)

    Wu, Jiayang; Cao, Pan; Hu, Xiaofeng; Jiang, Xinhong; Pan, Ting; Yang, Yuxing; Qiu, Ciyuan; Tremblay, Christine; Su, Yikai

    2014-10-20

    We propose and experimentally demonstrate an all-optical temporal differential-equation solver that can be used to solve ordinary differential equations (ODEs) characterizing general linear time-invariant (LTI) systems. The photonic device implemented by an add-drop microring resonator (MRR) with two tunable interferometric couplers is monolithically integrated on a silicon-on-insulator (SOI) wafer with a compact footprint of ~60 μm × 120 μm. By thermally tuning the phase shifts along the bus arms of the two interferometric couplers, the proposed device is capable of solving first-order ODEs with two variable coefficients. The operation principle is theoretically analyzed, and system testing of solving ODE with tunable coefficients is carried out for 10-Gb/s optical Gaussian-like pulses. The experimental results verify the effectiveness of the fabricated device as a tunable photonic ODE solver.

  7. Design of multi-wavelength tunable filter based on Lithium Niobate

    Science.gov (United States)

    Zhang, Ailing; Yao, Yuan; Zhang, Yue; Song, Hongyun

    2018-05-01

    A multi-wavelength tunable filter is designed. It consists of multiple waveguides among multiple waveguide gratings. A pair of electrodes were placed on both sides of each waveguide. The tunable filter uses the electro-optic effect of Lithium Niobate to tune the phase caused by each waveguide. Consequently, the wavelength and wavelength spacing of the filter are tuned by changing external voltages added on the electrode pairs. The tunable property of the filter is analyzed by phase matching condition and transfer-matrix method. Numerical results show that not only multiple wavelengths with narrow bandwidth are tuned with nearly equal spacing by synchronously changing the voltages added on all electrode pairs, but also the number of wavelengths is determined by the number of phase shifts caused by electrode pairs. Furthermore, due to the electro-optic effect of Lithium Niobate, the tuning speed of the filter can reach the order of ns.

  8. Tunable complex-valued multi-tap microwave photonic filter based on single silicon-on-insulator microring resonator.

    Science.gov (United States)

    Lloret, Juan; Sancho, Juan; Pu, Minhao; Gasulla, Ivana; Yvind, Kresten; Sales, Salvador; Capmany, José

    2011-06-20

    A complex-valued multi-tap tunable microwave photonic filter based on single silicon-on-insulator microring resonator is presented. The degree of tunability of the approach involving two, three and four taps is theoretical and experimentally characterized, respectively. The constraints of exploiting the optical phase transfer function of a microring resonator aiming at implementing complex-valued multi-tap filtering schemes are also reported. The trade-off between the degree of tunability without changing the free spectral range and the number of taps is studied in-depth. Different window based scenarios are evaluated for improving the filter performance in terms of the side-lobe level.

  9. Thermal-to-visible transducer (TVT) for thermal-IR imaging

    Science.gov (United States)

    Flusberg, Allen; Swartz, Stephen; Huff, Michael; Gross, Steven

    2008-04-01

    We have been developing a novel thermal-to-visible transducer (TVT), an uncooled thermal-IR imager that is based on a Fabry-Perot Interferometer (FPI). The FPI-based IR imager can convert a thermal-IR image to a video electronic image. IR radiation that is emitted by an object in the scene is imaged onto an IR-absorbing material that is located within an FPI. Temperature variations generated by the spatial variations in the IR image intensity cause variations in optical thickness, modulating the reflectivity seen by a probe laser beam. The reflected probe is imaged onto a visible array, producing a visible image of the IR scene. This technology can provide low-cost IR cameras with excellent sensitivity, low power consumption, and the potential for self-registered fusion of thermal-IR and visible images. We will describe characteristics of requisite pixelated arrays that we have fabricated.

  10. Temperature-dependent absorption cross-section measurements of 1-butene (1-C4H8) in VUV and IR

    KAUST Repository

    Es-sebbar, Et-touhami; Bé nilan, Yves; Farooq, Aamir

    2013-01-01

    synchrotron radiation as a tunable VUV light source. Fourier Transform Infrared (FTIR) spectroscopy is employed to measure absorption cross-section and band strengths in the IR region between 1.54 and 25μm (~6500-400cm-1). The measured room-temperature VUV

  11. Efficient control of ultrafast optical nonlinearity of reduced graphene oxide by infrared reduction

    Energy Technology Data Exchange (ETDEWEB)

    Bhattachraya, S.; Maiti, R.; Das, A. C.; Saha, S.; Mondal, S.; Ray, S. K.; Bhaktha, S. N. B.; Datta, P. K., E-mail: pkdatta.iitkgp@gmail.com [Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2016-07-07

    Simultaneous occurrence of saturable absorption nonlinearity and two-photon absorption nonlinearity in the same medium is well sought for the devices like optical limiter and laser mode-locker. Pristine graphene sheet consisting entirely of sp{sup 2}-hybridized carbon atoms has already been identified having large optical nonlinearity. However, graphene oxide (GO), a precursor of graphene having both sp{sup 2} and sp{sup 3}-hybridized carbon atom, is increasingly attracting cross-discipline researchers for its controllable properties by reduction of oxygen containing groups. In this work, GO has been prepared by modified Hummers method, and it has been further reduced by infrared (IR) radiation. Characterization of reduced graphene oxide (RGO) by means of Raman spectroscopy, X-ray photoelectron spectroscopy, and UV-Visible absorption measurements confirms an efficient reduction with infrared radiation. Here, we report precise control of non-linear optical properties of RGO in femtosecond regime with increased degrees of IR reduction measured by open aperture z-scan technique. Depending on the intensity, both saturable absorption and two-photon absorption effects are found to contribute to the non-linearity of all the samples. Saturation dominates at low intensity (∼127 GW/cm{sup 2}) while two-photon absorption becomes prominent at higher intensities (from 217 GW/cm{sup 2} to 302 GW/cm{sup 2}). The values of two-photon absorption co-efficient (∼0.0022–0.0037 cm/GW for GO, and ∼0.0128–0.0143 cm/GW for RGO) and the saturation intensity (∼57 GW/cm{sup 2} for GO, and ∼194 GW/cm{sup 2} for RGO) increase with increasing reduction, indicating GO and RGO as novel tunable photonic devices. We have also explained the reason of tunable nonlinear optical properties by using amorphous carbon model.

  12. Efficient control of ultrafast optical nonlinearity of reduced graphene oxide by infrared reduction

    International Nuclear Information System (INIS)

    Bhattachraya, S.; Maiti, R.; Das, A. C.; Saha, S.; Mondal, S.; Ray, S. K.; Bhaktha, S. N. B.; Datta, P. K.

    2016-01-01

    Simultaneous occurrence of saturable absorption nonlinearity and two-photon absorption nonlinearity in the same medium is well sought for the devices like optical limiter and laser mode-locker. Pristine graphene sheet consisting entirely of sp"2-hybridized carbon atoms has already been identified having large optical nonlinearity. However, graphene oxide (GO), a precursor of graphene having both sp"2 and sp"3-hybridized carbon atom, is increasingly attracting cross-discipline researchers for its controllable properties by reduction of oxygen containing groups. In this work, GO has been prepared by modified Hummers method, and it has been further reduced by infrared (IR) radiation. Characterization of reduced graphene oxide (RGO) by means of Raman spectroscopy, X-ray photoelectron spectroscopy, and UV-Visible absorption measurements confirms an efficient reduction with infrared radiation. Here, we report precise control of non-linear optical properties of RGO in femtosecond regime with increased degrees of IR reduction measured by open aperture z-scan technique. Depending on the intensity, both saturable absorption and two-photon absorption effects are found to contribute to the non-linearity of all the samples. Saturation dominates at low intensity (∼127 GW/cm"2) while two-photon absorption becomes prominent at higher intensities (from 217 GW/cm"2 to 302 GW/cm"2). The values of two-photon absorption co-efficient (∼0.0022–0.0037 cm/GW for GO, and ∼0.0128–0.0143 cm/GW for RGO) and the saturation intensity (∼57 GW/cm"2 for GO, and ∼194 GW/cm"2 for RGO) increase with increasing reduction, indicating GO and RGO as novel tunable photonic devices. We have also explained the reason of tunable nonlinear optical properties by using amorphous carbon model.

  13. Novel optical probe for quantum Hall system

    Indian Academy of Sciences (India)

    to explore Landau levels of a two-dimensional electron gas (2DEG) in modulation doped ... Keywords. Surface photovoltage spectroscopy; quantum Hall effect; Landau levels; edge states. ... An optical fibre carries light from tunable diode laser.

  14. Micromachined tunable metamaterials: a review

    International Nuclear Information System (INIS)

    Liu, A Q; Zhu, W M; Tsai, D P; Zheludev, N I

    2012-01-01

    This paper reviews micromachined tunable metamaterials, whereby the tuning capabilities are based on the mechanical reconfiguration of the lattice and/or the metamaterial element geometry. The primary focus of this review is the feasibility of the realization of micromachined tunable metamaterials via structure reconfiguration and the current state of the art in the fabrication technologies of structurally reconfigurable metamaterial elements. The micromachined reconfigurable microstructures not only offer a new tuning method for metamaterials without being limited by the nonlinearity of constituent materials, but also enable a new paradigm of reconfigurable metamaterial-based devices with mechanical actuations. With recent development in nanomachining technology, it is possible to develop structurally reconfigurable metamaterials with faster tuning speed, higher density of integration and more flexible choice of the working frequencies. (review article)

  15. Widely tunable THz synthesizer

    Science.gov (United States)

    Hindle, F.; Mouret, G.; Eliet, S.; Guinet, M.; Cuisset, A.; Bocquet, R.; Yasui, T.; Rovera, D.

    2011-09-01

    The generation of cw-THz radiation by photomixing is particularly suited to the high resolution spectroscopy of gases; nevertheless, until recently, it has suffered from a lack of frequency metrology. Frequency combs are a powerful tool that can transfer microwave frequency standards to optical frequencies and a single comb has permitted accurate (10-8) THz frequency synthesis with a limited tuning range. A THz synthesizer composed of three extended cavity laser diodes phase locked to a frequency comb has been constructed and its utility for high resolution gas phase spectroscopy demonstrated. The third laser diode allows a larger tuning range of up to 300 MHz to be achieved without the need for large frequency excursions, while the frequency comb provides a versatile link to be established from any traceable microwave frequency standard. The use of a single frequency comb as a reference for all of the cw-lasers eliminates the dependency of synthesized frequency on the carrier envelope offset frequency. This greatly simplifies the frequency comb stabilization requirements and leads to a reduced instrument complexity.

  16. Highly tunable NEMS shallow arches

    KAUST Repository

    Kazmi, Syed N. R.

    2017-11-30

    We report highly tunable nanoelectromechanical systems NEMS shallow arches under dc excitation voltages. Silicon based in-plane doubly clamped bridges, slightly curved as shallow arches, are fabricated using standard electron beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator wafer. By designing the structures to have gap to thickness ratio of more than four, the mid-plane stretching of the nano arches is maximized such that an increase in the dc bias voltage will result into continuous increase in the resonance frequency of the resonators to wide ranges. This is confirmed analytically based on a nonlinear beam model. The experimental results are found to be in good agreement with that of the results from developed analytical model. A maximum tunability of 108.14% for a 180 nm thick arch with an initially designed gap of 1 μm between the beam and the driving/sensing electrodes is achieved. Furthermore, a tunable narrow bandpass filter is demonstrated, which opens up opportunities for designing such structures as filtering elements in high frequency ranges.

  17. Highly Tunable Electrostatic Nanomechanical Resonators

    KAUST Repository

    Kazmi, Syed Naveed Riaz

    2017-11-24

    There has been significant interest towards highly tunable resonators for on-demand frequency selection in modern communication systems. Here, we report highly tunable electrostatically actuated silicon-based nanomechanical resonators. In-plane doubly-clamped bridges, slightly curved as shallow arches due to residual stresses, are fabricated using standard electron beam lithography and surface nanomachining. The resonators are designed such that the effect of mid-plane stretching dominates the softening effect of the electrostatic force. This is achieved by controlling the gap-to-thickness ratio and by exploiting the initial curvature of the structure from fabrication. We demonstrate considerable increase in the resonance frequency of nanoresonators with the dc bias voltages up to 108% for 180 nm thick structures with a transduction gap of 1 $mu$m separating them from the driving/sensing electrodes. The experimental results are found in good agreement with those of a nonlinear analytical model based on the Euler-Bernoulli beam theory. As a potential application, we demonstrate a tunable narrow band-pass filter using two electrically coupled nanomechanical arch resonators with varied dc bias voltages.

  18. Highly Tunable Electrostatic Nanomechanical Resonators

    KAUST Repository

    Kazmi, Syed Naveed Riaz; Hajjaj, Amal Z.; Hafiz, Md Abdullah Al; Da Costa, Pedro M. F. J.; Younis, Mohammad I.

    2017-01-01

    There has been significant interest towards highly tunable resonators for on-demand frequency selection in modern communication systems. Here, we report highly tunable electrostatically actuated silicon-based nanomechanical resonators. In-plane doubly-clamped bridges, slightly curved as shallow arches due to residual stresses, are fabricated using standard electron beam lithography and surface nanomachining. The resonators are designed such that the effect of mid-plane stretching dominates the softening effect of the electrostatic force. This is achieved by controlling the gap-to-thickness ratio and by exploiting the initial curvature of the structure from fabrication. We demonstrate considerable increase in the resonance frequency of nanoresonators with the dc bias voltages up to 108% for 180 nm thick structures with a transduction gap of 1 $mu$m separating them from the driving/sensing electrodes. The experimental results are found in good agreement with those of a nonlinear analytical model based on the Euler-Bernoulli beam theory. As a potential application, we demonstrate a tunable narrow band-pass filter using two electrically coupled nanomechanical arch resonators with varied dc bias voltages.

  19. Airborne pipeline leak detection: UV or IR?

    Science.gov (United States)

    Babin, François; Gravel, Jean-François; Allard, Martin

    2016-05-01

    This paper presents a study of different approaches to the measurement of the above ground vapor plume created by the spill caused by a small 0.1 l/min (or less) leak in an underground liquid petroleum pipeline. The scenarios are those for the measurement from an airborne platform. The usual approach is that of IR absorption, but in the case of liquid petroleum products, there are drawbacks that will be discussed, especially when using alkanes to detect a leak. The optical measurements studied include UV enhanced Raman lidar, UV fluorescence lidar and IR absorption path integrated lidars. The breadboards used for testing the different approaches will be described along with the set-ups for leak simulation. Although IR absorption would intuitively be the most sensitive, it is shown that UV-Raman could be an alternative. When using the very broad alkane signature in the IR, the varying ground spectral reflectance are a problem. It is also determined that integrated path measurements are preferred, the UV enhanced Raman measurements showing that the vapor plume stays very close to the ground.

  20. Narrowband widely tunable CW mid-infrared generator based on difference frequency generation in periodically poled KTP and KTA crystals

    Czech Academy of Sciences Publication Activity Database

    Baravets, Yauhen; Honzátko, Pavel; Todorov, Filip; Gladkov, Petar

    2016-01-01

    Roč. 48, č. 5 (2016), May ISSN 0306-8919 R&D Projects: GA MŠk LD14112 Grant - others:COST(XE) MP1204 Institutional support: RVO:67985882 Keywords : Fiber optics amplifiers * Difference-frequency generation * Mid-infrared tunable laser source Subject RIV: BH - Optics , Masers, Lasers Impact factor: 1.055, year: 2016

  1. High tunability and superluminescence in InAs mid-infrared light emitting diodes

    International Nuclear Information System (INIS)

    Sherstnev, V.V.; Krier, A.; Hill, G.

    2002-01-01

    We report on the observation of super luminescence and high spectral current tunability (181 nm) of InAs light emitting diodes operating at 3.0 μm. The source is based on an optical whispering gallery mode which is generated near the edges of the mesa and which is responsible for the superluminescence. (author)

  2. Development of coherent tunable source in 2–16 μm region using ...

    Indian Academy of Sciences (India)

    2014-01-09

    Jan 9, 2014 ... A very convenient way to obtain widely tunable source of coherent radiation in the infrared region is through nonlinear frequency mixing processes like second harmonic generation (SHG), difference-frequency mixing (DFM) or optical parametric oscillation (OPO). Using commonly available Nd:YAG laser ...

  3. IR and the Earth

    DEFF Research Database (Denmark)

    Corry, Olaf; Stevenson, Hayley

    2017-01-01

    , in the end, one finite interconnected space. Together these two starting points make for the basic conundrum of Inter- national Relations and the Earth: how does a divided world live on a single globe? This introduction first provides an overview of the recent rise of ‘the environment’ in international......, ‘what has the environment ever done for IR?’, before the plan for the rest of the book sketches the content and direction of the ensuing chapters that explore the problematique of International Relations and the Earth....

  4. Multichannel Dynamic Fourier-Transform IR Spectrometer

    Science.gov (United States)

    Balashov, A. A.; Vaguine, V. A.; Golyak, Il. S.; Morozov, A. N.; Khorokhorin, A. I.

    2017-09-01

    A design of a multichannel continuous scan Fourier-transform IR spectrometer for simultaneous recording and analysis of the spectral characteristics of several objects is proposed. For implementing the design, a multi-probe fiber is used, constructed from several optical fibers connected into a single optical connector and attached at the output of the interferometer. The Fourier-transform spectrometer is used as a signal modulator. Each fiber is individually mated with an investigated sample and a dedicated radiation detector. For the developed system, the radiation intensity of the spectrometer is calculated from the condition of the minimum spectral resolution and parameters of the optical fibers. Using the proposed design, emission spectra of a gas-discharge neon lamp have been recorded using a single fiber 1 mm in diameter with a numerical aperture NA = 0.22.

  5. Antenna Miniaturization with MEMS Tunable Capacitors

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

    2014-01-01

    In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss and their characterist......In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss...

  6. Nanoparticles with tunable shape and composition fabricated by nanoimprint lithography

    International Nuclear Information System (INIS)

    Alayo, Nerea; Bausells, Joan; Pérez-Murano, Francesc; Conde-Rubio, Ana; Labarta, Amilcar; Batlle, Xavier; Borrisé, Xavier

    2015-01-01

    Cone-like and empty cup-shaped nanoparticles of noble metals have been demonstrated to provide extraordinary optical properties for use as optical nanoanntenas or nanoresonators. However, their large-scale production is difficult via standard nanofabrication methods. We present a fabrication approach to achieve arrays of nanoparticles with tunable shape and composition by a combination of nanoimprint lithography, hard-mask definition and various forms of metal deposition. In particular, we have obtained arrays of empty cup-shaped Au nanoparticles showing an optical response with distinguishable features associated with the excitations of localized surface plasmons. Finally, this route avoids the most common drawbacks found in the fabrication of nanoparticles by conventional top-down methods, such as aspect ratio limitation, blurring, and low throughput, and it can be used to fabricate nanoparticles with heterogeneous composition. (paper)

  7. Nanoparticles with tunable shape and composition fabricated by nanoimprint lithography.

    Science.gov (United States)

    Alayo, Nerea; Conde-Rubio, Ana; Bausells, Joan; Borrisé, Xavier; Labarta, Amilcar; Batlle, Xavier; Pérez-Murano, Francesc

    2015-11-06

    Cone-like and empty cup-shaped nanoparticles of noble metals have been demonstrated to provide extraordinary optical properties for use as optical nanoanntenas or nanoresonators. However, their large-scale production is difficult via standard nanofabrication methods. We present a fabrication approach to achieve arrays of nanoparticles with tunable shape and composition by a combination of nanoimprint lithography, hard-mask definition and various forms of metal deposition. In particular, we have obtained arrays of empty cup-shaped Au nanoparticles showing an optical response with distinguishable features associated with the excitations of localized surface plasmons. Finally, this route avoids the most common drawbacks found in the fabrication of nanoparticles by conventional top-down methods, such as aspect ratio limitation, blurring, and low throughput, and it can be used to fabricate nanoparticles with heterogeneous composition.

  8. Fast tunable blazed MEMS grating for external cavity lasers

    Science.gov (United States)

    Tormen, Maurizio; Niedermann, Philippe; Hoogerwerf, Arno; Shea, Herbert; Stanley, Ross

    2017-11-01

    Diffractive MEMS are interesting for a wide range of applications, including displays, scanners or switching elements. Their advantages are compactness, potentially high actuation speed and in the ability to deflect light at large angles. We have designed and fabricated deformable diffractive MEMS grating to be used as tuning elements for external cavity lasers. The resulting device is compact, has wide tunability and a high operating speed. The initial design is a planar grating where the beams are free-standing and attached to each other using leaf springs. Actuation is achieved through two electrostatic comb drives at either end of the grating. To prevent deformation of the free-standing grating, the device is 10 μm thick made from a Silicon on Insulator (SOI) wafer in a single mask process. At 100V a periodicity tuning of 3% has been measured. The first resonant mode of the grating is measured at 13.8 kHz, allowing high speed actuation. This combination of wide tunability and high operating speed represents state of the art in the domain of tunable MEMS filters. In order to improve diffraction efficiency and to expand the usable wavelength range, a blazed version of the deformable MEMS grating has been designed. A key issue is maintaining the mechanical properties of the original device while providing optically smooth blazed beams. Using a process based on anisotropic KOH etching, blazed gratings have been obtained and preliminary characterization is promising.

  9. IR technology for enhanced force protection by AIM

    Science.gov (United States)

    Breiter, R.; Ihle, T.; Rode, W.; Wendler, J.; Rühlich, I.; Haiml, M.; Ziegler, J.

    2008-04-01

    In all recent missions our forces are faced with various types of asymmetric threads like snipers, IEDs, RPGs or MANPADS. 2 nd and 3 rd Gen IR technology is a backbone of modern force protection by providing situational awareness and accurate target engagement at day/night. 3 rd Gen sensors are developed for thread warning capabilities by use of spectral or spatial information. The progress on a dual-color IR module is discussed in a separate paper [1]. A 1024x256 SWIR array with flexure bearing compressor and pulse tube cold finger provides > 50,000h lifetime for space or airborne hyperspectral imaging in pushbroom geometry with 256 spectral channels for improved change detection and remote sensing of IEDs or chemical agents. Similar concepts are pursued in the LWIR with either spectroscopic imaging or a system of LWIR FPA combined with a cooled tunable Laser to do spectroscopy with stimulated absorption of specific wavelengths. AIM introduced the RangIR sight to match the requirements of sniper teams, AGLs and weapon stations, extending the outstanding optronic performance of the fielded HuntIR with position data of a target by a laser range finder (LRF), a 3 axis digital magnetic compass (DMC) and a ballistic computer for accurate engagement of remote targets. A version with flexure bearing cooler with >30,000h life time is being developed for continuous operation in e.g. gunfire detection systems. This paper gives an overview of AIM's technologies for enhanced force protection.

  10. Detailed IR aperture measurements

    CERN Document Server

    Bruce, Roderik; Garcia Morales, Hector; Giovannozzi, Massimo; Hermes, Pascal Dominik; Mirarchi, Daniele; Quaranta, Elena; Redaelli, Stefano; Rossi, Carlo; Skowronski, Piotr Krzysztof; Wretborn, Sven Joel; CERN. Geneva. ATS Department

    2016-01-01

    MD 1673 was carried out on October 5 2016, in order to investigate in more detail the available aperture in the LHC high-luminosity insertions at 6.5 TeV and β∗=40 cm. Previous aperture measurements in 2016 during commissioning had shown that the available aperture is at the edge of protection, and that the aperture bottleneck at β∗=40 cm in certain cases is found in the separation plane instead of in the crossing plane. Furthermore, the bottlenecks were consistently found in close to the upstream end of Q3 on the side of the incoming beam, and not in Q2 on the outgoing beam as expected from calculations. Therefore, this MD aimed at measuring IR1 and IR5 separately (at 6.5 TeV and β∗=40 cm, for 185 µrad half crossing angle), to further localize the bottlenecks longitudinally using newly installed BLMs, investigate the difference in aperture between Q2 and Q3, and to see if any aperture can be gained using special orbit bumps.

  11. Generation of phase-locked and tunable continuous-wave radiation in the terahertz regime.

    Science.gov (United States)

    Quraishi, Qudsia; Griebel, Martin; Kleine-Ostmann, Thomas; Bratschitsch, Rudolf

    2005-12-01

    Broadly tunable phase-stable single-frequency terahertz radiation is generated with an optical heterodyne photomixer. The photomixer is excited by two near-infrared CW diode lasers that are phase locked to the stabilized optical frequency comb of a femtosecond titanium:sapphire laser. The terahertz radiation emitted by the photomixer is downconverted into RF frequencies with a waveguide harmonic mixer and measurement-limited linewidths at the Hertz level are demonstrated.

  12. Tunable Multilayer Graphene Metamaterials for Terahertz/Infrared Waveguide Modulators

    DEFF Research Database (Denmark)

    Khromova, Irina; Andryieuski, Andrei; Lavrinenko, Andrei

    regimes of multilayer graphene-dielectric artificial metamaterials. The interplay between interband and intraband transitions in graphene allows converting the structure into a transparent and/or electromagnetically dense artificial medium. The gate voltage can be used to electrically control...... the concentration of carriers in the graphene sheets and, thus, efficiently change the dispersion of the whole structure. Placed inside a hollow waveguide, a multilayer graphene/dielectric metamaterial provides high-speed modulation and tunable bandpass filtering. The absence of scattered radiation enables dense...... the latter to shift its central frequency by 1:25% per every meV graphene Fermi energy change. We believe that graphene-dielectric multilayer metamaterials will constitute the functional platform for THz-IR waveguide-integrated devices....

  13. Rapid calibrated high-resolution hyperspectral imaging using tunable laser source

    Science.gov (United States)

    Nguyen, Lam K.; Margalith, Eli

    2009-05-01

    We present a novel hyperspectral imaging technique based on tunable laser technology. By replacing the broadband source and tunable filters of a typical NIR imaging instrument, several advantages are realized, including: high spectral resolution, highly variable field-of-views, fast scan-rates, high signal-to-noise ratio, and the ability to use optical fiber for efficient and flexible sample illumination. With this technique, high-resolution, calibrated hyperspectral images over the NIR range can be acquired in seconds. The performance of system features will be demonstrated on two example applications: detecting melamine contamination in wheat gluten and separating bovine protein from wheat protein in cattle feed.

  14. A dual-wavelength tunable laser with superimposed fiber Bragg gratings

    International Nuclear Information System (INIS)

    Álvarez-Tamayo, R I; Durán-Sánchez, M; Pottiez, O; Ibarra-Escamilla, B; Kuzin, E A; Cruz, J L; Andrés, M V

    2013-01-01

    We report a dual-wavelength tunable fiber laser. The cavity is formed by two superimposed fiber Bragg gratings (FBGs) and a temperature tunable high-birefringence fiber optical loop mirror (FOLM). FBGs with wavelengths of 1548.5 and 1538.5 nm were printed in the same section of a fiber using two different masks. The superimposed FBGs were placed on a mechanical mount that allows stretch or compression of the FBGs. As a result of the FBG strain both lines are shifted simultaneously. Dual-wavelength generation requires a fine adjustment of the cavity loss for both wavelengths. (paper)

  15. Tunable narrow band difference frequency THz wave generation in DAST via dual seed PPLN OPG.

    Science.gov (United States)

    Dolasinski, Brian; Powers, Peter E; Haus, Joseph W; Cooney, Adam

    2015-02-09

    We report a widely tunable narrowband terahertz (THz) source via difference frequency generation (DFG). A narrowband THz source uses the output of dual seeded periodically poled lithium niobate (PPLN) optical parametric generators (OPG) combined in the nonlinear crystal 4-dimthylamino-N-methyl-4-stilbazolium-tosylate (DAST). We demonstrate a seamlessly tunable THZ output that tunes from 1.5 THz to 27 THz with a minimum bandwidth of 3.1 GHz. The effects of dispersive phase matching, two-photon absorption, and polarization were examined and compared to a power emission model that consisted of the current accepted parameters of DAST.

  16. A high-speed tunable beam splitter for feed-forward photonic quantum information processing.

    Science.gov (United States)

    Ma, Xiao-Song; Zotter, Stefan; Tetik, Nuray; Qarry, Angie; Jennewein, Thomas; Zeilinger, Anton

    2011-11-07

    We realize quantum gates for path qubits with a high-speed, polarization-independent and tunable beam splitter. Two electro-optical modulators act in a Mach-Zehnder interferometer as high-speed phase shifters and rapidly tune its splitting ratio. We test its performance with heralded single photons, observing a polarization-independent interference contrast above 95%. The switching time is about 5.6 ns, and a maximal repetition rate is 2.5 MHz. We demonstrate tunable feed-forward operations of a single-qubit gate of path-encoded qubits and a two-qubit gate via measurement-induced interaction between two photons.

  17. Tunable Diode Laser Sensor for Monitoring and Control of Harsh Combustion Environments

    Energy Technology Data Exchange (ETDEWEB)

    VonDrasek, William; Melsio-Pubill, Anna

    2006-05-30

    This work represents the collaborative effort between American Air Liquide and Physical Sciences, Inc. for developing a sensor based on near-IR tunable diode lasers (TDL). The multi-species capability of the sensor for simultaneous monitoring of CO, O2, and H2O concentration as well as gas temperature is ideal for in-situ monitoring on industrial furnaces. The chemical species targeted are fundamental for controlling the combustion space for improved energy efficiency, reduced pollutants, and improved product quality, when coupling the measurement to a combustion control system. Several add-on modules developed provide flexibility in the system configuration for handling different process monitoring applications. For example, the on-Demand Power Control system for the 1.5 ?m laser is used for high particle density exhaust streams where laser transmission is problematic. For long-distance signal collection a fiber optic communication system is used to reduce noise pick-up. Finally, hardened modules to withstand high ambient temperatures, immune to EMF interference, protection from flying debris, and interfaced with pathlength control laser beam shielding probes were developed specifically for EAF process monitoring. Demonstration of these different system configurations was conducted on Charter Steel's reheat furnace, Imco Recycling, Inc. (now Aleris International, Inc.) aluminum reverberatory furnace, and Gerdau Ameristeel's EAF. Measurements on the reheat furnace demonstrated zone monitoring with the measurement performed close to the steel billet. Results from the aluminum furnace showed the benefit of measuring in-situ near the bath. In this case, low-level furnace optimization was performed and demonstrated 5% fuel savings. Monitoring tests on the EAF off-gas demonstrated the level of industrialization of the sensor to survive the harsh EAF environment. Long-term testing on the EAF has been on-going for over 6 months with essentially zero maintenance

  18. Cut-off scaling of high-harmonic generation driven by a femtosecond visible optical parametric amplifier

    International Nuclear Information System (INIS)

    Cirmi, Giovanni; Lai, Chien-Jen; Granados, Eduardo; Huang, Shu-Wei; Sell, Alexander; Hong, Kyung-Han; Moses, Jeffrey; Keathley, Phillip; Kärtner, Franz X

    2012-01-01

    We studied high-harmonic generation (HHG) in Ar, Ne and He gas jets using a broadly tunable, high-energy optical parametric amplifier (OPA) in the visible wavelength range. We optimized the noncollinear OPA to deliver tunable, femtosecond pulses with 200-500 µJ energy at the 1 kHz repetition rate with excellent spatiotemporal properties, suitable for HHG experiments. By tuning the central wavelength of the OPA while keeping other parameters (energy, duration and beam size) constant, we experimentally studied the scaling law of cut-off energy with the driver wavelength in helium. Our measurements show a λ 1.7+0.2 dependence of the HHG cut-off photon energy over the full visible range in agreement with previous experiments of near- and mid-IR wavelengths. By tuning the central wavelength of the driver source, the high-order harmonic spectra in the extreme ultraviolet cover the full range of photon energy between ∼25 and ∼100 eV. Due to the high coherence intrinsic in HHG, as well as the broad and continuous tunability in the extreme UV range, a high energy, high repetition rate version of this source might be an ideal seed for free electron lasers.

  19. Tunable synthesis of copper nanotubes

    International Nuclear Information System (INIS)

    Kaniukov, E; Yakimchuk, D; Kozlovsky, A; Shlimas, D; Zdorovets, M; Kadyrzhanov, K

    2016-01-01

    Simple method of tunable synthesis of copper nanotubes based on template synthesis was developed. A comprehensive study of the structural, morphological and electrical characteristics of the obtained nanostructures was carried out. Characterization of structural features was made by methods of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffractometry analysis. Evaluation of wall thickness is made by methods of gas permeability. Electrical conductivity of nanotubes was define in the study of their current-voltage characteristics. The possibility to control of copper nanotubes physical properties by variation of the deposition parameters was shown. (paper)

  20. Poly(ethylene glycol)/carbon quantum dot composite solid films exhibiting intense and tunable blue–red emission

    International Nuclear Information System (INIS)

    Hao, Yanling; Gan, Zhixing; Xu, Jiaqing; Wu, Xinglong; Chu, Paul K.

    2014-01-01

    Highlights: • Poly(ethylene glycol)/carbon quantum dots (PEG/CQDs) composite solid films exhibiting strong and tunable blue–red emission were prepared. Successful preparation of tunable emitting CQDs solid films can extend the application of carbon quantum dots in photoelectric devices. • The mechanism of the tunable emission from the PEG/CQDs composite solid films was discussed. • On the basis of the characteristics of the PL from solid films in this work, the complex PL origins of CQDs were further defined. The PL mechanism provides insights into the fluorescence mechanism of CQDs and may promotes their applications. • Poly(ethylene glycol); carbon quantum dots; Strong and tunable blue-red emission; The fluorescent quantum yield of 12.6%. - Abstract: Although carbon quantum dots (CQDs) possess excellent luminescence properties, it is a challenge to apply water-soluble CQDs to tunable luminescent devices. Herein, quaternary CQDs are incorporated into poly(ethylene glycol) to produce poly(ethylene glycol)/CQD composite solid films which exhibit strong and tunable blue–red emission. The fluorescent quantum yield reaches 12.6% which is comparable to that of many liquid CQDs and the photoluminescence characteristics are determined to elucidate the fluorescence mechanism. The CQD solid films with tunable optical properties bode well for photoelectric devices especially displays

  1. The IRS-1 signaling system.

    Science.gov (United States)

    Myers, M G; Sun, X J; White, M F

    1994-07-01

    Insulin-receptor substrate 1 (IRS-1) is a principal substrate of the receptor tyrosine kinase for insulin and insulin-like growth factor 1, and a substrate for a tyrosine kinase activated by interleukin 4. IRS-1 undergoes multisite tyrosine phosphorylation and mediates downstream signals by 'docking' various proteins that contain Src homology 2 domains. IRS-1 appears to be a unique molecule; however, 4PS, a protein found mainly in hemopoietic cells, may represent another member of this family.

  2. Study on the structure of bridge surface of the micro Fabry-Perot cavity tunable filter

    International Nuclear Information System (INIS)

    Meng Qinghua; Luo Huan; Bao Shiwei; Zhou Yifan; Chen Sihai

    2011-01-01

    Micro Fabry-Perot cavity tunable filters are widely applied in the area of Pushbroom Hyperspectral imaging, DWDM optical communication system and self-adaptive optics. With small volume, lower consumption and cost, the Micro Fabry-Perot cavity tunable filter can realize superior response speed, large spectral range, high definition and high reliability. By deposition metal membrane on silicon chip by MEMS technology, the micro Fabry-Perot cavity has been achieved, which is actuated by electrostatic force and can realize the function of an optical filter. In this paper, the micro-bridge structure of the micro Fabry-Perot cavity tunable filter has been studied. Finite element analysis software COMSOL Multiphysics has been adopted to design the structure of the micro-bridge of the micro filter. In order to simulate the working mechanism of the micro Fabry-Perot cavity and study the electrical and mechanical characteristics of the micro tunable filter,the static and dynamic characteriastics are analyzed, such as stress, displacement, transient response, etc. The corresponding parameters of the structure are considered as well by optimizition the filter's sustain structure.

  3. Optical gain tuning within IR region in type-II In0.5Ga0.5As0.8P0.2/GaAs0.5Sb0.5 nano-scale heterostructure under external uniaxial strain

    Science.gov (United States)

    Singh, A. K.; Rathi, Amit; Riyaj, Md.; Bhardwaj, Garima; Alvi, P. A.

    2017-11-01

    Quaternary and ternary alloy semiconductors offer an extra degree of flexibility in terms of bandgap tuning. Modifications in the wave functions and alterations in optical transitions in quaternary and ternary QW (quantum well) heterostructures due to external uniaxial strain provide valuable insights on the characteristics of the heterostructure. This paper reports the optical gain in strained InGaAsP/GaAsSb type-II QW heterostructure (well width = 20 Å) under external uniaxial strain at room temperature (300 K). The entire heterostructure is supposed to be grown on InP substrate pseudomorphically. Band structure, wave functions, energy dispersion and momentum matrix elements of the heterostructure have been computed. 6 × 6 diagonalised k → ·p → Hamiltonian matrix of the system is evaluated and Luttinger-Kohn model has been applied for the band structure and wavefunction calculations. TE mode optical gain spectrum in the QW-heterostructure under uniaxial strain along [110] is calculated. Optical gain of the heterostructure as a function of 2D carrier density and temperature variation is investigated. The variation of the peak optical gain as a function of As and Sb fractions in InGaAsP as a barrier and GaAsSb as a well respectively is exhibited. For a charge carrier injection of 5 ×1012 /cm2 , the TE optical gain is 3952 cm-1 at room temperature under no external uniaxial strain. Significant increase in TE mode optical gain is observed under high external uniaxial strain (1, 5 and 10 GPa) along [110] within IR (Infrared region) region.

  4. Direct phase-locking of a 8.6-μm quantum cascade laser to a mid-IR optical frequency comb: application to precision spectroscopy of N2O.

    Science.gov (United States)

    Gambetta, Alessio; Cassinerio, Marco; Coluccelli, Nicola; Fasci, Eugenio; Castrillo, Antonio; Gianfrani, Livio; Gatti, Davide; Marangoni, Marco; Laporta, Paolo; Galzerano, Gianluca

    2015-02-01

    We developed a high-precision spectroscopic system at 8.6 μm based on direct heterodyne detection and phase-locking of a room-temperature quantum-cascade-laser against an harmonic, 250-MHz mid-IR frequency comb obtained by difference-frequency generation. The ∼30  dB signal-to-noise ratio of the detected beat-note together with the achieved closed-loop locking bandwidth of ∼500  kHz allows for a residual integrated phase noise of 0.78 rad (1 Hz-5 MHz), for an ultimate resolution of ∼21  kHz, limited by the measured linewidth of the mid-IR comb. The system was used to perform absolute measurement of line-center frequencies for the rotational components of the ν2 vibrational band of N2O, with a relative precision of 3×10(-10).

  5. Tunable photonic cavities for in-situ spectroscopic trace gas detection

    Science.gov (United States)

    Bond, Tiziana; Cole, Garrett; Goddard, Lynford

    2012-11-13

    Compact tunable optical cavities are provided for in-situ NIR spectroscopy. MEMS-tunable VCSEL platforms represents a solid foundation for a new class of compact, sensitive and fiber compatible sensors for fieldable, real-time, multiplexed gas detection systems. Detection limits for gases with NIR cross-sections such as O.sub.2, CH.sub.4, CO.sub.x and NO.sub.x have been predicted to approximately span from 10.sup.ths to 10s of parts per million. Exemplary oxygen detection design and a process for 760 nm continuously tunable VCSELS is provided. This technology enables in-situ self-calibrating platforms with adaptive monitoring by exploiting Photonic FPGAs.

  6. Design of optical switches by illusion optics

    International Nuclear Information System (INIS)

    Shoorian, H R; Abrishamian, M S

    2013-01-01

    In this paper, illusion optics theory is employed to form Bragg gratings in an optical waveguide in order to design an optical switch. By using an illusion device at a certain distance from the waveguide, the effective refractive index of the waveguide is remotely modulated, turning the waveguide into a distributed Bragg reflector (DBR) which blocks the waves at a stop band. By removing the illusion device, the waves propagate through the waveguide again. In addition, this method is used to remotely tune DBR optical properties such as resonant frequency and bandwidth in a wide range, which leads to a tunable filter for optical switching applications. Finally, using an illusion device at a distance, an optical cavity is created by inserting defects remotely in a DBR without any physical damage in the primary device. (paper)

  7. Design of optical switches by illusion optics

    Science.gov (United States)

    Shoorian, H. R.; Abrishamian, M. S.

    2013-05-01

    In this paper, illusion optics theory is employed to form Bragg gratings in an optical waveguide in order to design an optical switch. By using an illusion device at a certain distance from the waveguide, the effective refractive index of the waveguide is remotely modulated, turning the waveguide into a distributed Bragg reflector (DBR) which blocks the waves at a stop band. By removing the illusion device, the waves propagate through the waveguide again. In addition, this method is used to remotely tune DBR optical properties such as resonant frequency and bandwidth in a wide range, which leads to a tunable filter for optical switching applications. Finally, using an illusion device at a distance, an optical cavity is created by inserting defects remotely in a DBR without any physical damage in the primary device.

  8. Ultra Uniform Pb0.865La0.09(Zr0.65Ti0.35O3 Thin Films with Tunable Optical Properties Fabricated via Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Shenglin Jiang

    2018-03-01

    Full Text Available Ferroelectric thin films have been utilized in a wide range of electronic and optical applications, in which their morphologies and properties can be inherently tuned by a qualitative control during growth. In this work, we demonstrate the evolution of the Pb0.865La0.09(Zr0.65Ti0.35O3 (PLZT thin films on MgO (200 with high uniformity and optimized optical property via the controls of the deposition temperatures and oxygen pressures. The perovskite phase can only be obtained at the deposition temperature above 700 °C and oxygen pressure over 50 Pa due to the improved crystallinity. Meanwhile, the surface morphologies gradually become smooth and compact owing to spontaneously increased nucleation sites with the elevated temperatures, and the crystallization of PLZT thin films also sensitively respond to the oxygen vacancies with the variation of oxygen pressures. Correspondingly, the refractive indices gradually develop with variations of the deposition temperatures and oxygen pressures resulted from the various slight loss, and the extinction coefficient for each sample is similarly near to zero due to the relatively smooth morphology. The resulting PLZT thin films exhibit the ferroelectricity, and the dielectric constant sensitively varies as a function of electric filed, which can be potentially applied in the electronic and optical applications.

  9. Generation of broadly tunable picosecond mid-infrared laser and sensitive detection of a mid-infrared signal by parametric frequency up-conversion in MgO:LiNbO3 optical parametric amplifiers

    International Nuclear Information System (INIS)

    Zhang Qiu-Lin; Zhang Jing; Qiu Kang-Sheng; Zhang Dong-Xiang; Feng Bao-Hua; Zhang Jing-Yuan

    2012-01-01

    Picosecond optical parametric generation and amplification in the near-infrared region within 1.361–1.656 μm and the mid-infrared region within 2.976–4.875 μm is constructed on the basis of bulk MgO:LiNbO 3 crystals pumped at 1.064 μm. The maximum pulse energy reaches 1.3 mJ at 1.464 μm and 0.47 mJ at 3.894 μm, corresponding to a pump-to-idler photon conversion efficiency of 25%. By seeding the hard-to-measure mid-infrared radiation as the idler in the optical parametric amplification and measuring the amplified and frequency up-converted signal in the near-infrared or even visible region, one can measure very week mid-infrared radiation with ordinary detectors, which are insensitive to mid-infrared radiation, with a very high gain. A maximum gain factor of about 7 × 10 7 is achieved at the mid-infrared wavelength of 3.374 μm and the corresponding energy detection limit is as low as about 390 aJ per pulse. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  10. Tunable emission in surface passivated Mn-ZnS nanophosphors and its application for Glucose sensing

    Directory of Open Access Journals (Sweden)

    Manoj Sharma

    2012-03-01

    Full Text Available The present work describes the tunable emission in inorganic-organic hybrid NPs which can be useful for optoelectronic and biosensing applications. In this work, Mn- ZnS nanoparticles emitting various colors, including blue and orange, were synthesized by simple chemical precipitation method using chitosan as a capping agent. Earlier reports describe that emission color characteristics in nanoparticles are tuned by varying particle size and with doping concentration. Here in this article tunable emission has been achieved by varying excitation wavelength in a single sample. This tunable emission property with high emission intensity was further achieved by changing capping concentration keeping host Mn-ZnS concentration same. Tunable emission is explained by FRET mechanism. Commission Internationale de l’Eclairage (CIE chromaticity coordinates shifts from (0.273, 0.20 and (0.344, 0.275 for same naocrystals by suitably tuning excitation energy from higher and lower ultra-violet (UV range. Synthesized nanoparticles have been characterized by X-ray diffraction, SEM, HRTEM, UV- Visible absorption and PL spectroscopy for structural and optical studies. Using tunable emission property, these highly emissive nanoparticles functionalized with biocompatible polymer chitosan were further used for glucose sensing applications.

  11. Electrically tunable photonic true-time-delay line.

    Science.gov (United States)

    Barmenkov, Yuri O; Cruz, José Luis; Díez, Antonio; Andrés, Miguel V

    2010-08-16

    We present a new application of the acousto-optic superlattice modulation of a fiber Bragg grating based on the dynamic phase and group delay properties of this fiber-optic component. We demonstrate a tunable photonic true-time-delay line based on the group delay change of the light reflected from the grating sidebands. The delay is electrically tuned by adjusting the voltage applied to a piezoelectric transducer that generates the acoustic wave propagating along the grating. In our experiments, a true-time delay of 400 ps is continuously adjusted (300 ps within the 3 dB amplitude range of the first sideband), using a 12 cm long uniform grating.

  12. Towards a petawatt-class few-cycle infrared laser system via dual-chirped optical parametric amplification.

    Science.gov (United States)

    Fu, Yuxi; Midorikawa, Katsumi; Takahashi, Eiji J

    2018-05-16

    Expansion of the wavelength range for an ultrafast laser is an important ingredient for extending its range of applications. Conventionally, optical parametric amplification (OPA) has been employed to expand the laser wavelength to the infrared (IR) region. However, the achievable pulse energy and peak power have been limited to the mJ and the GW level, respectively. A major difficulty in the further energy scaling of OPA results from a lack of suitable large nonlinear crystals. Here, we circumvent this difficulty by employing a dual-chirped optical parametric amplification (DC-OPA) scheme. We successfully generate a multi-TW IR femtosecond laser pulse with an energy of 100 mJ order, which is higher than that reported in previous works. We also obtain excellent energy scaling ability, ultrashort pulses, flexiable wavelength tunability, and high-energy stability, which prove that DC-OPA is a superior method for the energy scaling of IR pulses to the 10 J/PW level.

  13. Optics in the United kingdom.

    Science.gov (United States)

    Ditchburn, R W

    1969-10-01

    Optics is interpreted to include x-ray optics, electronic optics, and short wave radiooptics as well as the more conventional visible, uv, and ir optics. Recent work in Britain on x-ray optics (applied to molecular biology), on scanning electron microscopy, and in radioastronomy (discovery of pulsars) is mentioned. In the optics of the visible and ir there is an increasing interest in over-all systems design. .The formation of large industrial units capable of carrying through major design program, requiring advanced mechanical and electronic design associated with new lens systems, is welcomed.

  14. Semiconductor lasers with a continuous tuning range above 100 nm in the nearest IR spectral region

    Energy Technology Data Exchange (ETDEWEB)

    Kostin, Yu O; Lobintsov, A A; Shramenko, M V [OOO ' Opton' , Moscow (Russian Federation); Ladugin, M A; Marmalyuk, A A [Open Joint-Stock Company M.F. Stel' makh Polyus Research Institute, Moscow (Russian Federation); Chamorovsky, A Yu [Superlum Ltd., Unit B3, Fota Point Enterprise Park, Carrigtwohill, Co Cork (Ireland); Yakubovich, S D [Moscow State Institute of Radio-Engineering, Electronics and Automation (Technical University), Moscow (Russian Federation)

    2015-08-31

    We have developed two new types of lasers based on quantum-confined semiconductor optical amplifiers with an acousto-optic tunable filter in an external fibre ring cavity. The lasers offer continuous wavelength tuning ranges from 780 to 885 and from 880 to 1010 nm, 20 mW of cw output power, and a tuning rate up to 10{sup 4} nm s{sup -1} at an instantaneous spectral linewidth less than 0.1 nm. (lasers)

  15. Electronically tunable RC sinusoidal oscillators

    International Nuclear Information System (INIS)

    Florescu, Valeriu

    2008-01-01

    This paper presents two types of active configurations for realizing electronically tunable RC sinusoidal oscillators. The type-1 network employs two grounded scaled resistances KR 1 and KR 2 , where K is scaling factor. The frequency of oscillation W 0 is controlled conveniently by adjusting K, since W 0 appears in the form W 0 =1/K √ R 1 C 1 R 2 C 2 . For realizing the scaled resistances, an active configuration is proposed, which realizes KR 1 =R 1 /(1+f(V B )), where f(V B ) denotes a function of a controlling voltage V B . Thus the frequency tuning can be effected by controlling a voltage V B . The type-2 oscillator uses two periodically switched conductances. It is shown that the tuning of oscillation frequency can be done by varying the pulse width-to-period ratio (t/T) of the periodically switched conductances. (author)

  16. Broadband semiconductor optical amplifiers of the spectral range 750 – 1100 nm

    Energy Technology Data Exchange (ETDEWEB)

    Andreeva, E V; Il' chenko, S N; Lobintsov, A A; Shramenko, M V [Superlum Diodes Ltd., Moscow (Russian Federation); Ladugin, M A [' Sigm Plyus' Ltd, Moscow (Russian Federation); Marmalyuk, A A [Open Joint-Stock Company M.F. Stel' makh Polyus Research Institute, Moscow (Russian Federation); Yakubovich, S D [Moscow State Institute of Radio-Engineering, Electronics and Automation (Technical University), Moscow (Russian Federation)

    2013-11-30

    A line of travelling-wave semiconductor optical amplifiers (SOAs) based on heterostructures used for production of broadband superluminescent diodes is developed. The pure small-signal gains of the developed SOA modules are about 25 dB, while the gain bandwidths at a level of –10 dB reach 50 – 100 nm. As a whole, the SOA modules cover the IR spectral range from 750 to 1100 nm. The SOAs demonstrate a high reliability at a single-mode fibre-coupled cw output power up to 50 mW. Examples of application of two of the developed SOA modules as active elements of broadband fast-tunable lasers are presented. (lasers)

  17. Broadband semiconductor optical amplifiers of the spectral range 750 – 1100 nm

    International Nuclear Information System (INIS)

    Andreeva, E V; Il'chenko, S N; Lobintsov, A A; Shramenko, M V; Ladugin, M A; Marmalyuk, A A; Yakubovich, S D

    2013-01-01

    A line of travelling-wave semiconductor optical amplifiers (SOAs) based on heterostructures used for production of broadband superluminescent diodes is developed. The pure small-signal gains of the developed SOA modules are about 25 dB, while the gain bandwidths at a level of –10 dB reach 50 – 100 nm. As a whole, the SOA modules cover the IR spectral range from 750 to 1100 nm. The SOAs demonstrate a high reliability at a single-mode fibre-coupled cw output power up to 50 mW. Examples of application of two of the developed SOA modules as active elements of broadband fast-tunable lasers are presented. (lasers)

  18. Multichannel tunable omnidirectional photonic band gaps of 1D ternary photonic crystal containing magnetized cold plasma

    Science.gov (United States)

    Awasthi, Suneet Kumar; Panda, Ranjita; Chauhan, Prashant Kumar; Shiveshwari, Laxmi

    2018-05-01

    By using the transfer matrix method, theoretical investigations have been carried out in the microwave region to study the reflection properties of multichannel tunable omnidirectional photonic bandgaps (OPBGs) based on the magneto-optic Faraday effect. The proposed one dimensional ternary plasma photonic crystal consists of alternate layers of quartz, magnetized cold plasma (MCP), and air. In the absence of an external magnetic field, the proposed structure possesses two OPBGs induced by Bragg scattering and is strongly dependent on the incident angle, the polarization of the incident light, and the lattice constant unlike to the single-negative gap and zero- n ¯ gap. Next, the reflection properties of OPBGs have been made tunable by the application of external magnetic field under right hand and left hand polarization configurations. The results of this manuscript may be utilized for the development of a new kind of tunable omnidirectional band stop filter with ability to completely stop single to multiple bands (called channels) of microwave frequencies in the presence of external static magnetic field under left-hand polarization and right-hand polarization configurations, respectively. Moreover, outcomes of this study open a promising way to design tunable magneto-optical devices, omnidirectional total reflectors, and planar waveguides of high Q microcavities as a result of evanescent fields in the MCP layer to allow propagation of light.

  19. Reconfigurable optical-to-optical frequency conversion method and apparatus

    Science.gov (United States)

    Zortman, William A.; Lentine, Anthony L.

    2017-04-18

    A photonic device is provided for impressing a modulation pattern on an optical carrier. The device includes a unit in which a photodetector and an optical microresonator are monolithically integrated. The device further includes an optical waveguide evanescently coupled to the optical microresonator and having at least an upstream portion configured to carry at least one optical carrier toward the microresonator. The optical microresonator is tunable so as to resonate with the optical carrier frequency. The optical microresonator and the photodetector are mutually coupled such that in operation, charge carriers photogenerated in the photodetector are injected into the microresonator, where the photocurrent changes the resonant conditions. In some embodiments the device is operable as an optical-to-optical frequency converter. In other embodiments the device is operable as an oscillator.

  20. Experimental demonstration of water based tunable metasurface

    DEFF Research Database (Denmark)

    Odit, Mikhail; Kapitanova, Polina; Andryieuski, Andrei

    2016-01-01

    A simple dynamically tunable metasurface (two-dimensional metamaterial) operating at microwave frequencies is developed and experimentally investigated. Conceptually, the simplicity of the approach is granted by reconfigurable properties of unit cells partially filled with distilled water...