RIR-MAPLE deposition of conjugated polymers and hybrid nanocomposites for application to optoelectronic devices

International Nuclear Information System (INIS)

Stiff-Roberts, Adrienne D.; Pate, Ryan; McCormick, Ryan; Lantz, Kevin R.

2012-01-01

Resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) is a variation of pulsed laser deposition that is useful for organic-based thin films because it reduces material degradation by selective absorption of infrared radiation in the host matrix. A unique emulsion-based RIR-MAPLE approach has been developed that reduces substrate exposure to solvents and provides controlled and repeatable organic thin film deposition. In order to establish emulsion-based RIR-MAPLE as a preferred deposition technique for conjugated polymer or hybrid nanocomposite optoelectronic devices, studies have been conducted to demonstrate the value added by the approach in comparison to traditional solution-based deposition techniques, and this work will be reviewed. The control of hybrid nanocomposite thin film deposition, and the photoconductivity in such materials deposited using emulsion-based RIR-MAPLE, will also be reviewed. The overall result of these studies is the demonstration of emulsion-based RIR-MAPLE as a viable option for the fabrication of conjugated polymer and hybrid nanocomposite optoelectronic devices that could yield improved device performance.

Impurities in semiconductors: total energy and infrared absorption calculations

International Nuclear Information System (INIS)

Yndurain, F.

1987-01-01

A new method to calculate the electronic structure of infinite nonperiodic system is discussed. The calculations are performed using atomic pseudopotentials and a basis of atomic Gaussiam wave functions. The Hartree-Fock self consistent equations are solved in the cluster-Bethe lattice system. Electron correlation is partially included in second order pertubation approximation. The formalism is applied to hydrogenated amorphous silicon. Total energy calculations of finite clusters of silicon atom in the presence of impurities, are also presented. The results show how atomic oxygen breaks the covalent silicon silicon bond forming a local configuration similar to that of SiO 2 . Calculations of the infrared absorption due to the presence of atomic oxygen in cristalline silicon are presented. The Born Hamiltonian to calculate the vibrational modes of the system and a simplied model to describe the infrared absorption mechanism are used. The interstitial and the the substitutional cases are considered and analysed. The position of the main infrared absorption peak, their intensities and their isotope shifts are calculated. The results are satisfactory agreement with the available data. (author) [pt

High-efficient light absorption of monolayer graphene via cylindrical dielectric arrays and the sensing application

Science.gov (United States)

Zhou, Peng; Zheng, Gaige

2018-04-01

The efficiency of graphene-based optoelectronic devices is typically limited by the poor absolute absorption of light. A hybrid structure of monolayer graphene with cylindrical titanium dioxide (TiO2) array and aluminum oxide (Al2O3) spacer layer on aluminum (Al) substrate has been proposed to enhance the absorption for two-dimensional (2D) materials. By combining dielectric array with metal substrate, the structure achieves multiple absorption peaks with near unity absorbance at near-infrared wavelengths due to the resonant effect of dielectric array. Completed monolayer graphene is utilized in the design without any demand of manufacture process to form the periodic patterns. Further analysis indicates that the near-field enhancement induced by surface modes gives rise to the high absorption. This favorable field enhancement and tunability of absorption not only open up new approaches to accelerate the light-graphene interaction, but also show great potential for practical applications in high-performance optoelectronic devices, such as modulators and sensors.

Far-Infrared Absorption of PbSe Nanorods

KAUST Repository

Hyun, Byung-Ryool; Bartnik, A. C.; Koh, Weon-kyu; Agladze, N. I.; Wrubel, J. P.; Sievers, A. J.; Murray, Christopher B.; Wise, Frank W.

2011-01-01

Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical

Metal Complexes for Organic Optoelectronic Applications

Science.gov (United States)

Huang, Liang

Organic optoelectronic devices have drawn extensive attention by over the past two decades. Two major applications for Organic optoelectronic devices are efficient organic photovoltaic devices(OPV) and organic light emitting diodes (OLED). Organic Solar cell has been proven to be compatible with the low cost, large area bulk processing technology and processed high absorption efficiencies compared to inorganic solar cells. Organic light emitting diodes are a promising approach for display and solid state lighting applications. To improve the efficiency, stability, and materials variety for organic optoelectronic devices, several emissive materials, absorber-type materials, and charge transporting materials were developed and employed in various device settings. Optical, electrical, and photophysical studies of the organic materials and their corresponding devices were thoroughly carried out. In this thesis, Chapter 1 provides an introduction to the background knowledge of OPV and OLED research fields presented. Chapter 2 discusses new porphyrin derivatives- azatetrabenzylporphyrins for OPV and near infrared OLED applications. A modified synthetic method is utilized to increase the reaction yield of the azatetrabenzylporphyrin materials and their photophysical properties, electrochemical properties are studied. OPV devices are also fabricated using Zinc azatetrabenzylporphyrin as donor materials. Pt(II) azatetrabenzylporphyrin were also synthesized and used in near infra-red OLED to achieve an emission over 800 nm with reasonable external quantum efficiencies. Chapter 3, discusses the synthesis, characterization, and device evaluation of a series of tetradentate platinum and palladium complexesfor single doped white OLED applications and RGB white OLED applications. Devices employing some of the developed emitters demonstrated impressively high external quantum efficiencies within the range of 22%-27% for various emitter concentrations. And the palladium complex, i

The use of infrared absorption to determine density of liquid hydrogen.

Science.gov (United States)

Unland, H. D.; Timmerhaus, K. D.; Kropschot, R. H.

1972-01-01

Experimental evaluation of the use of infrared absorption for determining the density of liquid hydrogen, and discussion of the feasibility of an airborne densitometer based on this concept. The results indicate that infrared absorption of liquid hydrogen is highly sensitive to the density of hydrogen, and, under the operating limitations of the equipment and experimental techniques used, the determined values proved to be repeatable to an accuracy of 2.7%. The desiderata and limitations of an in-flight density-determining device are outlined, and some of the feasibility problems are defined.

Silicon oxide particle formation in RF plasmas investigated by infrared absorption spectroscopy and mass spectrometry

NARCIS (Netherlands)

Hollenstein, Ch.; Howling, A.A.; Courteille, C.; Magni, D.; Scholz, S.M.; Kroesen, G.M.W.; Simons, N.; de Zeeuw, W.; Schwarzenbach, W.

1998-01-01

In situ Fourier transform infrared absorption spectroscopy has been used to study the composition of particles formed and suspended in radio-frequency discharges of silane - oxygen-argon gas mixtures. The silane gas consumption was observed by infrared absorption. The stoichiometry of the produced

Infra-red absorption in rare-gas mixtures

International Nuclear Information System (INIS)

Weiss, S.

1980-01-01

Infrared absorption in rare-gas mixtures has been studied extensively, so that by now the spectra at room temperature of almost all pairs are available. Turning attention first to the gas phase, it is shown that the considerable mass of experimental results can be reduced to yield a relatively simple picture. Having reviewed the experimental facts, the interpretation and extraction of information is discussed. (KBE)

Infrared multiphoton absorption and decomposition

International Nuclear Information System (INIS)

Evans, D.K.; McAlpine, R.D.

1984-01-01

The discovery of infrared laser induced multiphoton absorption (IRMPA) and decomposition (IRMPD) by Isenor and Richardson in 1971 generated a great deal of interest in these phenomena. This interest was increased with the discovery by Ambartzumian, Letokhov, Ryadbov and Chekalin that isotopically selective IRMPD was possible. One of the first speculations about these phenomena was that it might be possible to excite a particular mode of a molecule with the intense infrared laser beam and cause decomposition or chemical reaction by channels which do not predominate thermally, thus providing new synthetic routes for complex chemicals. The potential applications to isotope separation and novel chemistry stimulated efforts to understand the underlying physics and chemistry of these processes. At ICOMP I, in 1977 and at ICOMP II in 1980, several authors reviewed the current understandings of IRMPA and IRMPD as well as the particular aspect of isotope separation. There continues to be a great deal of effort into understanding IRMPA and IRMPD and we will briefly review some aspects of these efforts with particular emphasis on progress since ICOMP II. 31 references

Infrared Absorption Spectroscopy and Chemical Kinetics of Free Radicals. Final Performance Report, August 1, 1985--July 31, 1994

Science.gov (United States)

Curl, R. F.; Glass, G. P.

1995-06-01

This research was directed at the detection, monitoring, and study (by infrared absorption spectroscopy) of the chemical kinetic behavior of small free radical species thought to be important intermediates in combustion. The work typically progressed from the detection and analysis of the infrared spectrum of combustion radical to the utilization of the infrared spectrum thus obtained in the investigation of chemical kinetics of the radical species. The methodology employed was infrared kinetic spectroscopy. In this technique the radical is produced by UV flash photolysis using an excimer laser and then its transient infrared absorption is observed using a single frequency cw laser as the source of the infrared probe light. When the probe laser frequency is near the center of an absorption line of the radical produced by the flash, the transient infrared absorption rises rapidly and then decays as the radical reacts with the precursor or with substances introduced for the purpose of studying the reaction kinetics or with itself. The decay times observed in these studies varied from less than one microsecond to more than one millisecond. By choosing appropriate time windows after the flash and the average infrared detector signal in a window as data channels, the infrared spectrum of the radical may be obtained. By locking the infrared probe laser to the center of the absorption line and measuring the rate of decay of the transient infrared absorption signal as the chemical composition of the gas mixture is varied, the chemical kinetics of the radical may be investigated. In what follows the systems investigated and the results obtained are outlined.

Infrared absorption studies of the annealing of irradiated diamonds

International Nuclear Information System (INIS)

Woods, G.S.

1984-01-01

Natural (types Ia and IIa) and synthetic (type Ib) diamonds have been irradiated with energetic electrons and neutrons and then heated at temperatures up to 1400 deg C. Attendant changes in the infrared absorption spectra, especially above the Raman frequency (1332 cm -1 ), have been monitored. The most prominent absorption to develop in the infrared region proper, on annealing both type Ia and type Ib specimens, whether electron- or neutron-irradiated is the H1a line at 1450 cm -1 . Measurements taken of neutron-irradiated type Ia specimens show that the strength of this line is specimen-dependent, and that it is a linear function of radiation dose. Isochronal annealing studies show that the onset of the line occurs during heating at 250 deg C for type Ia specimens and at 650 deg C for type Ib specimens. The absorption begins to weaken during heating at 1100 deg C, but it is very persistent, surviving an anneal of 4 hours at 1400 deg C, albeit with diminished intensity. Three other weaker lines at 1438, 1358 and 1355 cm -1 develop with the 1450 cm -1 line, but differ from it and from each other in subsequent annealing behaviour. Other lines were observed; these are reported and discussed. (author)

Near-infrared light absorption by polycrystalline SiSn alloys grown on insulating layers

Energy Technology Data Exchange (ETDEWEB)

Kurosawa, Masashi, E-mail: kurosawa@alice.xtal.nagoya-u.ac.jp [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); JSPS, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Kato, Motohiro; Yamaha, Takashi; Taoka, Noriyuki; Nakatsuka, Osamu [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Zaima, Shigeaki [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2015-04-27

High-Sn-content SiSn alloys are strongly desired for the next-generation near-infrared optoelectronics. A polycrystalline growth study has been conducted on amorphous SiSn layers with a Sn-content of 2%–30% deposited on either a substrate of SiO{sub 2} or SiN. Incorporating 30% Sn into Si permits the crystallization of the amorphous layers at annealing temperatures below the melting point of Sn (231.9 °C). Composition analyses indicate that approximately 20% of the Sn atoms are substituted into the Si lattice after solid-phase crystallization at 150–220 °C for 5 h. Correspondingly, the optical absorption edge is red-shifted from 1.12 eV (Si) to 0.83 eV (Si{sub 1−x}Sn{sub x} (x ≈ 0.18 ± 0.04)), and the difference between the indirect and direct band gap is significantly reduced from 3.1 eV (Si) to 0.22 eV (Si{sub 1−x}Sn{sub x} (x ≈ 0.18 ± 0.04)). These results suggest that with higher substitutional Sn content the SiSn alloys could become a direct band-gap material, which would provide benefits for Si photonics.

Infrared Absorption by Atmospheric Aerosols in Mexico City during MILAGRO.

Science.gov (United States)

Kelley, K. L.; Mangu, A.; Gaffney, J. S.; Marley, N. A.

2007-12-01

Past research in our group using cylindrical internal reflectance spectroscopy has indicated that aqueous aerosols could contribute to the radiative warming as greenhouse species (1,2). Although aerosol radiative effects have been known for sometime and are considered one of the major uncertainties in climate change modeling, most of the studies have focused on the forcing due to scattering and absorption of radiation in the uv- visible region (3). Infrared spectral information also allows the confirmation of key functional groups that are responsible for enhanced absorption observations from secondary organics in the uv-visible region. This work extends our efforts to evaluate the infrared absorption by aerosols, particularly organics, that are now found to be a major fraction of urban and regional aerosols in the 0.1 to 1.0 micron size range and to help identify key types of organics that can contribute to aerosol absorption. During the MILAGRO campaign, quartz filter samples were taken at 12-hour intervals from 5 am to 5 pm (day) and from 5 pm to 5 am (night) during the month of March 2006. These samples were taken at the two super-sites, T-0 (Instituto Mexicano de Petroleo in Mexico City) and T-1 (Universidad Technologica de Tecamac, State of Mexico). The samples have been characterized for total carbon content (stable isotope mass spectroscopy) and natural radionuclide tracers, as well as for their UV-visible spectroscopic properties by using integrating sphere diffuse reflectance spectroscopy (Beckman DU with a Labsphere accessory). These same samples have been characterized in the mid and near infrared spectral ranges using diffuse reflection spectroscopy (Nicolet 6700 FTIR with a Smart Collector accessory). Aerosol samples were removed from the surfaces of the aerosol filters by using Si-Carb sampler. The samples clearly indicate the presence of carbonyl organic constituents and the spectra are quite similar to those observed for humic and fulvic acids

Integrated graphene-based devices for optoelectronic applications

DEFF Research Database (Denmark)

Xiao, Sanshui

Graphene opens up for novel optoelectronic applications thanks to its high carrier mobility, ultralarge absorption bandwidth, and extremely fast material response. Here I present novel integrated grapheneplasmonic waveguide modulator showing high modulation depth, thus giving a promising way...

Infrared absorption spectroscopy and chemical kinetics of free radicals

Energy Technology Data Exchange (ETDEWEB)

Curl, R.F.; Glass, G.P. [Rice Univ., Houston, TX (United States)

1993-12-01

This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

Insulating materials for optoelectronics

International Nuclear Information System (INIS)

Agullo-Lopez, F.

1990-01-01

Optoelectronics is an interdisciplinary field. Basic functions of an optoelectronic system include the generator of the optical signal, its transmission and handling and, finally, its detection, storage and display. A large variety of semiconductor and insulating materials are used or are being considered to perform those functions. The authors focus on insulating materials, mostly oxides. For signal generation, tunable solid state lasers, either vibronic or those based oon colour centres are briefly described, and their main operating parameters summarized. Reference is made to some developments on fiber and waveguide lasers. Relevant physical features of the silica fibres used for low-loss, long-band, optical transmission are reviewed, as well as present efforts to further reduce attenuation in the mid-infrared range. Particular attention is paid to photorefractive materials (LiNbO 3 , BGO, BSO, etc.), which are being investigated

Femtosecond laser irradiation-induced infrared absorption on silicon surfaces

Directory of Open Access Journals (Sweden)

Qinghua Zhu

2015-04-01

Full Text Available The near-infrared (NIR absorption below band gap energy of crystalline silicon is significantly increased after the silicon is irradiated with femtosecond laser pulses at a simple experimental condition. The absorption increase in the NIR range primarily depends on the femtosecond laser pulse energy, pulse number, and pulse duration. The Raman spectroscopy analysis shows that after the laser irradiation, the silicon surface consists of silicon nanostructure and amorphous silicon. The femtosecond laser irradiation leads to the formation of a composite of nanocrystalline, amorphous, and the crystal silicon substrate surface with microstructures. The composite has an optical absorption enhancement at visible wavelengths as well as at NIR wavelength. The composite may be useful for an NIR detector, for example, for gas sensing because of its large surface area.

Collision-Induced Infrared Absorption by Hydrogen-Helium gas mixtures at Thousands of Kelvin

Science.gov (United States)

Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

2010-10-01

The interaction-induced absorption by collisional pairs of H2 molecules is an important opacity source in the atmospheres of the outer planets and cool stars ^[1]. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H2--H2, H2--He, and H2--H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin ^[2]. Laboratory measurements of interaction-induced absorption spectra by H2 pairs exist only at room temperature and below. We show that our results reproduce these measurements closely ^[2], so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures ^[2]. [1] L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 [2] Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, ``Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin'', International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201

Far-Infrared Absorption of PbSe Nanorods

KAUST Repository

Hyun, Byung-Ryool

2011-07-13

Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical electrostatic model, which is based on the dielectric function of bulk PbSe but without any free-carrier contribution. Good agreement between the measured and calculated spectra indicates that resonances in the local field factors underlie the measured spectra. © 2011 American Chemical Society.

FDTD/TDSE study of surface-enhanced infrared absorption by metal nanoparticles.

Energy Technology Data Exchange (ETDEWEB)

Chang, S.-H.; Schatz, G. C.; Gray, S. K.; Chemistry; Northwestern Univ.; National Cheng-Kung Univ.

2006-01-01

We study surface-enhanced infrared absorption, including multiphoton processes, due to the excitation of surface plasmons on metal nanoparticles. The time-dependent Schroedinger equation and finite-difference time-domain method are self-consistently coupled to treat the problem.

Transient Infrared Measurement of Laser Absorption Properties of Porous Materials

Directory of Open Access Journals (Sweden)

Marynowicz Andrzej

2016-06-01

Full Text Available The infrared thermography measurements of porous building materials have become more frequent in recent years. Many accompanying techniques for the thermal field generation have been developed, including one based on laser radiation. This work presents a simple optimization technique for estimation of the laser beam absorption for selected porous building materials, namely clinker brick and cement mortar. The transient temperature measurements were performed with the use of infrared camera during laser-induced heating-up of the samples’ surfaces. As the results, the absorbed fractions of the incident laser beam together with its shape parameter are reported.

Transient Infrared Measurement of Laser Absorption Properties of Porous Materials

Science.gov (United States)

Marynowicz, Andrzej

2016-06-01

The infrared thermography measurements of porous building materials have become more frequent in recent years. Many accompanying techniques for the thermal field generation have been developed, including one based on laser radiation. This work presents a simple optimization technique for estimation of the laser beam absorption for selected porous building materials, namely clinker brick and cement mortar. The transient temperature measurements were performed with the use of infrared camera during laser-induced heating-up of the samples' surfaces. As the results, the absorbed fractions of the incident laser beam together with its shape parameter are reported.

Broadband and wide angle near-unity absorption in graphene-insulator-metal thin film stacks

Science.gov (United States)

Zhang, H. J.; Zheng, G. G.; Chen, Y. Y.; Xu, L. H.

2018-05-01

Broadband unity absorption in graphene-insulator-metal (GIM) structures is demonstrated in the visible (VIS) and near-infrared (NIR) spectra. The spectral characteristics possess broadband absorption peaks, by simply choosing a stack of GIM, while no nanofabrication steps and patterning are required, and thus can be easily fabricated to cover a large area. The electromagnetic (EM) waves can be entirely trapped and the absorption can be greatly enhanced are verified with the finite-difference time-domain (FDTD) and rigorous coupled wave analysis (RCWA) methods. The position and the number of the absorption peak can be totally controlled by adjusting the thickness of the insulator layer. The proposed absorber maintains high absorption (above 90%) for both transverse electric (TE) and transverse magnetic (TM) polarizations, and for angles of incidence up to 80°. This work opens up a promising approach to realize perfect absorption (PA) with ultra-thin film, which could implicate many potential applications in optical detection and optoelectronic devices.

Quantum dot optoelectronic devices: lasers, photodetectors and solar cells

International Nuclear Information System (INIS)

Wu, Jiang; Chen, Siming; Seeds, Alwyn; Liu, Huiyun

2015-01-01

Nanometre-scale semiconductor devices have been envisioned as next-generation technologies with high integration and functionality. Quantum dots, or the so-called ‘artificial atoms’, exhibit unique properties due to their quantum confinement in all 3D. These unique properties have brought to light the great potential of quantum dots in optoelectronic applications. Numerous efforts worldwide have been devoted to these promising nanomaterials for next-generation optoelectronic devices, such as lasers, photodetectors, amplifiers, and solar cells, with the emphasis on improving performance and functionality. Through the development in optoelectronic devices based on quantum dots over the last two decades, quantum dot devices with exceptional performance surpassing previous devices are evidenced. This review describes recent developments in quantum dot optoelectronic devices over the last few years. The paper will highlight the major progress made in 1.3 μm quantum dot lasers, quantum dot infrared photodetectors, and quantum dot solar cells. (topical review)

Monolithic optoelectronic integrated broadband optical receiver with graphene photodetectors

Directory of Open Access Journals (Sweden)

Cheng Chuantong

2017-07-01

Full Text Available Optical receivers with potentially high operation bandwidth and low cost have received considerable interest due to rapidly growing data traffic and potential Tb/s optical interconnect requirements. Experimental realization of 65 GHz optical signal detection and 262 GHz intrinsic operation speed reveals the significance role of graphene photodetectors (PDs in optical interconnect domains. In this work, a novel complementary metal oxide semiconductor post-backend process has been developed for integrating graphene PDs onto silicon integrated circuit chips. A prototype monolithic optoelectronic integrated optical receiver has been successfully demonstrated for the first time. Moreover, this is a firstly reported broadband optical receiver benefiting from natural broadband light absorption features of graphene material. This work is a perfect exhibition of the concept of monolithic optoelectronic integration and will pave way to monolithically integrated graphene optoelectronic devices with silicon ICs for three-dimensional optoelectronic integrated circuit chips.

Monolithic optoelectronic integrated broadband optical receiver with graphene photodetectors

Science.gov (United States)

Cheng, Chuantong; Huang, Beiju; Mao, Xurui; Zhang, Zanyun; Zhang, Zan; Geng, Zhaoxin; Xue, Ping; Chen, Hongda

2017-07-01

Optical receivers with potentially high operation bandwidth and low cost have received considerable interest due to rapidly growing data traffic and potential Tb/s optical interconnect requirements. Experimental realization of 65 GHz optical signal detection and 262 GHz intrinsic operation speed reveals the significance role of graphene photodetectors (PDs) in optical interconnect domains. In this work, a novel complementary metal oxide semiconductor post-backend process has been developed for integrating graphene PDs onto silicon integrated circuit chips. A prototype monolithic optoelectronic integrated optical receiver has been successfully demonstrated for the first time. Moreover, this is a firstly reported broadband optical receiver benefiting from natural broadband light absorption features of graphene material. This work is a perfect exhibition of the concept of monolithic optoelectronic integration and will pave way to monolithically integrated graphene optoelectronic devices with silicon ICs for three-dimensional optoelectronic integrated circuit chips.

Recommendations for the presentation of infrared absorption spectra in data collections condensed phases

CERN Document Server

Becker, E D

2013-01-01

Recommendations for the Presentation of Infrared Absorption Spectra in Data Collections-A. Condensed Phases presents the recommendations related to the infrared spectra of condensed phase materials that are proposed for permanent retention in data collections. These recommendations are based on two reports published by the Coblentz Society. This book emphasizes the three levels of quality evaluation for infrared spectra as designated by the Coblentz Society, including critically defined physical data, research quality analytical spectra, and approved analytical spectra. This text discusses the

Optoelectronic Properties of Van Der Waals Hybrid Structures: Fullerenes on Graphene Nanoribbons.

Science.gov (United States)

Correa, Julián David; Orellana, Pedro Alejandro; Pacheco, Mónica

2017-03-20

The search for new optical materials capable of absorbing light in the frequency range from visible to near infrared is of great importance for applications in optoelectronic devices. In this paper, we report a theoretical study of the electronic and optical properties of hybrid structures composed of fullerenes adsorbed on graphene and on graphene nanoribbons. The calculations are performed in the framework of the density functional theory including the van der Waals dispersive interactions. We found that the adsorption of the C 60 fullerenes on a graphene layer does not modify its low energy states, but it has strong consequences for its optical spectrum, introducing new absorption peaks in the visible energy region. The optical absorption of fullerenes and graphene nanoribbon composites shows a strong dependence on photon polarization and geometrical characteristics of the hybrid systems, covering a broad range of energies. We show that an external electric field across the nanoribbon edges can be used to tune different optical transitions coming from nanoribbon-fullerene hybridized states, which yields a very rich electro-absorption spectrum for longitudinally polarized photons. We have carried out a qualitative analysis on the potential of these hybrids as possible donor-acceptor systems in photovoltaic cells.

Optoelectronic Properties of Van Der Waals Hybrid Structures: Fullerenes on Graphene Nanoribbons

Directory of Open Access Journals (Sweden)

Julián David Correa

2017-03-01

Full Text Available The search for new optical materials capable of absorbing light in the frequency range from visible to near infrared is of great importance for applications in optoelectronic devices. In this paper, we report a theoretical study of the electronic and optical properties of hybrid structures composed of fullerenes adsorbed on graphene and on graphene nanoribbons. The calculations are performed in the framework of the density functional theory including the van der Waals dispersive interactions. We found that the adsorption of the C 60 fullerenes on a graphene layer does not modify its low energy states, but it has strong consequences for its optical spectrum, introducing new absorption peaks in the visible energy region. The optical absorption of fullerenes and graphene nanoribbon composites shows a strong dependence on photon polarization and geometrical characteristics of the hybrid systems, covering a broad range of energies. We show that an external electric field across the nanoribbon edges can be used to tune different optical transitions coming from nanoribbon–fullerene hybridized states, which yields a very rich electro-absorption spectrum for longitudinally polarized photons. We have carried out a qualitative analysis on the potential of these hybrids as possible donor-acceptor systems in photovoltaic cells.

Broadband infrared absorption enhancement by electroless-deposited silver nanoparticles

Directory of Open Access Journals (Sweden)

Gritti Claudia

2016-07-01

Full Text Available Decorating semiconductor surfaces with plasmonic nanoparticles (NPs is considered a viable solution for enhancing the absorptive properties of photovoltaic and photodetecting devices. We propose to deposit silver NPs on top of a semiconductor wafer by a cheap and fast electroless plating technique. Optical characterization confirms that the random array of electroless-deposited NPs improves absorption by up to 20% in a broadband of near-infrared frequencies from the bandgap edge to 2000 nm. Due to the small filling fraction of particles, the reflection in the visible range is practically unchanged, which points to the possible applications of such deposition method for harvesting photons in nanophotonics and photovoltaics. The broadband absorption is a consequence of the resonant behavior of particles with different shapes and sizes, which strongly localize the incident light at the interface of a high-index semiconductor substrate. Our hypothesis is substantiated by examining the plasmonic response of the electroless-deposited NPs using both electron energy loss spectroscopy and numerical calculations.

Conformational aspects of proteins at the air/water interface studied by infrared reflection-absorption spectroscopy

NARCIS (Netherlands)

Martin, A.H.; Meinders, M.B.J.; Bos, M.A.; Cohen Stuart, M.A.; Vliet, T. van

2003-01-01

From absorption spectra obtained with infrared reflection - absorption spectroscopy (IRRAS), it is possible to obtain information on conformational changes at a secondary folding level of proteins adsorbed at the air/water interface. In addition, information on protein concentration at the interface

A new and fast in-situ spectroscopic infrared absorption measurement technique

NARCIS (Netherlands)

Hest, van M.F.A.M.; Klaver, A.; Sanden, van de M.C.M.

2001-01-01

Silicon oxide like films are deposited using an expanding thermal plasma (cascaded arc) in combination with HMDSO and oxygen as deposition precursors. These films are deposited at high rate (up to 200 nm/s). In general Fourier transform infrared (FTIR) reflection absorption spectroscopy is a useful

Largely Improved Near-Infrared Silicon-Photosensing by the Piezo-Phototronic Effect.

Science.gov (United States)

Dai, Yejing; Wang, Xingfu; Peng, Wenbo; Zou, Haiyang; Yu, Ruomeng; Ding, Yong; Wu, Changsheng; Wang, Zhong Lin

2017-07-25

Although silicon (Si) devices are the backbone of modern (opto-)electronics, infrared Si-photosensing suffers from low-efficiency due to its limitation in light-absorption. Here, we demonstrate a large improvement in the performance, equivalent to a 366-fold enhancement in photoresponsivity, of a Si-based near-infrared (NIR) photodetector (PD) by introducing the piezo-phototronic effect via a deposited CdS layer. By externally applying a -0.15‰ compressive strain to the heterojunction, carrier-dynamics modulation at the local junction can be induced by the piezoelectric polarization, and the photoresponsivity and detectivity of the PD exhibit an enhancement of two orders of magnitude, with the peak values up to 19.4 A/W and 1.8 × 10 12 cm Hz 1/2 /W, respectively. The obtained maximum responsivity is considerably larger than those of commercial Si and InGaAs PDs in the NIR waveband. Meanwhile, the rise time and fall time are reduced by 84.6% and 76.1% under the external compressive strain. This work provides a cost-effective approach to achieve high-performance NIR photosensing by the piezo-phototronic effect for high-integration Si-based optoelectronic systems.

Absorption Spectroscopy in Hollow-Glass Waveguides Using Infrared Diode Lasers[4817-25

International Nuclear Information System (INIS)

Blake, Thomas A.; Kelly, James F.; Stewart, Timothy L.; Hartman, John S.; Sharpe, Steven W.; Sams, Robert L.; Alan Fried

2002-01-01

Near- and mid-infrared diode lasers combined with flexible, hollow waveguides hold the promise of light weight, field portable, fast response gas sensors. The advantages of using the waveguides compared to White or Herriott multireflection cells include a small gas volume, a high photon fill factor in the waveguide, which increases molecule-light interactions, and reduction or elimination of optical fringing, which usually sets the practical limit of detectivity in absorption spectroscopy. Though hollow waveguides have been commercially available for several years, relatively few results have been reported in the literature. We present here results from our laboratory where we have injected infrared laser light into straight and coiled lengths of hollow waveguides and performed direct and wavelength modulated absorption spectroscopy on nitrous oxide, ethylene, and nitric oxide. Using a 1 mm bore, 3 meter long coiled waveguide coated for the near infrared, nitrous oxide transitions near 6595 cm-1 were observed under flowing conditions. Signal-to-noise ratios on the order of 1500:1 with RMS noise equal to 2 X 10-5 were measured. In the mid-infrared light from either a 10.1 or 5.3 micron lead salt diode laser was injected into a three meter length of 1 mm bore hollow waveguide coated for the mid-infrared. The waveguide was coiled with one loop at a diameter of 52 cm. Ethylene transitions were observed in the vicinity of 985 cm-1 with a static fill of 0.2 Torr of pure ethylene in the waveguide and nitric oxide transitions were observed in the vicinity of 1906 cm-1 using either a flow or a static fill of 1 ppm NO in nitrogen. In direct absorption the NO transitions are observed to have a signal-to-noise of approximately 5:1 for transitions with absorbances on the order of 10-3. Using wavelength modulated techniques the signal-to-noise ratio improves at least an order of magnitude. These encouraging results indicate that waveguides can be used for in situ gas monitoring

A Group Increment Scheme for Infrared Absorption Intensities of Greenhouse Gases

Science.gov (United States)

Kokkila, Sara I.; Bera, Partha P.; Francisco, Joseph S.; Lee, Timothy J.

2012-01-01

A molecule's absorption in the atmospheric infrared (IR) window (IRW) is an indicator of its efficiency as a greenhouse gas. A model for estimating the absorption of a fluorinated molecule within the IRW was developed to assess its radiative impact. This model will be useful in comparing different hydrofluorocarbons and hydrofluoroethers contribution to global warming. The absorption of radiation by greenhouse gases, in particular hydrofluoroethers and hydrofluorocarbons, was investigated using ab initio quantum mechanical methods. Least squares regression techniques were used to create a model based on this data. The placement and number of fluorines in the molecule were found to affect the absorption in the IR window and were incorporated into the model. Several group increment models are discussed. An additive model based on one-carbon groups is found to work satisfactorily in predicting the ab initio calculated vibrational intensities.

Exceptional Optoelectronic Properties of Hydrogenated Bilayer Silicene

Directory of Open Access Journals (Sweden)

Bing Huang

2014-05-01

Full Text Available Silicon is arguably the best electronic material, but it is not a good optoelectronic material. By employing first-principles calculations and the cluster-expansion approach, we discover that hydrogenated bilayer silicene (BS shows promising potential as a new kind of optoelectronic material. Most significantly, hydrogenation converts the intrinsic BS, a strongly indirect semiconductor, into a direct-gap semiconductor with a widely tunable band gap. At low hydrogen concentrations, four ground states of single- and double-sided hydrogenated BS are characterized by dipole-allowed direct (or quasidirect band gaps in the desirable range from 1 to 1.5 eV, suitable for solar applications. At high hydrogen concentrations, three well-ordered double-sided hydrogenated BS structures exhibit direct (or quasidirect band gaps in the color range of red, green, and blue, affording white light-emitting diodes. Our findings open opportunities to search for new silicon-based light-absorption and light-emitting materials for earth-abundant, high-efficiency, optoelectronic applications.

Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Chen Li [Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen (Germany); Ueta, Hirokazu; Beck, Rainer D. [Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne (Switzerland); Bisson, Regis [Aix-Marseille Universite, PIIM, CNRS, UMR 7345, 13397 Marseille (France)

2013-05-15

We report the design and characterization of a new molecular-beam/surface-science apparatus for quantum state-resolved studies of gas/surface reaction dynamics combining optical state-specific reactant preparation in a molecular beam by rapid adiabatic passage with detection of surface-bound reaction products by reflection absorption infrared spectroscopy (RAIRS). RAIRS is a non-invasive infrared spectroscopic detection technique that enables online monitoring of the buildup of reaction products on the target surface during reactant deposition by a molecular beam. The product uptake rate obtained by calibrated RAIRS detection yields the coverage dependent state-resolved reaction probability S({theta}). Furthermore, the infrared absorption spectra of the adsorbed products obtained by the RAIRS technique provide structural information, which help to identify nascent reaction products, investigate reaction pathways, and determine branching ratios for different pathways of a chemisorption reaction. Measurements of the dissociative chemisorption of methane on Pt(111) with this new apparatus are presented to illustrate the utility of RAIRS detection for highly detailed studies of chemical reactions at the gas/surface interface.

Inapplicability of small-polaron model for the explanation of infrared absorption spectrum in acetanilide.

Science.gov (United States)

Zeković, Slobodan; Ivić, Zoran

2009-01-01

The applicability of small-polaron model for the interpretation of infrared absorption spectrum in acetanilide has been critically reexamined. It is shown that the energy difference between the normal and anomalous peak, calculated by means of small-polaron theory, displays pronounced temperature dependence which is in drastic contradiction with experiment. It is demonstrated that self-trapped states, which are recently suggested to explain theoretically the experimental absorption spectrum in protein, cannot cause the appearance of the peaks in absorption spectrum for acetanilide.

Collision-Induced Infrared Absorption by Collisional Complexes in Dense Hydrogen-Helium Gas Mixtures at Thousands of Kelvin

Science.gov (United States)

Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

2011-06-01

The interaction-induced absorption by collisional pairs of H{_2} molecules is an important opacity source in the atmospheres of the outer planets and cool stars. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H{_2}-H{_2}, H{_2}-He, and H{_2}-H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin. Laboratory measurements of interaction-induced absorption spectra by H{_2} pairs exist only at room temperature and below. We show that our results reproduce these measurements closely, so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures. L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, "Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin", International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, "Collision-induced absorption by H{_2} pairs: From hundreds to thousands of Kelvin," J. Phys. Chem. A, published online, DOI: 10.1021/jp109441f L. Frommhold, M. Abel, F. Wang, M. Gustafsson, X. Li, and K. L. C. Hunt, "Infrared atmospheric emission and absorption by simple molecular complexes, from first principles", Mol. Phys. 108, 2265, 2010

The ship-borne infrared searching and tracking system based on the inertial platform

Science.gov (United States)

Li, Yan; Zhang, Haibo

2011-08-01

As a result of the radar system got interferenced or in the state of half silent ,it can cause the guided precision drop badly In the modern electronic warfare, therefore it can lead to the equipment depended on electronic guidance cannot strike the incoming goals exactly. It will need to rely on optoelectronic devices to make up for its shortcomings, but when interference is in the process of radar leading ,especially the electro-optical equipment is influenced by the roll, pitch and yaw rotation ,it can affect the target appear outside of the field of optoelectronic devices for a long time, so the infrared optoelectronic equipment can not exert the superiority, and also it cannot get across weapon-control system "reverse bring" missile against incoming goals. So the conventional ship-borne infrared system unable to track the target of incoming quickly , the ability of optoelectronic rivalry declines heavily.Here we provide a brand new controlling algorithm for the semi-automatic searching and infrared tracking based on inertial navigation platform. Now it is applying well in our XX infrared optoelectronic searching and tracking system. The algorithm is mainly divided into two steps: The artificial mode turns into auto-searching when the deviation of guide exceeds the current scene under the course of leading for radar.When the threshold value of the image picked-up is satisfied by the contrast of the target in the searching scene, the speed computed by using the CA model Least Square Method feeds back to the speed loop. And then combine the infrared information to accomplish the closed-loop control of the infrared optoelectronic system tracking. The algorithm is verified via experiment. Target capturing distance is 22.3 kilometers on the great lead deviation by using the algorithm. But without using the algorithm the capturing distance declines 12 kilometers. The algorithm advances the ability of infrared optoelectronic rivalry and declines the target capturing

Combined effect of solvents and gamma irradiation on the infrared absorption spectra of polyethylene terephthalate

International Nuclear Information System (INIS)

Rabie, S.M.; ElBially, A.; Elshourbaguie, S.

1991-01-01

The combined effect of solvents and gamma irradiation on the intensities of infrared absorption bands of polyethylene terephthalate, particularly the bands sensitive to conformational changes, were studied. The results revealed that solvent treatment of PET results in significant changes in the intensities of its infrared absorption bands and the exposure of PET to gamma radiation in the presence of solvents helps in the appearance of the two bands at 1550 and 1630 cm . Also, the combined effect of solvents and gamma irradiation on the intensities of the absorption bands is greater than the effect of each agent alone. The extent of the induced changes depends on the nature of solvent and the applied dosage. Further more, for any given solvent or dosage, the rate of change of the intensities of the trans band is not equal to that of the gauche bands.3 fig

``New'' energy states lead to phonon-less optoelectronic properties in nanostructured silicon

Science.gov (United States)

Singh, Vivek; Yu, Yixuan; Korgel, Brian; Nagpal, Prashant

2014-03-01

Silicon is arguably one of the most important technological material for electronic applications. However, indirect bandgap of silicon semiconductor has prevented optoelectronic applications due to phonon assistance required for photon light absorption/emission. Here we show, that previously unexplored surface states in nanostructured silicon can couple with quantum-confined energy levels, leading to phonon-less exciton-recombination and photoluminescence. We demonstrate size dependence (2.4 - 8.3 nm) of this coupling observed in small uniform silicon nanocrystallites, or quantum-dots, by direct measurements of their electronic density of states and low temperature measurements. To enhance the optical absorption of the these silicon quantum-dots, we utilize generation of resonant surface plasmon polariton waves, which leads to several fold increase in observed spectrally-resolved photocurrent near the quantum-confined bandedge states. Therefore, these enhanced light emission and absorption enhancement can have important implications for applications of nanostructured silicon for optoelectronic applications in photovoltaics and LEDs.

Pseudo-direct bandgap transitions in silicon nanocrystals: effects on optoelectronics and thermoelectrics

Science.gov (United States)

Singh, Vivek; Yu, Yixuan; Sun, Qi-C.; Korgel, Brian; Nagpal, Prashant

2014-11-01

While silicon nanostructures are extensively used in electronics, the indirect bandgap of silicon poses challenges for optoelectronic applications like photovoltaics and light emitting diodes (LEDs). Here, we show that size-dependent pseudo-direct bandgap transitions in silicon nanocrystals dominate the interactions between (photoexcited) charge carriers and phonons, and hence the optoelectronic properties of silicon nanocrystals. Direct measurements of the electronic density of states (DOS) for different sized silicon nanocrystals reveal that these pseudo-direct transitions, likely arising from the nanocrystal surface, can couple with the quantum-confined silicon states. Moreover, we demonstrate that since these transitions determine the interactions of charge carriers with phonons, they change the light emission, absorption, charge carrier diffusion and phonon drag (Seebeck coefficient) in nanoscaled silicon semiconductors. Therefore, these results can have important implications for the design of optoelectronics and thermoelectric devices based on nanostructured silicon.While silicon nanostructures are extensively used in electronics, the indirect bandgap of silicon poses challenges for optoelectronic applications like photovoltaics and light emitting diodes (LEDs). Here, we show that size-dependent pseudo-direct bandgap transitions in silicon nanocrystals dominate the interactions between (photoexcited) charge carriers and phonons, and hence the optoelectronic properties of silicon nanocrystals. Direct measurements of the electronic density of states (DOS) for different sized silicon nanocrystals reveal that these pseudo-direct transitions, likely arising from the nanocrystal surface, can couple with the quantum-confined silicon states. Moreover, we demonstrate that since these transitions determine the interactions of charge carriers with phonons, they change the light emission, absorption, charge carrier diffusion and phonon drag (Seebeck coefficient) in

Tuning the optoelectronic properties of amorphous MoOx films by reactive sputtering

DEFF Research Database (Denmark)

Fernandes Cauduro, André Luis; Fabrim, Zacarias Eduardo; Ahmadpour, Mehrad

2015-01-01

In this letter, we report on the effect of oxygen partial pressure and sputtering power on amorphous DC-sputtered MoOx films. We observe abrupt changes in the optoelectronic properties of the reported films by increasing the oxygen partial pressure from 1.00 ? 10?3 mbar to 1.37 ? 10?3 mbar during...... significantly the microstructure of the studied films. The presence of states within the band gap due to the lack of oxygen is the most probable mechanism for generat- ing a change in electrical conductivity as well as optical absorption in DC-sputtered MoOx. The large tuning range of the optoelectronic...... properties in these films holds strong promise for their implementation in optoelectronic devices....

Single and Double Infrared Transitions in Rapid Vapor Deposited Parahydrogen Solids: Application to Sample Thickness Determination and Quantitative Infrared Absorption Spectroscopy

National Research Council Canada - National Science Library

Tam, Simon

2001-01-01

...) solid from its infrared (IR) absorption spectrum. Millimeters-thick pH2 solids of exceptional optical clarity can be produced by the rapid vapor deposition method M.E. Fajardo and S. Tam, J. Chem. Phys. 108, 4237 (1998...

Time-resolved infrared absorption study of nine TiO2 photocatalysts

International Nuclear Information System (INIS)

Yamakata, Akira; Ishibashi, Taka-aki; Onishi, Hiroshi

2007-01-01

Electron kinetics of nine TiO 2 catalysts were compared in a microsecond time domain. Each catalyst was band-gap excited with an UV light pulse, and electron-induced absorption of mid infrared light was observed as a function of time delay. The probability of electron-hole recombination in the bulk, electron attachment to adsorbed oxygen, and hole attachment to adsorbed methoxy species was estimated

Highly doped semiconductor plasmonic nanoantenna arrays for polarization selective broadband surface-enhanced infrared absorption spectroscopy of vanillin

Science.gov (United States)

Barho, Franziska B.; Gonzalez-Posada, Fernando; Milla, Maria-Jose; Bomers, Mario; Cerutti, Laurent; Tournié, Eric; Taliercio, Thierry

2017-11-01

Tailored plasmonic nanoantennas are needed for diverse applications, among those sensing. Surface-enhanced infrared absorption (SEIRA) spectroscopy using adapted nanoantenna substrates is an efficient technique for the selective detection of molecules by their vibrational spectra, even in small quantity. Highly doped semiconductors have been proposed as innovative materials for plasmonics, especially for more flexibility concerning the targeted spectral range. Here, we report on rectangular-shaped, highly Si-doped InAsSb nanoantennas sustaining polarization switchable longitudinal and transverse plasmonic resonances in the mid-infrared. For small array periodicities, the highest reflectance intensity is obtained. Large periodicities can be used to combine localized surface plasmon resonances (SPR) with array resonances, as shown in electromagnetic calculations. The nanoantenna arrays can be efficiently used for broadband SEIRA spectroscopy, exploiting the spectral overlap between the large longitudinal or transverse plasmonic resonances and narrow infrared active absorption features of an analyte molecule. We demonstrate an increase of the vibrational line intensity up to a factor of 5.7 of infrared-active absorption features of vanillin in the fingerprint spectral region, yielding enhancement factors of three to four orders of magnitude. Moreover, an optimized readout for SPR sensing is proposed based on slightly overlapping longitudinal and transverse localized SPR.

Highly doped semiconductor plasmonic nanoantenna arrays for polarization selective broadband surface-enhanced infrared absorption spectroscopy of vanillin

Directory of Open Access Journals (Sweden)

Barho Franziska B.

2017-11-01

Full Text Available Tailored plasmonic nanoantennas are needed for diverse applications, among those sensing. Surface-enhanced infrared absorption (SEIRA spectroscopy using adapted nanoantenna substrates is an efficient technique for the selective detection of molecules by their vibrational spectra, even in small quantity. Highly doped semiconductors have been proposed as innovative materials for plasmonics, especially for more flexibility concerning the targeted spectral range. Here, we report on rectangular-shaped, highly Si-doped InAsSb nanoantennas sustaining polarization switchable longitudinal and transverse plasmonic resonances in the mid-infrared. For small array periodicities, the highest reflectance intensity is obtained. Large periodicities can be used to combine localized surface plasmon resonances (SPR with array resonances, as shown in electromagnetic calculations. The nanoantenna arrays can be efficiently used for broadband SEIRA spectroscopy, exploiting the spectral overlap between the large longitudinal or transverse plasmonic resonances and narrow infrared active absorption features of an analyte molecule. We demonstrate an increase of the vibrational line intensity up to a factor of 5.7 of infrared-active absorption features of vanillin in the fingerprint spectral region, yielding enhancement factors of three to four orders of magnitude. Moreover, an optimized readout for SPR sensing is proposed based on slightly overlapping longitudinal and transverse localized SPR.

Infrared absorption characteristics of hydroxyl groups in coal tars

Energy Technology Data Exchange (ETDEWEB)

Cannon, S A; Chu, C J; Hange, R H; Margrave, J L

1987-01-01

Tar evolution was observed over a temperature range of 150-600 C for four coals. Pittsburgh bituminous, Illinois No.6, Rawhide subbituminous, and Texas lignite. Isolation of the evolved tars in a nitrogen matrix at 15 degrees K produced better resolved infrared spectra than those in a coal matrix, thus enhancing structural characterization of the tar molecules. Two distinct hydroxyl functional groups in the tar molecules free of hydrogen bonding were identified for the first time without interference from H/sub 2/O absorptions. These absorptions at 3626.5 cm/sup -1/ have been assigned to phenolic hydroxyls. It is suggested that carboxylic and aliphatic hydroxyl groups do not survive the vaporization process. Tars from Illinois No.6 were found to contain the largest amount of phenolic hydroxyl; Pittsburgh No. 8 tar contains approximately half of that for Illinois No.6 while Rawhide and Texas lignite contain much less phenolic than either of the other coals. 10 references, 6 figures, 1 table.

The Relationship Between Dynamics and Structure in the Far Infrared Absorption Spectrum of Liquid Water

Energy Technology Data Exchange (ETDEWEB)

Woods, K.

2005-01-14

Using an intense source of far-infrared radiation, the absorption spectrum of liquid water is measured at a temperature ranging from 269 to 323 K. In the infrared spectrum we observe modes that are related to the local structure of liquid water. Here we present a FIR measured spectrum that is sensitive to the low frequency (< 100cm{sup -1}) microscopic details that exist in liquid water.

Mid-infrared photonics in silicon and germanium

Science.gov (United States)

Soref, Richard

2010-08-01

Ingenious techniques are needed to extend group IV photonics from near-infrared to mid-infrared wavelengths. If achieved, the reward could be on-chip CMOS optoelectronic systems for use in spectroscopy, chemical and biological sensing, and free-space communications.

Mid-infrared two-photon absorption in an extended-wavelength InGaAs photodetector

Science.gov (United States)

Piccardo, Marco; Rubin, Noah A.; Meadowcroft, Lauren; Chevalier, Paul; Yuan, Henry; Kimchi, Joseph; Capasso, Federico

2018-01-01

We investigate the nonlinear optical response of a commercial extended-wavelength In0.81Ga0.19As uncooled photodetector. Degenerate two-photon absorption in the mid-infrared range is observed using a quantum cascade laser emitting at λ = 4.5 μm as the excitation source. From the measured two-photon photocurrent signal, we extract a two-photon absorption coefficient β(2) = 0.6 ± 0.2 cm/MW, in agreement with the theoretical value obtained from the Eg-3 scaling law. Considering the wide spectral range covered by extended-wavelength InxGa1-xAs alloys, this result holds promise for applications based on two-photon absorption for this family of materials at wavelengths between 1.8 and 5.6 μm.

Study of cancer cell lines with Fourier transform infrared (FTIR)/vibrational absorption (VA) spectroscopy

DEFF Research Database (Denmark)

Uceda Otero, E. P.; Eliel, G. S. N.; Fonseca, E. J. S.

2013-01-01

In this work we have used Fourier transform infrared (FTIR) / vibrational absorption (VA) spectroscopy to study two cancer cell lines: the Henrietta Lacks (HeLa) human cervix carcinoma and 5637 human bladder carcinoma cell lines. Our goal is to experimentally investigate biochemical changes...

Energy levels and far-infrared optical absorption of impurity doped semiconductor nanorings: Intense laser and electric fields effects

Energy Technology Data Exchange (ETDEWEB)

Barseghyan, M.G., E-mail: mbarsegh@ysu.am

2016-11-10

Highlights: • The electron-impurity interaction on energy levels in nanoring have been investigated. • The electron-impurity interaction on far-infrared absorption have been investigated. • The energy levels are more stable for higher values of electric field. - Abstract: The effects of electron-impurity interaction on energy levels and far-infrared absorption in semiconductor nanoring under the action of intense laser and lateral electric fields have been investigated. Numerical calculations are performed using exact diagonalization technique. It is found that the electron-impurity interaction and external fields change the energy spectrum dramatically, and also have significant influence on the absorption spectrum. Strong dependence on laser field intensity and electric field of lowest energy levels, also supported by the Coulomb interaction with impurity, is clearly revealed.

nBn Infrared Detector Containing Graded Absorption Layer

Science.gov (United States)

Gunapala, Sarath D.; Ting, David Z.; Hill, Cory J.; Bandara, Sumith V.

2009-01-01

It has been proposed to modify the basic structure of an nBn infrared photodetector so that a plain electron-donor- type (n-type) semiconductor contact layer would be replaced by a graded n-type III V alloy semiconductor layer (i.e., ternary or quarternary) with appropriate doping gradient. The abbreviation nBn refers to one aspect of the unmodified basic device structure: There is an electron-barrier ("B" ) layer between two n-type ("n" ) layers, as shown in the upper part of the figure. One of the n-type layers is the aforementioned photon-absorption layer; the other n-type layer, denoted the contact layer, collects the photocurrent. The basic unmodified device structure utilizes minority-charge-carrier conduction, such that, for reasons too complex to explain within the space available for this article, the dark current at a given temperature can be orders of magnitude lower (and, consequently, signal-to-noise ratios can be greater) than in infrared detectors of other types. Thus, to obtain a given level of performance, less cooling (and, consequently, less cooling equipment and less cooling power) is needed. [In principle, one could obtain the same advantages by means of a structure that would be called pBp because it would include a barrier layer between two electron-acceptor- type (p-type) layers.] The proposed modifications could make it practical to utilize nBn photodetectors in conjunction with readily available, compact thermoelectric coolers in diverse infrared- imaging applications that could include planetary exploration, industrial quality control, monitoring pollution, firefighting, law enforcement, and medical diagnosis.

Infrared reflection absorption spectroscopy study of radiation-heterogeneous processes in the system of aluminum-hexane

International Nuclear Information System (INIS)

Gadzhieva, N.N.; Rimikhanova, A.N.; Garibov, A.A.

2004-01-01

Full text: Infrared reflection absorption spectroscopy (IRRAS) was applied to study the regularities of radiation conversion of hexane on the surface of aluminum. The research object was the thin polished aluminum plate by mark of AD-00 with reflection coefficient R=0.8†0.85 in infrared range λ=2.2†15 μ . As adsorbate unsaturated vapors of spectroscopy clear hexane were used. The absorption of hexane (C 2 H 14 ) was being studied manometric at pressures P=(0.1†1.0)·10 2 Pa , what corresponded to monolayer value of 1-10. The samples were irradiated with γ-quanta of 60 Co with D=1.03 Gy·s -1 doze rate. Infrared reflection spectrum when linear-polarized radiation fall on the sample under angle ψ=10 o was measured by spectrophotometer 'Specord 71 JR' in diapason of 4000-650cm -1 at the temperature by mean of special reflecting arrangements. Formation of molecular hydrogen (H 2 ) and other gaseous products of decomposition were controlled by chromotographical and infrared spectroscopical methods. The analysis of hexane infrared absorption spectra after radiation-stimulated adsorption on the surface of aluminum, points out the formation of H-bonded hydrocarbon complex ( ν∼2680cm -1 ) with much loosening of C-H bond (the molecular form of absorption) and the possibility of proceeding dissociative absorption with formation of metal-alkyls (ν∼2880, 2920, 2970 cm -1 ). Probability of the last mentioned process, which proceeds in the most defective centers, increases with increasing of γ-radiation doze. It was established that the radiation processes in hetero system Al-ads.C 6 H 14 accelerate the radiolysis of hexane. At all these the radiation decomposition of hexane in hetero system Al-ads.C 6 H 14 is accompanied by formation the surface hydrides (ν∼1700-2000 cm -1 ), acetylene (ν∼3200-3300 cm -1 ), ethylene (ν∼980 cm -1 ), and also gaseous products of molecular hydrogen decomposition (H 2 ) and hydrocarbons C 1 -C 5 (bands with maxima 770, 790

High intersubband absorption in long-wave quantum well infrared photodetector based on waveguide resonance

Science.gov (United States)

Zheng, Yuanliao; Chen, Pingping; Ding, Jiayi; Yang, Heming; Nie, Xiaofei; Zhou, Xiaohao; Chen, Xiaoshuang; Lu, Wei

2018-06-01

A hybrid structure consisting of periodic gold stripes and an overlaying gold film has been proposed as the optical coupler of a long-wave quantum well infrared photodetector. Absorption spectra and field distributions of the structure at back-side normal incidence are calculated by the finite difference time-domain method. The results indicate that the intersubband absorption can be greatly enhanced based on the waveguide resonance as well as the surface plasmon polariton (SPP) mode. With the optimized structural parameters of the periodic gold stripes, the maximal intersubband absorption can exceed 80%, which is much higher than the SPP-enhanced intersubband absorption (the one of the standard device. The relationship between the structural parameters and the waveguide resonant wavelength is derived. Other advantages of the efficient optical coupling based on waveguide resonance are also discussed.

Research and development of photovoltaic power system. Study of carrier dynamics in a-Si from optical and optoelectronic properties; Taiyoko hatsuden system no kenky kaihatsu. Amorphous silicon no koden tokusei to sono carrier dynamics no kogakuteki kenkyu

Energy Technology Data Exchange (ETDEWEB)

Hamakawa, K [Osaka University, Osaka (Japan). Faculty of Engineering Science

1994-12-01

This paper reports the result obtained during fiscal 1994 on research on an optical study of optoelectronic properties of amorphous silicon and its carrier dynamics. Studies have been performed on elucidation of the optoelectronic conversion mechanism in an a-Si film p-i-n junction system and the relationship of the mechanism with the optoelectronic properties. In the studies, optically induced defect level distribution was evaluated by using the modulated optical current spectroscopy, and confirmation was made on model forecast and qualitative agreement, such as large increase in neutral defect levels in association with beam irradiation. In research on elucidation of a film forming mechanism for a-Si based alloys, and material property control, a high-sensitivity reflective infrared spectroscopy was used to observe mechanisms such as treatments and processes given in device fabrication. In research on optical and optoelectronic properties of an s-Si alloy thin film by using the modulated spectroscopy, a new evaluation technology dealing with amorphous semiconductors was developed. The technology separately evaluates carrier migration factors of electrons and holes by combining polarization angle dependence of electro-absorption signals with hole migration measurements. 4 figs.

Time-resolved infrared absorption study of nine TiO{sub 2} photocatalysts

Energy Technology Data Exchange (ETDEWEB)

Yamakata, Akira; Ishibashi, Taka-aki [Kanagawa Academy of Science and Technology (KAST), KSP, Takatsu, Kawasaki 213-0012 (Japan); Onishi, Hiroshi [Kanagawa Academy of Science and Technology (KAST), KSP, Takatsu, Kawasaki 213-0012 (Japan)], E-mail: oni@kobe-u.ac.jp

2007-10-15

Electron kinetics of nine TiO{sub 2} catalysts were compared in a microsecond time domain. Each catalyst was band-gap excited with an UV light pulse, and electron-induced absorption of mid infrared light was observed as a function of time delay. The probability of electron-hole recombination in the bulk, electron attachment to adsorbed oxygen, and hole attachment to adsorbed methoxy species was estimated.

Observation of enhanced infrared absorption in silicon supersaturated with gold by pulsed laser melting of nanometer-thick gold films

Science.gov (United States)

Chow, Philippe K.; Yang, Wenjie; Hudspeth, Quentin; Lim, Shao Qi; Williams, Jim S.; Warrender, Jeffrey M.

2018-04-01

We demonstrate that pulsed laser melting (PLM) of thin 1, 5, and 10 nm-thick vapor-deposited gold layers on silicon enhances its room-temperature sub-band gap infrared absorption, as in the case of ion-implanted and PLM-treated silicon. The former approach offers reduced fabrication complexity and avoids implantation-induced lattice damage compared to ion implantation and pulsed laser melting, while exhibiting comparable optical absorptance. We additionally observed strong broadband absorptance enhancement in PLM samples made using 5- and 10-nm-thick gold layers. Raman spectroscopy and Rutherford backscattering analysis indicate that such an enhancement could be explained by absorption by a metastable, disordered and gold-rich surface layer. The sheet resistance and the diode electrical characteristics further elucidate the role of gold-supersaturation in silicon, revealing the promise for future silicon-based infrared device applications.

Integration of Absorption Feature Information from Visible to Longwave Infrared Spectral Ranges for Mineral Mapping

Directory of Open Access Journals (Sweden)

Veronika Kopačková

2017-09-01

Full Text Available Merging hyperspectral data from optical and thermal ranges allows a wider variety of minerals to be mapped and thus allows lithology to be mapped in a more complex way. In contrast, in most of the studies that have taken advantage of the data from the visible (VIS, near-infrared (NIR, shortwave infrared (SWIR and longwave infrared (LWIR spectral ranges, these different spectral ranges were analysed and interpreted separately. This limits the complexity of the final interpretation. In this study a presentation is made of how multiple absorption features, which are directly linked to the mineral composition and are present throughout the VIS, NIR, SWIR and LWIR ranges, can be automatically derived and, moreover, how these new datasets can be successfully used for mineral/lithology mapping. The biggest advantage of this approach is that it overcomes the issue of prior definition of endmembers, which is a requested routine employed in all widely used spectral mapping techniques. In this study, two different airborne image datasets were analysed, HyMap (VIS/NIR/SWIR image data and Airborne Hyperspectral Scanner (AHS, LWIR image data. Both datasets were acquired over the Sokolov lignite open-cast mines in the Czech Republic. It is further demonstrated that even in this case, when the absorption feature information derived from multispectral LWIR data is integrated with the absorption feature information derived from hyperspectral VIS/NIR/SWIR data, an important improvement in terms of more complex mineral mapping is achieved.

Optoelectronic properties of valence-state-controlled amorphous niobium oxide

Science.gov (United States)

Onozato, Takaki; Katase, Takayoshi; Yamamoto, Akira; Katayama, Shota; Matsushima, Koichi; Itagaki, Naho; Yoshida, Hisao; Ohta, Hiromichi

2016-06-01

In order to understand the optoelectronic properties of amorphous niobium oxide (a-NbO x ), we have investigated the valence states, local structures, electrical resistivity, and optical absorption of a-NbO x thin films with various oxygen contents. It was found that the valence states of Nb ion in a-NbO x films can be controlled from 5+  to 4+  by reducing oxygen pressure during film deposition at room temperature, together with changing the oxide-ion arrangement around Nb ion from Nb2O5-like to NbO2-like local structure. As a result, a four orders of magnitude reduction in the electrical resistivity of a-NbO x films was observed with decreasing oxygen content, due to the carrier generation caused by the appearance and increase of an oxygen-vacancy-related subgap state working as an electron donor. The tunable optoelectronic properties of a-NbO x films by valence-state-control with oxygen-vacancy formation will be useful for potential flexible optoelectronic device applications.

Studies of hydrogen incorporation in hydrogenated amorphous carbon films by infrared absorption spectroscopy

International Nuclear Information System (INIS)

Alameh, R.; Bounouh, Y.; Sadki, A.; Naud, C.; Theye, M.L.

1997-01-01

Author.Hydrogenated amorphous carbon (a-C:H) films presently attract considerable interest because of their potential applications in the domain of multifunctional coatings: transparent in the infrared, very hard, chemically inert, etc...This material is rather complex since it contains C atoms in both sp 3 (diamond) and sp 2 (graphite) electronic configurations, as well as a large concentration of H atoms. Its properties are strongly dependent on the deposition conditions which determine the film microstructure, i.e. the relative proportions of sp 3 and sp 2 C sites, their connection in the network and the hydrogen bonding modes. It has been suggested that the sp 2 C sites tend to cluster into unsaturated chains ans rings, which are then embedded in the sp 3 C sites m atrix . Hydrogen incorporation plays a crucial role in this intrinsic microheterogeneity, which determines the electronic properties, and especially the gap value, of a-C:H. We here present and discuss the results of Fourrier transform infrared absorption spectroscopy measurements performed on a-C:H films prepared under different conditions and submitted to controlled annealing cycles, which exhibit quite different optical gap values (from 1 to 2.5 eV). We carefully analyze the absorption bands detected in the 400-7500 cm -1 spectral range in terms of the vibration modes of C-H and C-C bonds in different local environments and we interpret the results in relation with the film microstructure and optical properties. Special attention is also paid to the absorption background and to the variations of the whole absorption spectra with measurement temperature

Application of mid-infrared tuneable diode laser absorption spectroscopy to plasma diagnostics: a review

International Nuclear Information System (INIS)

Roepcke, J; Lombardi, G; Rousseau, A; Davies, P B

2006-01-01

Within the last decade mid-infrared absorption spectroscopy over a region from 3 to 17μm and based on tuneable lead salt diode lasers, often called tuneable diode laser absorption spectroscopy or TDLAS, has progressed considerably as a powerful diagnostic technique for in situ studies of the fundamental physics and chemistry in molecular plasmas. The increasing interest in processing plasmas containing hydrocarbons, fluorocarbons, organo-silicon and boron compounds has led to further applications of TDLAS because most of these compounds and their decomposition products are infrared active. TDLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species, which is of particular importance for the investigation of reaction kinetic phenomena. Information about gas temperature and population densities can also be derived from TDLAS measurements. A variety of free radicals and molecular ions have been detected by TDLAS. Since plasmas with molecular feed gases are used in many applications such as thin film deposition, semiconductor processing, surface activation and cleaning, and materials and waste treatment, this has stimulated the adaptation of infrared spectroscopic techniques to industrial requirements. The recent development of quantum cascade lasers (QCLs) offers an attractive new option for the monitoring and control of industrial plasma processes. The aim of the present paper is threefold: (i) to review recent achievements in our understanding of molecular phenomena in plasmas (ii) to report on selected studies of the spectroscopic properties and kinetic behaviour of radicals and (iii) to describe the current status of advanced instrumentation for TDLAS in the mid-infrared

New Development of Membrane Base Optoelectronic Devices

Directory of Open Access Journals (Sweden)

Leon Hamui

2017-12-01

Full Text Available It is known that one factor that affects the operation of optoelectronic devices is the effective protection of the semiconductor materials against environmental conditions. The permeation of atmospheric oxygen and water molecules into the device structure induces degradation of the electrodes and the semiconductor. As a result, in this communication we report the fabrication of semiconductor membranes consisting of Magnesium Phthalocyanine-allene (MgPc-allene particles dispersed in Nylon 11 films. These membranes combine polymer properties with organic semiconductors properties and also provide a barrier effect for the atmospheric gas molecules. They were prepared by high vacuum evaporation and followed by thermal relaxation technique. For the characterization of the obtained membranes, Fourier-transform infrared spectroscopy (FT-IR, scanning electron microscopy (SEM, and energy dispersive spectroscopy (EDS were used to determine the chemical and microstructural properties. UV-ViS, null ellipsometry, and visible photoluminescence (PL at room temperature were used to characterize the optoelectronic properties. These results were compared with those obtained for the organic semiconductors: MgPc-allene thin films. Additionally, semiconductor membranes devices have been prepared, and a study of the device electronic transport properties was conducted by measuring electrical current density-voltage (J-V characteristics by four point probes with different wavelengths. The resistance properties against different environmental molecules are enhanced, maintaining their semiconductor functionality that makes them candidates for optoelectronic applications.

Organic optoelectronic materials

CERN Document Server

Li, Yongfang

2015-01-01

This volume reviews the latest trends in organic optoelectronic materials. Each comprehensive chapter allows graduate students and newcomers to the field to grasp the basics, whilst also ensuring that they have the most up-to-date overview of the latest research. Topics include: organic conductors and semiconductors; conducting polymers and conjugated polymer semiconductors, as well as their applications in organic field-effect-transistors; organic light-emitting diodes; and organic photovoltaics and transparent conducting electrodes. The molecular structures, synthesis methods, physicochemical and optoelectronic properties of the organic optoelectronic materials are also introduced and described in detail. The authors also elucidate the structures and working mechanisms of organic optoelectronic devices and outline fundamental scientific problems and future research directions. This volume is invaluable to all those interested in organic optoelectronic materials.

Preparation and near-infrared absorption of nano-SnO{sub 2}/SiO{sub 2} assemblies with doping and without doping

Energy Technology Data Exchange (ETDEWEB)

Hai Shujie [Faculty of Material Science and Chemical Engineering, China University of Geosciences, Lu Mo Road 388, Wuhan 430074 (China); Yan Chunjie, E-mail: chjyan2005@126.co [Engineering Research Center of Nano-Geomaterials, Ministry of Education, China University of Geosciences, Lu Mo Road 388, Wuhan 430074 (China); Yu Hongjie; Xiao Guoqi; Wang Duo [Faculty of Material Science and Chemical Engineering, China University of Geosciences, Lu Mo Road 388, Wuhan 430074 (China)

2009-11-20

The assemblies of nano-SnO{sub 2}/SiO{sub 2} and Sb- or Pd-doped nano-SnO{sub 2}/SiO{sub 2}, in which the nano-SnO{sub 2} particles are located in the pores of mesoporous SiO{sub 2} dry gels, were synthesized. Only for the Sb-doped nano-SnO{sub 2}/SiO{sub 2} assemblies, a broad near-infrared absorption step occurs in the optical absorption spectrum of the wavelength range from 300 to 1500 nm. The near-infrared absorption phenomenon is attributed to electronic transitions from the ground states to the excitation states of the impurity energy levels, which are formed by Sb doping in SnO{sub 2}. With increasing the weight ratio of SnO{sub 2}:SiO{sub 2} or the annealing temperature, the near-infrared absorption step slope side exhibits 'red shift', which is caused by the quantum confinement effect weakening due to the increased SnO{sub 2} crystalline diameter.

Characteristics of the Current-Controlled Phase Transition of VO2 Microwires for Hybrid Optoelectronic Devices

Directory of Open Access Journals (Sweden)

Arash Joushaghani

2015-08-01

Full Text Available The optical and electrical characteristics of the insulator-metal phase transition of vanadium dioxide (VO2 enable the realization of power-efficient, miniaturized hybrid optoelectronic devices. This work studies the current-controlled, two-step insulator-metal phase transition of VO2 in varying microwire geometries. Geometry-dependent scaling trends extracted from current-voltage measurements show that the first step induced by carrier injection is delocalized over the microwire, while the second, thermally-induced step is localized to a filament about 1 to 2 μm wide for 100 nm-thick sputtered VO2 films on SiO2. These effects are confirmed by direct infrared imaging, which also measures the change in optical absorption in the two steps. The difference between the threshold currents of the two steps increases as the microwires are narrowed. Micron- and sub-micron-wide VO2 structures can be used to separate the two phase transition steps in photonic and electronic devices.

Measuring processes with opto-electronic semiconductor components

International Nuclear Information System (INIS)

1985-01-01

This is a report on the state of commercially available semiconductor emitters and detectors for the visible, near, middle and remote infrared range. A survey is given on the distance, speed, flow and length measuring techniques using opto-electronic components. Automatic focussing, the use of light barriers, non-contact temperature measurements, spectroscopic gas, liquid and environmental measurement techniques and gas analysis in medical techniques show further applications of the new components. The modern concept of guided radiation in optical fibres and their use in system technology is briefly explained. (DG) [de

A full-duplex working integrated optoelectronic device for optical interconnect

Science.gov (United States)

Liu, Kai; Fan, Huize; Huang, Yongqing; Duan, Xiaofeng; Wang, Qi; Ren, Xiaomin; Wei, Qi; Cai, Shiwei

2018-05-01

In this paper, a full-duplex working integrated optoelectronic device is proposed. It is constructed by integrating a vertical cavity surface emitting laser (VCSEL) unit above a resonant cavity enhanced photodetector (RCE-PD) unit. Analysis shows that, the VCSEL unit has a threshold current of 1 mA and a slop efficiency of 0.66 W/A at 849.7 nm, the RCE-PD unit obtains its maximal absorption quantum efficiency of 90.24% at 811 nm with a FWHM of 4 nm. Moreover, the two units of the proposed integrated device can work independently from each other. So that the proposed integrated optoelectronic device can work full-duplex. It can be applied for single fiber bidirectional optical interconnects system.

Near-infrared radiation absorption properties of covellite (CuS using first-principles calculations

Directory of Open Access Journals (Sweden)

Lihua Xiao

2016-08-01

Full Text Available First-principles density functional theory was used to investigate the electronic structure, optical properties and the origin of the near-infrared (NIR absorption of covellite (CuS. The calculated lattice constant and optical properties are found to be in reasonable agreement with experimental and theoretical findings. The electronic structure reveals that the valence and conduction bands of covellite are determined by the Cu 3d and S 3p states. By analyzing its optical properties, we can fully understand the potential of covellite (CuS as a NIR absorbing material. Our results show that covellite (CuS exhibits NIR absorption due to its metal-like plasma oscillation in the NIR range.

Unraveling the Role of Π - Conjugation in Thiophene Oligomers for Optoelectronic Properties by DFT/TDDFT Approach

Directory of Open Access Journals (Sweden)

Gajalakshmi

Full Text Available ABSTRACT Thiophene oligomer has been investigated using DFT/TDDFT calculations with an aim to check its suitability for opto electronic applications and also to analyse the influence of π-bridge. Our results revealed that thiophene oligomers have excellent π-conjugation throughout. FMO analysis give an estimate of band gap of thiophene oligomer and further revealed HOMO are localized on π - bridge, donor group and LUMO are localized on π - bridge and acceptor group. A TDDFT calculation has been performed to understand the absorption properties of them in gas phase and solvent phase. PCM calculations convey that absorption maxima show positive solvatochromism. Among the designed candidates, the one with more π - bridge show higher wavelength of absorption maxima and would be a choice for better optoelectronic materials. NBO analysis provides support for complete delocalization in these systems. It is interesting to note that oligomer with more π-bridge display an enhanced optoelectronic properties than with less π - bridge.

Beyond Donor-Acceptor (D-A) Approach: Structure-Optoelectronic Properties-Organic Photovoltaic Performance Correlation in New D-A1 -D-A2 Low-Bandgap Conjugated Polymers.

Science.gov (United States)

Chochos, Christos L; Drakopoulou, Sofia; Katsouras, Athanasios; Squeo, Benedetta M; Sprau, Christian; Colsmann, Alexander; Gregoriou, Vasilis G; Cando, Alex-Palma; Allard, Sybille; Scherf, Ullrich; Gasparini, Nicola; Kazerouni, Negar; Ameri, Tayebeh; Brabec, Christoph J; Avgeropoulos, Apostolos

2017-04-01

Low-bandgap near-infrared polymers are usually synthesized using the common donor-acceptor (D-A) approach. However, recently polymer chemists are introducing more complex chemical concepts for better fine tuning of their optoelectronic properties. Usually these studies are limited to one or two polymer examples in each case study so far, though. In this study, the dependence of optoelectronic and macroscopic (device performance) properties in a series of six new D-A 1 -D-A 2 low bandgap semiconducting polymers is reported for the first time. Correlation between the chemical structure of single-component polymer films and their optoelectronic properties has been achieved in terms of absorption maxima, optical bandgap, ionization potential, and electron affinity. Preliminary organic photovoltaic results based on blends of the D-A 1 -D-A 2 polymers as the electron donor mixed with the fullerene derivative [6,6]-phenyl-C 71 -butyric acid methyl ester demonstrate power conversion efficiencies close to 4% with short-circuit current densities (J sc ) of around 11 mA cm -2 , high fill factors up to 0.70, and high open-circuit voltages (V oc s) of 0.70 V. All the devices are fabricated in an inverted architecture with the photoactive layer processed in air with doctor blade technique, showing the compatibility with roll-to-roll large-scale manufacturing processes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of Molecular Conformations and Microstructure on the Optoelectronic Properties of Conjugated Polymers

KAUST Repository

Botiz, Ioan; Stingelin, Natalie

2014-01-01

It is increasingly obvious that the molecular conformations and the long-range arrangement that conjugated polymers can adopt under various experimental conditions in bulk, solutions or thin films, significantly impact their resulting optoelectronic properties. As a consequence, the functionalities and efficiencies of resulting organic devices, such as field-effect transistors, light-emitting diodes, or photovoltaic cells, also dramatically change due to the close structure/property relationship. A range of structure/optoelectronic properties relationships have been investigated over the last few years using various experimental and theoretical methods, and, further, interesting correlations are continuously revealed by the scientific community. In this review, we discuss the latest findings related to the structure/optoelectronic properties interrelationships that exist in organic devices fabricated with conjugated polymers in terms of charge mobility, absorption, photoluminescence, as well as photovoltaic properties. © 2014 by the authors.

Influence of Molecular Conformations and Microstructure on the Optoelectronic Properties of Conjugated Polymers

Directory of Open Access Journals (Sweden)

Ioan Botiz

2014-03-01

Full Text Available It is increasingly obvious that the molecular conformations and the long-range arrangement that conjugated polymers can adopt under various experimental conditions in bulk, solutions or thin films, significantly impact their resulting optoelectronic properties. As a consequence, the functionalities and efficiencies of resulting organic devices, such as field-effect transistors, light-emitting diodes, or photovoltaic cells, also dramatically change due to the close structure/property relationship. A range of structure/optoelectronic properties relationships have been investigated over the last few years using various experimental and theoretical methods, and, further, interesting correlations are continuously revealed by the scientific community. In this review, we discuss the latest findings related to the structure/optoelectronic properties interrelationships that exist in organic devices fabricated with conjugated polymers in terms of charge mobility, absorption, photoluminescence, as well as photovoltaic properties.

Influence of Molecular Conformations and Microstructure on the Optoelectronic Properties of Conjugated Polymers

KAUST Repository

Botiz, Ioan

2014-03-19

It is increasingly obvious that the molecular conformations and the long-range arrangement that conjugated polymers can adopt under various experimental conditions in bulk, solutions or thin films, significantly impact their resulting optoelectronic properties. As a consequence, the functionalities and efficiencies of resulting organic devices, such as field-effect transistors, light-emitting diodes, or photovoltaic cells, also dramatically change due to the close structure/property relationship. A range of structure/optoelectronic properties relationships have been investigated over the last few years using various experimental and theoretical methods, and, further, interesting correlations are continuously revealed by the scientific community. In this review, we discuss the latest findings related to the structure/optoelectronic properties interrelationships that exist in organic devices fabricated with conjugated polymers in terms of charge mobility, absorption, photoluminescence, as well as photovoltaic properties. © 2014 by the authors.

Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin

Directory of Open Access Journals (Sweden)

Xiaoping Li

2010-01-01

Full Text Available Collision-induced absorption by hydrogen and helium in the stellar atmospheres of cool white dwarfs causes the emission spectra to differ significantly from the expected blackbody spectra of the cores. For detailed modeling of radiative processes at temperatures up to 7000 K, the existing H2–H2 induced dipole and potential energy surfaces of high quality must be supplemented by calculations with the H2 bonds stretched or compressed far from the equilibrium length. In this work, we describe new dipole and energy surfaces, based on more than 20 000 ab initio calculations for H2–H2. Our results agree well with previous ab initio work (where those data exist; the calculated rototranslational absorption spectrum at 297.5 K matches experiment similarly well. We further report the calculated absorption spectra of H2–H2 for frequencies from the far infrared to 20 000 cm−1, at temperatures of 600 K, 1000 K, and 2000 K, for which there are no experimental data.

Infrared Absorption Spectroscopy and Chemical Kinetics of Free Radicals

Energy Technology Data Exchange (ETDEWEB)

Curl, Robert F; Glass, Graham

2004-11-01

This research was directed at the detection, monitoring, and study of the chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. Work on the reaction of OH with acetaldehyde has been completed and published and work on the reaction of O({sup 1}D) with CH{sub 4} has been completed and submitted for publication. In the course of our investigation of branching ratios of the reactions of O({sup 1}D) with acetaldehyde and methane, we discovered that hot atom chemistry effects are not negligible at the gas pressures (13 Torr) initially used. Branching ratios of the reaction of O({sup 1}D) with CH{sub 4} have been measured at a tenfold higher He flow and fivefold higher pressure.

Approaching total absorption at near infrared in a large area monolayer graphene by critical coupling

Energy Technology Data Exchange (ETDEWEB)

Liu, Yonghao; Chadha, Arvinder; Zhao, Deyin; Shuai, Yichen; Menon, Laxmy; Yang, Hongjun; Zhou, Weidong, E-mail: wzhou@uta.edu [Nanophotonics Lab, Department of Electrical Engineering, University of Texas at Arlington, Arlington, Texas 76019 (United States); Piper, Jessica R.; Fan, Shanhui [Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Jia, Yichen; Xia, Fengnian [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520 (United States); Ma, Zhenqiang [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2014-11-03

We demonstrate experimentally close to total absorption in monolayer graphene based on critical coupling with guided resonances in transfer printed photonic crystal Fano resonance filters at near infrared. Measured peak absorptions of 35% and 85% were obtained from cavity coupled monolayer graphene for the structures without and with back reflectors, respectively. These measured values agree very well with the theoretical values predicted with the coupled mode theory based critical coupling design. Such strong light-matter interactions can lead to extremely compact and high performance photonic devices based on large area monolayer graphene and other two–dimensional materials.

Preparation and infrared absorption properties of buried SiC layers

International Nuclear Information System (INIS)

Yan Hui; Chen Guanghua; Wong, S.P.; Kwok, R.W.M.

1997-01-01

Buried SiC layers were formed by using a metal vapor vacuum arc (MEVVA) ion source, with C + ions implanted into Si substrates under different doses. In the present study, the extracted voltage was 50 kV and the ion dose was varied from 3.0 x 10 17 to 1.6 x 10 18 cm -2 . According to infrared absorption measurements, it was fount that the structure of the buried SiC layers depended on the ion dose. Moreover, the results also demonstrated that the buried SiC layers including cubic crystalline SiC could be synthesized at an averaged substrate temperature of lower than 400 degree C with the MEVVA ion source

Nitrogen and hydrogen related infrared absorption in CVD diamond films

Energy Technology Data Exchange (ETDEWEB)

Titus, E. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal)]. E-mail: elby@mec.ua.pt; Ali, N. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Cabral, G. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Madaleno, J.C. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Neto, V.F. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Gracio, J. [Department of Mechanical Engineering, University of Aveiro, 3810-193 (Portugal); Ramesh Babu, P [Materials Ireland, Polymer research Centre, School of Physics, Dublin (Ireland); Sikder, A.K. [Department of Physics, Indian Institute of Technology (IIT), Bombay (India); Okpalugo, T.I. [Northern Ireland Bio-Engineering Centre, NIBEC, University of Ulster (United Kingdom); Misra, D.S. [Department of Physics, Indian Institute of Technology (IIT), Bombay (India)

2006-09-25

In this paper, we investigate on the presence of hydrogen and nitrogen related infrared absorptions in chemical vapour deposited (CVD) diamond films. Investigations were carried out in cross sections of diamond windows, deposited using hot filament CVD (HFCVD). The results of Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) and Raman spectroscopy carried out in a cross section of self-standing diamond sheets are presented. The FTIR spectra showed several features that have not been reported before. In order to confirm the frequency of nitrogen related vibrations, ab-initio calculations were carried out using GAMESS program. The investigations showed the presence of several C-N related peaks in one-phonon (1000-1333 cm{sup -1}). The deconvolution of the spectra in the three-phonon region (2700-3150 cm{sup -1}) also showed a number of vibration modes corresponding to sp {sup m}CH {sub n} phase of carbon. Elastic recoil detection analysis (ERDA) was employed to compare the H content measured using FTIR technique. Using these measurements we point out that the oscillator strength of the different IR modes varies depending upon the structure and H content of CVD diamond sheets.

Transferable, conductive TiO{sub 2} nanotube membranes for optoelectronics

Energy Technology Data Exchange (ETDEWEB)

Liu, Guohua [School of Energy and Environment, Anhui University of Technology, Maanshan 243002 (China); Department of Micro and Nano Systems Technology, Vestfold University College, Horten 3184 (Norway); Chen, Ting [School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Sun, Yunlan; Chen, Guang [School of Energy and Environment, Anhui University of Technology, Maanshan 243002 (China); Wang, Kaiying, E-mail: Kaiying.Wang@hbv.no [Department of Micro and Nano Systems Technology, Vestfold University College, Horten 3184 (Norway)

2014-08-30

Graphical abstract: An optoelectronic device with vertical architecture offers straight conducting filaments for electron transportation. - Highlights: • Highly porous TiO{sub 2} nanotube membranes are prepared by two-step anodization. • An optoelectronic device is integrated with photocurrent transportation along the nanotube axial. • Straight conducting nano-filaments are beneficial for electron transportation. • Photoconductive performances are demonstrated under front/back-illumination. - Abstract: We report a facile approach for preparing free-standing and crystalline TiO{sub 2} nanotube membranes (TNMs) by taking advantage of differential mechanical stress between two anodic layers. The membrane exhibits visible light transmittance (∼40%) and UV absorption (∼99%) with good flexibility, which is favorable to integrate with substrates in optoelectronics. A sandwich-type device is assembled through stacking the membrane and substrates. The dependence of current-perpendicular-to-membrane vs applied voltage shows a remarkable photoconductive performance for both front and back illumination. The photocurrent value increases ∼2 or 3 orders magnitude under UV light radiation as compared to that in darkness. The photoresponse is arisen from high internal gain caused by hole trapping along the nanotube walls. This work is crucial for understanding intrinsic optical properties of nanostructured membranes.

Simultaneous measurement of thermal diffusivity and effective infrared absorption coefficient in IR semitransparent and semiconducting n-CdMgSe crystals using photothermal radiometry

Energy Technology Data Exchange (ETDEWEB)

Pawlak, M., E-mail: mpawlak@fizyka.umk.pl [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziądzka 5/7, Toruń (Poland); Maliński, M. [Department of Electronics and Computer Science, Koszalin University of Technology, 2 Śniadeckich St., Koszalin 75-453 (Poland)

2015-01-10

Highlights: • The new method of determination of the effective infrared absorption coefficient is presented. • The method can be used for transparent samples for the excitation radiation. • The effect of aluminum foil on the PTR signal in a transmission configuration is discussed. - Abstract: In this paper we propose a new procedure of simultaneous estimation of the effective infrared optical absorption coefficient and the thermal diffusivity of solid state samples using the photothermal infrared radiometry method in the transmission configuration. The proposed procedure relies on the analysis of the frequency dependent signal obtained from the samples covered with thin aluminum foil. This method can be applied for both optically opaque and transparent samples. The proposed method is illustrated with the results of the thermal diffusivity and the effective IR absorption coefficient obtained for several Cd{sub 1−x}Mg{sub x}Se crystals.

Ultrafast Mid-Infrared Intra-Excitonic Response of Individualized Single-Walled Carbon Nanotubes

International Nuclear Information System (INIS)

Wang, Jigang; Graham, Matt W.; Ma, Yingzhong; Fleming, Graham R.; Kaindl, Robert A.

2009-01-01

The quasi-1D confinement and reduced screening of photoexcited charges in single-walled carbon nanotubes (SWNTs) entails strongly-enhanced Coulomb interactions and exciton binding energies. Such amplified electron-hole (e-h) correlations have important implications for both fundamental physics and optoelectronic applications of nanotubes. The availability of 'individualized' SWNT ensembles with bright and structured luminescence has rendered specific tube chiralities experimentally accessible. In these samples, evidence for excitonic behavior was found in absorption-luminescence maps, two-photon excited luminescence, or ultrafast carrier dynamics. Here, we report ultrafast mid-infrared (mid-IR) studies of individualized SWNTs, evidencing strong photoinduced absorption around 200 meV in semiconducting tubes of (6,5) and (7,5) chiralities. This manifests the observation of quasi-1D intra-excitonic transitions between different relative-momentum states, in agreement with the binding energy and calculated oscillator strength. Our measurements further reveal a saturation of the photoinduced absorption with increasing phase-space filling of the correlated e-h pairs. The transient mid-IR response represents a new tool, unhindered by restrictions of momentum or interband dipole moment, to investigate the density and dynamics of SWNT excitons.

Infrared absorption spectra of selenate compounds of indium (3)

International Nuclear Information System (INIS)

Kharitonov, Yu.Ya.; Kadoshnikova, N.V.; Tananaev, I.V.

1979-01-01

Obtained and discussed are infrared absorption spectra (400-4000 cm -1 ) of the following indium selenates: In 2 (SeO 4 ) 3 x5H 2 O, In 2 (SeO 4 ) 3 x9H 2 O, NaIn(SeO 4 ) 2 x6H 2 O, NaIn(SeO 4 ) 2 xH 2 O, MIn(SeO 4 ) 2 x4H 2 O (M=NH 4 , K, Rb), CsIn(SeO 4 ) 2 x2H 2 O, Na 3 In(SeO 4 ) 3 x7H 2 O, MIn(SeO 4 ) 2 (M=NH 4 , Na, K, Rb, Cs), M 2 InOH(SeO 4 ) 2 xyH 2 O (M=NH 4 , Na, K, Rb) and K 2 InOD(SeO 4 ) 2 xyD 2 O

Source brightness fluctuation correction of solar absorption fourier transform mid infrared spectra

Directory of Open Access Journals (Sweden)

T. Ridder

2011-06-01

Full Text Available The precision and accuracy of trace gas observations using solar absorption Fourier Transform infrared spectrometry depend on the stability of the light source. Fluctuations in the source brightness, however, cannot always be avoided. Current correction schemes, which calculate a corrected interferogram as the ratio of the raw DC interferogram and a smoothed DC interferogram, are applicable only to near infrared measurements. Spectra in the mid infrared spectral region below 2000 cm⁻¹ are generally considered uncorrectable, if they are measured with a MCT detector. Such measurements introduce an unknown offset to MCT interferograms, which prevents the established source brightness fluctuation correction. This problem can be overcome by a determination of the offset using the modulation efficiency of the instrument. With known modulation efficiency the offset can be calculated, and the source brightness correction can be performed on the basis of offset-corrected interferograms. We present a source brightness fluctuation correction method which performs the smoothing of the raw DC interferogram in the interferogram domain by an application of a running mean instead of high-pass filtering the corresponding spectrum after Fourier transformation of the raw DC interferogram. This smoothing can be performed with the onboard software of commercial instruments. The improvement of MCT spectra and subsequent ozone profile and total column retrievals is demonstrated. Application to InSb interferograms in the near infrared spectral region proves the equivalence with the established correction scheme.

Near-infrared diode laser absorption diagnostic for temperature and water vapor in a scramjet combustor

International Nuclear Information System (INIS)

Liu, Jonathan T.C.; Rieker, Gregory B.; Jeffries, Jay B.; Gruber, Mark R.; Carter, Campbell D.; Mathur, Tarun; Hanson, Ronald K.

2005-01-01

Tunable diode laser absorption measurements of gas temperature and water concentration were made at the exit of a model scramjet combustor fueled on JP-7. Multiplexed, fiber-coupled, near-infrared distributed feedback lasers were used to probe three water vapor absorption features in the 1.34-1.47 μm spectral region (2v1and v1+ v3overtone bands). Ratio thermometry was performed using direct-absorption wavelength scans of isolated features at a 4-kHz repetition rate, as well as 2f wavelength modulation scans at a 2-kHz scan rate. Large signal-to-noise ratios demonstrate the ability of the optimally engineered optical hardware to reject beam steering and vibration noise. Successful measurements were made at full combustion conditions for a variety of fuel/air equivalence ratios and at eight vertical positions in the duct to investigate spatial uniformity. The use of three water vapor absorption features allowed for preliminary estimates of temperature distributions along the line of sight. The improved signal quality afforded by 2f measurements, in the case of weak absorption, demonstrates the utility of a scanned wavelength modulation strategy in such situations

Optical absorption analysis of quaternary molybdate- and tungstate-ordered double perovskites

Energy Technology Data Exchange (ETDEWEB)

Tablero, C., E-mail: ctablero@etsit.upm.es

2015-08-05

Highlights: • These compounds present a high optical absorption. • The absorption coefficients using different DFT + U alternatives have been compared. • The absorption coefficients have been split into different contributions. • The maximum efficiency is near the maximum efficiency for multiple-gap solar cells. - Abstract: Quaternary-ordered double perovskite A{sub 2}MM′O{sub 6} (M = Mo,W) semiconductors are a group of materials with a variety of photocatalytic and optoelectronic applications. An analysis focused on the optoelectronic properties is carried out using first-principles density-functional theory with several U orbital-dependent one-electron potentials applied to different orbital subspaces. The structural non-equivalence of the atoms resulting from the symmetry has been taken in account. In order to analyze optical absorption in these materials deeply, the absorption coefficients have been split into inter- and intra-non-equivalent species contributions. The results indicate that the effect of the A and M′ atoms on the optical properties are minimal whereas the largest contribution comes from the non-equivalent O atoms to M transitions.

Airborne Laser Infrared Absorption Spectrometer (ALIAS-II) for in situ Atmospheric Measurements of N(sub 2)0, CH(sub 4), CO, HCl, and NO(sub 2) from Balloon or RPA Platforms

Science.gov (United States)

Scott, D.; Herman, R.; Webster, C.; May, R.; Flesch, G.; Moyer, E.

1998-01-01

The Airborne Laser Infrared Absorption Spectrometer II (ALIAS-II) is a lightweight, high-resolution (0.0003 cm-1), scanning, mid-infrared absorption spectrometer based on cooled (80 K) lead-salt tunable diode laser sources.

Direct Determination of the Absorption of Graphene Mono- and Multi-layers in the Visible and Near-Infrared

Science.gov (United States)

Wu, Yang; Mak, Kin Fai; Lui, Chun Hung; Maultzsch, Janina; Heinz, Tony

2008-03-01

Single-crystal mono- and multi-layer graphene samples were prepared by mechanical exfoliation on quartz substrates. The absorption spectra of samples of 1 -- 8 monolayer thickness were measured in the optical and near-infrared range. The absorption coefficient was found to be largely independent of photon energy and linear in the number of graphene layers. Such absorption measurements can thus be used to determine the thickness of mesoscopic graphite to monolayer accuracy, as already demonstrated in the context of Rayleigh scattering [Casiraghi et al. Nano Letters 2007]. By analysis of the optical transmission problem for a thin film at the air-quartz interface, we deduced an absorption of 2.3% per layer. The magnitude of the monolayer absorption agrees with the value of πα, where α is the fine-structure constant, and corresponds the result obtained from a tight-binding model of the graphene electronic structure [Gusynin et al. PRL 2006]. The predicted (and measured) optical absorption, we note, is equivalent to a constant optical conductance ofπe^22h=6.09x10-5φ-1.

Broadband enhancement of infrared absorption in microbolometers using Ag nanocrystals

International Nuclear Information System (INIS)

Hyun, Jerome K.; Ahn, Chi Won; Kim, Woo Choong; Kim, Tae Hyun; Hyun, Moon Seop; Kim, Hee Yeoun; Park, Jae Hong; Lee, Won-Oh

2015-01-01

High performance microbolometers are widely sought for thermal imaging applications. In order to increase the performance limits of microbolometers, the responsivity of the device to broadband infrared (IR) radiation needs to be improved. In this work, we report a simple, quick, and cost-effective approach to modestly enhance the broadband IR response of the device by evaporating Ag nanocrystals onto the light entrance surface of the device. When irradiated with IR light, strong fields are built up within the gaps between adjacent Ag nanocrystals. These fields resistively generate heat in the nanocrystals and underlying substrate, which is transduced into an electrical signal via a resistive sensing element in the device. Through this method, we are able to enhance the IR absorption over a broadband spectrum and improve the responsivity of the device by ∼11%

Effect of methyl substitution on optoelectronic properties of 1,3,6,8-tetraphenyl pyrenes

Directory of Open Access Journals (Sweden)

LIU Yanling

2014-06-01

Full Text Available Geometric structures of the ground states and excited states,frontier molecular orbitals,ionization potentials,electron affinities,reorganization energies,and absorption and emission spectra of three novel methyl-substituted 1,3,6,8-tetra-phenylpyrenes were studied theoretically by quantum-chemical methods,such as density functional theory (DFT.The results show that the position of methyl substituent on benzene ring has much effect on the optoelectronic properties of methyl-substituted 1,3,6,8-tetra-phenylpyrenes.Interestingly,the geometric structures and optoelectronic properties of the designed compound 1,3,6,8-tetra-p-tolylpyrene (TPPy are similar to those of 1,3,6,8-tetrakis(3,5-dimethylphenylpyrene (TDMPPy,which is worthy of being further researched.

Indirect absorption spectroscopy using quantum cascade lasers: mid-infrared refractometry and photothermal spectroscopy.

Science.gov (United States)

Pfeifer, Marcel; Ruf, Alexander; Fischer, Peer

2013-11-04

We record vibrational spectra with two indirect schemes that depend on the real part of the index of refraction: mid-infrared refractometry and photothermal spectroscopy. In the former, a quantum cascade laser (QCL) spot is imaged to determine the angles of total internal reflection, which yields the absorption line via a beam profile analysis. In the photothermal measurements, a tunable QCL excites vibrational resonances of a molecular monolayer, which heats the surrounding medium and changes its refractive index. This is observed with a probe laser in the visible. Sub-monolayer sensitivities are demonstrated.

Wide-area remote-sensing system of pollution and gas dispersal by near-infrared absorption based on low-loss optical fiber network

Science.gov (United States)

Inaba, H.

1986-01-01

An all optical remote sensing system utilizing long distance, ultralow loss optical fiber networks is studied and discussed for near infrared absorption measurements of combustible and/or explosive gases such as CH4 and C3H8 in our environment, including experimental results achieved in a diameter more than 20 km. The use of a near infrared wavelength range is emphasized.

Modelling of infrared multiphoton absorption and dissociation for design of reactors for isotope separation by lasers

International Nuclear Information System (INIS)

Takeuchi, Kazuo; Nakane, Ryohei; Inoue, Cihiro

1981-01-01

A series of experiments were performed on infrared laser beam absorption (multiphoton absorption) and subsequent dissociation (multiphoton dissociation) of CF 3 Cl to propose models for the design of reactors for isotope separation by lasers. A parallel beam geometry was utilized in batch irradiation experiments to make direct compilation of lumped-parameter data possible. Multiphoton absorption is found to be expressed by a power-law extension of the law of Lambert and by an addition of a new term for buffer gas effect to the law of Beer. For reaction analysis, a method to evaluate the effect of incomplete mixing on apparent reaction rates is first presented. Secondly, multiphoton dissociation of Cf 3 Cl is found to occur in pseudo-first order fashion and the specific reaction rates for different beam fluence are shown to be correlated to the absorbed energy. (author)

Telemedicine optoelectronic biomedical data processing system

Science.gov (United States)

Prosolovska, Vita V.

2010-08-01

The telemedicine optoelectronic biomedical data processing system is created to share medical information for the control of health rights and timely and rapid response to crisis. The system includes the main blocks: bioprocessor, analog-digital converter biomedical images, optoelectronic module for image processing, optoelectronic module for parallel recording and storage of biomedical imaging and matrix screen display of biomedical images. Rated temporal characteristics of the blocks defined by a particular triggering optoelectronic couple in analog-digital converters and time imaging for matrix screen. The element base for hardware implementation of the developed matrix screen is integrated optoelectronic couples produced by selective epitaxy.

Two-crystal mid-infrared optical parametric oscillator for absorption and dispersion dual-comb spectroscopy.

Science.gov (United States)

Jin, Yuwei; Cristescu, Simona M; Harren, Frans J M; Mandon, Julien

2014-06-01

We present a femtosecond optical parametric oscillator (OPO) containing two magnesium-doped periodically poled lithium niobate crystals in a singly resonant ring cavity, pumped by two mode-locked Yb-fiber lasers. As such, the OPO generates two idler combs (up to 220 mW), covering a wavelength range from 2.7 to 4.2 μm, from which a mid-infrared dual-comb Fourier transform spectrometer is constructed. By detecting the heterodyning signal between the two idler beams a full broadband spectrum of a molecular gas can be observed over 250  cm(-1) within 70 μs with a spectral resolution of 15 GHz. The absorption and dispersion spectra of acetylene and methane have been measured around 3000  cm(-1), indicating that this OPO represents an ideal broadband mid-infrared source for fast chemical sensing.

Gold/Chitosan Nanocomposites with Specific Near Infrared Absorption for Photothermal Therapy Applications

Directory of Open Access Journals (Sweden)

Guandong Zhang

2012-01-01

Full Text Available Gold/chitosan nanocomposites were synthesized and evaluated as a therapeutic agent for the photothermal therapy. Gold nanoparticles (Au NPs with controllable optical absorption in the near infrared (NIR region were prepared by the reaction of chloroauric acid and sodium thiosulfate. To apply these particles to cancer therapy, the bare Au NPs were coated with chitosan (CS, O-carboxymethyl chitosan (CMCS, and a blend of CS and CMCS for utilizations in physiologic conditions. The surface properties, optical stability, and photothermal ablation efficiency on hepatocellular carcinoma cells (HepG2 and human dermal fibroblast cells (HDF demonstrate that these gold nanocomposites have great potential as a therapeutic agent in in vitro tests. The CS-coated nanocomposites show the highest efficiency for the photo-ablation on the HepG2 cells, and the CS and CMCS blended coated particles show the best discrimination between the cancer cell and normal cells. The well-controlled NIR absorption and the biocompatible surface of these nanocomposites allow low-power NIR laser activation and low-dosage particle injection for the cancer cell treatment.

Modeling of light absorption in tissue during infrared neural stimulation

Science.gov (United States)

Thompson, Alexander C.; Wade, Scott A.; Brown, William G. A.; Stoddart, Paul R.

2012-07-01

A Monte Carlo model has been developed to simulate light transport and absorption in neural tissue during infrared neural stimulation (INS). A range of fiber core sizes and numerical apertures are compared illustrating the advantages of using simulations when designing a light delivery system. A range of wavelengths, commonly used for INS, are also compared for stimulation of nerves in the cochlea, in terms of both the energy absorbed and the change in temperature due to a laser pulse. Modeling suggests that a fiber with core diameter of 200 μm and NA=0.22 is optimal for optical stimulation in the geometry used and that temperature rises in the spiral ganglion neurons are as low as 0.1°C. The results show a need for more careful experimentation to allow different proposed mechanisms of INS to be distinguished.

Infrared absorption of gaseous ClCS detected with time-resolved Fourier-transform spectroscopy

International Nuclear Information System (INIS)

Chu, Li-Kang; Han, Hui-Ling; Lee, Yuan-Pern

2007-01-01

A transient infrared absorption spectrum of gaseous ClCS was detected with a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. ClCS was produced upon irradiating a flowing mixture of Cl 2 CS and N 2 or CO 2 with a KrF excimer laser at 248 nm. A transient band in the region of 1160-1220 cm -1 , which diminished on prolonged reaction, is assigned to the C-S stretching (ν 1 ) mode of ClCS. Calculations with density-functional theory (B3P86 and B3LYP/aug-cc-pVTZ) predict the geometry, vibrational wave numbers, and rotational parameters of ClCS. The rotational contour of the spectrum of ClCS simulated based on predicted rotational parameters agrees satisfactorily with experimental observation; from spectral simulation, the band origin is determined to be at 1194.4 cm -1 . Reaction kinetics involving ClCS, CS, and CS 2 are discussed

Quantification of atmospheric formaldehyde by infrared absorption spectroscopy

Science.gov (United States)

Hoffnagle, John; Fleck, Derek; Rella, Chris; Kim-Hak, David

2017-04-01

Formaldehyde is a toxic, carcinogenic compound that can contaminate ambient air as a result of combustion or outgassing of commercial products such as adhesives used to fabricate plywood and to affix indoor carpeting. Like many small molecules, formaldehyde has an infrared absorption spectrum exhibiting bands of ro-vibrational transitions that are well resolved at low pressure and therefore well suited for optical analysis of formaldehyde concentration. We describe progress in applying cavity ring-down spectroscopy of the 2v5 band (the first overtone of the asymmetric C-H stretch, origin at 1770 nm) to the quantitative analysis of formaldehyde concentration in ambient air. Preliminary results suggest that a sensitivity of 1-2 ppb in a measurement interval of a few seconds, and 0.1-0.2 ppb in a few minutes, should be achievable with a compact, robust, and field-deployable instrument. Finally, we note that recent satellites monitoring snapshots of formaldehyde columns give insights into global formaldehyde production, migration and lifetime. The ability to monitor formaldehyde with a small and portable analyzer has the potential to aid in validation of these snapshots and to provide complementary data to show vertical dispersions with high spatial accuracy.

High-responsivity graphene/InAs nanowire heterojunction near-infrared photodetectors with distinct photocurrent on/off ratios.

Science.gov (United States)

Miao, Jinshui; Hu, Weida; Guo, Nan; Lu, Zhenyu; Liu, Xingqiang; Liao, Lei; Chen, Pingping; Jiang, Tao; Wu, Shiwei; Ho, Johnny C; Wang, Lin; Chen, Xiaoshuang; Lu, Wei

2015-02-25

Graphene is a promising candidate material for high-speed and ultra-broadband photodetectors. However, graphene-based photodetectors suffer from low photoreponsivity and I(light)/I(dark) ratios due to their negligible-gap nature and small optical absorption. Here, a new type of graphene/InAs nanowire (NW) vertically stacked heterojunction infrared photodetector is reported, with a large photoresponsivity of 0.5 AW(-1) and I(light)/I(dark) ratio of 5 × 10(2), while the photoresponsivity and I(light)/I(dark) ratio of graphene infrared photodetectors are 0.1 mAW(-1) and 1, respectively. The Fermi level (E(F)) of graphene can be widely tuned by the gate voltage owing to its 2D nature. As a result, the back-gated bias can modulate the Schottky barrier (SB) height at the interface between graphene and InAs NWs. Simulations further demonstrate the rectification behavior of graphene/InAs NW heterojunctions and the tunable SB controls charge transport across the vertically stacked heterostructure. The results address key challenges for graphene-based infrared detectors, and are promising for the development of graphene electronic and optoelectronic applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Infrared absorption and emission characteristics of interstellar PAHs [Polycyclic Aromatic Hydrocarbon

International Nuclear Information System (INIS)

Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

1986-01-01

The mid-infrared interstellar emission spectrum with features at 3050, 1610, 1300, 1150, and 885 cm -1 (3.28, 6.2, 7.7, 8.7 and 11.3 microns) is discussed in terms of the Polycyclic Aromatic Hydrocarbon (PAH) hypothesis. This hypothesis is based on the suggestive, but inconclusive comparison between the interstellar emission spectrum with the infrared absorption and Raman spectra of a few PAHs. The fundamental vibrations of PAHs and PAH-like species which determine the ir and Raman properties are discussed. Interstellar ir band emission is due to relaxation from highly vibrationally excited PAHs which have been excited by ultraviolet photons. The excitation/emission process is described in general and the ir fluorescence from one PAH, chrysene, is traced in detail. Generally, there is sufficient energy to populate several vibrational levels in each mode. Molecular vibrational potentials are anharmonic and emission from these higher levels will fall at lower frequencies and produce weak features to the red of the stronger fundamentals. This process is also described and can account for some spectroscopic details of the interstellar emission spectra previously unexplained. Analysis of the interstellar spectrum shows that PAHs containing between 20 and 30 carbon atoms are responsible for the emission. 43 refs., 11 figs

Infrared absorption and emission characteristics of interstellar PAHs (Polycyclic Aromatic Hydrocarbon)

Energy Technology Data Exchange (ETDEWEB)

Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

1986-01-01

The mid-infrared interstellar emission spectrum with features at 3050, 1610, 1300, 1150, and 885 cm/sup -1/ (3.28, 6.2, 7.7, 8.7 and 11.3 microns) is discussed in terms of the Polycyclic Aromatic Hydrocarbon (PAH) hypothesis. This hypothesis is based on the suggestive, but inconclusive comparison between the interstellar emission spectrum with the infrared absorption and Raman spectra of a few PAHs. The fundamental vibrations of PAHs and PAH-like species which determine the ir and Raman properties are discussed. Interstellar ir band emission is due to relaxation from highly vibrationally excited PAHs which have been excited by ultraviolet photons. The excitation/emission process is described in general and the ir fluorescence from one PAH, chrysene, is traced in detail. Generally, there is sufficient energy to populate several vibrational levels in each mode. Molecular vibrational potentials are anharmonic and emission from these higher levels will fall at lower frequencies and produce weak features to the red of the stronger fundamentals. This process is also described and can account for some spectroscopic details of the interstellar emission spectra previously unexplained. Analysis of the interstellar spectrum shows that PAHs containing between 20 and 30 carbon atoms are responsible for the emission. 43 refs., 11 figs.

Silicon waveguided components for the long-wave infrared region

Science.gov (United States)

Soref, Richard A.; Emelett, Stephen J.; Buchwald, Walter R.

2006-10-01

We propose that the operational wavelength of waveguided Si-based photonic integrated circuits and optoelectronic integrated circuits can be extended beyond the 1.55 µm telecom range into the wide infrared from 1.55 to 100 µm. The Si rib-membrane waveguide offers low-loss transmission from 1.2 to 6 µm and from 24 to 100 µm. This waveguide, which is compatible with Si microelectronics manufacturing, is constructed from silicon-on-insulator by etching away the oxide locally beneath the rib. Alternatively, low-loss waveguiding from 1.9 to 14.7 µm is assured by employing a crystal Ge rib grown directly upon the Si substrate. The Si-based hollow-core waveguide is an excellent device that minimizes loss due to silicon's 6-24 µm multi-phonon absorption. Here the rectangular air-filled core is surrounded by SiGe/Si multi-layer anti-resonant or Bragg claddings. The hollow channel offers less than 1.7 dB cm-1 loss from 1.2 to 100 µm. .

Detailed investigation of optoelectronic and microstructural properties of plasma polymerized cyclohexane thin films: Dependence on the radiofrequency power

International Nuclear Information System (INIS)

Manaa, C.; Bouaziz, L.; Lejeune, M.; Zellama, K.; Benlahsen, M.; Kouki, F.; Mejatty, M.; Bouchriha, H.

2015-01-01

Optical properties of polymerized cyclohexane films deposited by radiofrequency plasma enhanced chemical vapor deposition technique at different radiofrequency powers onto glass and silicon substrates, are studied and correlated with the microstructure of the films, using a combination of atomic force microscopy, Raman and Fourier Transformer Infrared spectroscopy and optical measurements. The optical constants such as refractive index n, dielectric permittivity ε and extinction k and absorption α coefficients, are extracted from transmission and reflection spectra through the commercial software CODE. These constants lead, by using common theoretical models as Cauchy, Lorentz, Tauc and single effective oscillator, to the determination of the static refractive index n s and permittivity ε s , the plasma frequency ω p , the carrier density to effective mass ratio N/m e * , the optical conductivity σ oc , the optical band gap E g and the oscillation and dispersion energies E 0 and E d , respectively. We find that n, ε s , ω p , N/m e * , E d , increase with radiofrequency power, while E g and E 0 decrease in the same range of power. These results are well correlated with those obtained from atomic force microscopy, Raman and infrared measurements. They also indicate that the increase of the radiofrequency power promotes the fragmentation of the precursor and increases the carbon C-sp 2 hybridization proportion, which results in an improvement of the optoelectronic properties of the films

High Aspect Ratio Plasmonic Nanotrench Structures with Large Active Surface Area for Label-Free Mid-Infrared Molecular Absorption Sensing

DEFF Research Database (Denmark)

Shkondin, Evgeniy; Repän, Taavi; Panah, Mohammad Esmail Aryaee

2018-01-01

. Here, we demonstrate the enhancement of infrared absorption in plasmonic trench structures that function as hyperbolic metamaterials. The metamaterial is composed of plasmonic trenches made of aluminum-doped zinc oxide. We use a 5 nm thick silica layer as a model analyte conformally coated around...

Tropospheric and total ozone columns over Paris (France measured using medium-resolution ground-based solar-absorption Fourier-transform infrared spectroscopy

Directory of Open Access Journals (Sweden)

C. Viatte

2011-10-01

Full Text Available Ground-based Fourier-transform infrared (FTIR solar absorption spectroscopy is a powerful remote sensing technique providing information on the vertical distribution of various atmospheric constituents. This work presents the first evaluation of a mid-resolution ground-based FTIR to measure tropospheric ozone, independently of stratospheric ozone. This is demonstrated using a new atmospheric observatory (named OASIS for "Observations of the Atmosphere by Solar absorption Infrared Spectroscopy", installed in Créteil (France. The capacity of the technique to separate stratospheric and tropospheric ozone is demonstrated. Daily mean tropospheric ozone columns derived from the Infrared Atmospheric Sounding Interferometer (IASI and from OASIS measurements are compared for summer 2009 and a good agreement of −5.6 (±16.1 % is observed. Also, a qualitative comparison between in-situ surface ozone measurements and OASIS data reveals OASIS's capacity to monitor seasonal tropospheric ozone variations, as well as ozone pollution episodes in summer 2009 around Paris. Two extreme pollution events are identified (on the 1 July and 6 August 2009 for which ozone partial columns from OASIS and predictions from a regional air-quality model (CHIMERE are compared following strict criteria of temporal and spatial coincidence. An average bias of 0.2%, a mean square error deviation of 7.6%, and a correlation coefficient of 0.91 is found between CHIMERE and OASIS, demonstrating the potential of a mid-resolution FTIR instrument in ground-based solar absorption geometry for tropospheric ozone monitoring.

Optical absorption and electrical properties of MPc (M =Fe, Cu, Zn)-TCNQ interfaces for optoelectronic applications

Science.gov (United States)

Sánchez Vergara, M. E.; Medrano Gallardo, D.; Vera Estrada, I. L.; Jiménez Sandoval, O.

2018-04-01

This research is related to the growth and characterization of doped molecular semiconductor metallophthalocyanine-tetracyanoquinodimethane (MPc-TCNQ) films, with M = Fe, Zn, Cu. FT-IR and Raman spectroscopies were employed to study the chemical interactions taking place in the MPc-TCNQ films. XRD was carried out to determine the crystalline structure present in the samples, due to the facility of the MPcs to be in alpha and/or beta phases. The thin films were analized by SEM and UV-vis spectroscopy in order to study their morphological and optical properties. The absorption spectra recorded in the UV-Vis region for the deposited samples showed two bands, namely the Q and Soret bands. The absorption coefficient (α) and photon energy (hν) were calculated from the UV-vis spectra, to in turn determine the optic activation energy in each film and its semiconductor behavior. The values obtained for direct transitions due to the crystallinity of the films were: 1.2, 1.4 and 2 eV for FePc-TCNQ (MMFe), ZnPc-TCNQ (MMZn) and CuPc-TCNQ (MMCu), respectively. Additionally, I-V characteristics have been obtained from fabricated glass/ITO/MM/Ag devices using ohmic contacts both after annealing. The electrical properties of the devices, e.g. carrier mobility and concentration of thermally generated holes, were extracted from the J-V characteristics. The results show that the conduction process is ohmic for the MMZn and MMCu devices, at low voltages, while at high voltages, a space-charge-limited conduction (SCLC) is present. The effect of temperature on conductivity was also measured in these samples and the lower thermal activation energy calculated was 0.37 eV for MMZn. Moreover, it was found that the temperature-dependent electric current is always higher for the MMZn device and suggests a semiconductor-like behavior with an important conductivity of the order of 103 S cm-1. Anyhow, in terms not only of electric properties, but also of optic behavior, the results suggest that

Organic optoelectronics:materials,devices and applications

Institute of Scientific and Technical Information of China (English)

LIU Yi; CUI Tian-hong

2005-01-01

The interest in organic materials for optoelectronic devices has been growing rapidly in the last two decades. This growth has been propelled by the exciting advances in organic thin films for displays, low-cost electronic circuits, etc. An increasing number of products employing organic electronic devices have become commercialized, which has stimulated the age of organic optoelectronics. This paper reviews the recent progress in organic optoelectronic technology. First, organic light emitting electroluminescent materials are introduced. Next, the three kinds of most important organic optoelectronic devices are summarized, including light emitting diode, organic photovoltaic cell, and photodetectors. The various applications of these devices are also reviewed and discussed in detail. Finally, the market and future development of optoelectronic devices are also demonstrated.

INFRARED ABSORPTION LINES TOWARD NGC 7538 IRS 1: ABUNDANCES OF H{sub 2}, H{sub 3}{sup +}, AND CO

Energy Technology Data Exchange (ETDEWEB)

Goto, Miwa [Universitäts-Sternwarte München, Scheinerstr. 1, D-81679 Munich (Germany); Geballe, T. R. [Gemini Observatory, 670 North A‘ohoku Place, Hilo, HI 96720 (United States); Usuda, Tomonori, E-mail: mgoto@usm.lmu.de, E-mail: tgeballe@gemini.edu, E-mail: usuda@naoj.org [Subaru Telescope, 650 North A‘ohoku Place, Hilo, HI 96720 (United States)

2015-06-10

We report high-resolution near-infrared absorption spectroscopy of H{sub 2}, H{sub 3}{sup +}, and CO toward the young high mass object NGC 7538 IRS 1. The v = 1–0 H{sub 2} S(0) line and lines in the CO v = 2–0 band were detected; the v = 1–0 H{sub 2} S(1) line and the v = 1–0 H{sub 3}{sup +} lines [R(1, 1){sup l}, R(1, 0), R(1, 1){sup u}] were not detected. The line of sight traverses two clouds, with temperatures 45 and 259 K and with roughly equal column densities of CO. Assuming that H{sub 2} is at the same temperature as CO and that the two species are uniformly mixed, [H{sub 2}]/[CO] = 3600 ± 1200. NGC 7538 is the most distant object from the Galactic center for which [H{sub 2}]/[CO] has been directly measured using infrared absorption spectroscopy.

N-Annulated perylene-substituted and fused porphyrin dimers with intense near-infrared one-photon and two-photon absorption

KAUST Repository

Luo, Jie

2015-01-21

Fusion of two N-annulated perylene (NP) units with a fused porphyrin dimer along the S0-S1 electronic transition moment axis has resulted in new near-infrared (NIR) dyes 1a/1b with very intense absorption (ε>1.3×105M-1cm-1) beyond 1250nm. Both compounds displayed moderate NIR fluorescence with fluorescence quantum yields of 4.4×10-6 and 6.0×10-6 for 1a and 1b, respectively. The NP-substituted porphyrin dimers 2a/2b have also been obtained by controlled oxidative coupling and cyclodehydrogenation, and they showed superimposed absorptions of the fused porphyrin dimer and the NP chromophore. The excited-state dynamics of all of these compounds have been studied by femtosecond transient absorption measurements, which revealed porphyrin dimer-like behaviour. These new chromophores also exhibited good nonlinear optical susceptibility with large two-photon absorption cross-sections in the NIR region due to extended π-conjugation. Time-dependent density functional theory calculations have been performed to aid our understanding of their electronic structures and absorption spectra.

Optoelectronic Mounting Structure

Science.gov (United States)

Anderson, Gene R.; Armendariz, Marcelino G.; Baca, Johnny R. F.; Bryan, Robert P.; Carson, Richard F.; Chu, Dahwey; Duckett, III, Edwin B.; McCormick, Frederick B.; Peterson, David W.; Peterson, Gary D.; Reber, Cathleen A.; Reysen, Bill H.

2004-10-05

An optoelectronic mounting structure is provided that may be used in conjunction with an optical transmitter, receiver or transceiver module. The mounting structure may be a flexible printed circuit board. Thermal vias or heat pipes in the head region may transmit heat from the mounting structure to the heat spreader. The heat spreader may provide mechanical rigidity or stiffness to the heat region. In another embodiment, an electrical contact and ground plane may pass along a surface of the head region so as to provide an electrical contact path to the optoelectronic devices and limit electromagnetic interference. In yet another embodiment, a window may be formed in the head region of the mounting structure so as to provide access to the heat spreader. Optoelectronic devices may be adapted to the heat spreader in such a manner that the devices are accessible through the window in the mounting structure.

Infrared study of the absorption edge of β-InN films grown on GaN/MgO structures

Science.gov (United States)

Pérez-Caro, M.; Rodríguez, A. G.; Vidal, M. A.; Navarro-Contreras, H.

2010-07-01

Infrared optical studies were carried out in a group of cubic InN samples grown by gas source molecular beam epitaxy on MgO (001) substrates. Room temperature (RT) reflectance and low-temperature (LT) transmittance measurements were performed by using fast Fourier transform infrared spectrometry. Reflectance fittings allowed to establish that β-InN films have large free-carrier concentrations present (>1019 cm-3), a result that is corroborated by Hall effect measurements. Each sample explored exhibited a different optical absorption edge. The Varshni parameters that describe adequately the optical absorption edge responses with temperature are obtained for the set of samples studied. The observed temperatures changes, from LT to RT, are the lowest reported for III-V semiconductor binary compounds. The temperature coefficient of the conduction band depends on the strength of the electron-phonon interaction (e-ph-i), as well as on the thermal expansion. It has been predicted that cubic InN has one of the smallest e-ph-i of all III-V compounds, which is corroborated by these results. The variation in values of absorption edges is clearly consistent with the Burstein-Moss and band renormalization effects, produced by high free electron concentrations. It is shown that the conduction band in β-InN, analogous to wurtzite InN, follows a nonparabolic behavior.

Infrared study of the absorption edge of β-InN films grown on GaN/MgO structures

International Nuclear Information System (INIS)

Perez-Caro, M.; Rodriguez, A. G.; Vidal, M. A.; Navarro-Contreras, H.

2010-01-01

Infrared optical studies were carried out in a group of cubic InN samples grown by gas source molecular beam epitaxy on MgO (001) substrates. Room temperature (RT) reflectance and low-temperature (LT) transmittance measurements were performed by using fast Fourier transform infrared spectrometry. Reflectance fittings allowed to establish that β-InN films have large free-carrier concentrations present (>10 19 cm -3 ), a result that is corroborated by Hall effect measurements. Each sample explored exhibited a different optical absorption edge. The Varshni parameters that describe adequately the optical absorption edge responses with temperature are obtained for the set of samples studied. The observed temperatures changes, from LT to RT, are the lowest reported for III-V semiconductor binary compounds. The temperature coefficient of the conduction band depends on the strength of the electron-phonon interaction (e-ph-i), as well as on the thermal expansion. It has been predicted that cubic InN has one of the smallest e-ph-i of all III-V compounds, which is corroborated by these results. The variation in values of absorption edges is clearly consistent with the Burstein-Moss and band renormalization effects, produced by high free electron concentrations. It is shown that the conduction band in β-InN, analogous to wurtzite InN, follows a nonparabolic behavior.

Infrared line intensities of chlorine monoxide

Science.gov (United States)

Kostiuk, T.; Faris, J. L.; Mumma, M. J.; Deming, D.; Hillman, J. J.

1986-01-01

Absolute infrared line intensities of several ClO lines in the rotational-vibrational (1-0) band were measured using infrared heterodyne spectroscopy near 12 microns. A measurement technique using combined ultraviolet absorption and infrared line measurements near 9.5 microns and 12 microns permitted an accurate determination of the column densities of O3 and ClO in the absorption cell and thus improved ClO line intensities. Results indicate ClO line and band intensities approximately 2.4 times lower than previous experimental results. Effects of possible failure of local thermodynamic equilibrium conditions in the absorption cell and the implication of the results for stratospheric ClO measurements in the infrared are discussed.

Broadband perfect infrared absorption by tuning epsilon-near-zero and epsilon-near-pole resonances of multilayer ITO nanowires.

Science.gov (United States)

Zhou, Kun; Cheng, Qiang; Song, Jinlin; Lu, Lu; Jia, Zhihao; Li, Junwei

2018-01-01

We numerically investigate the broadband perfect infrared absorption by tuning epsilon-near-zero (ENZ) and epsilon-near-pole (ENP) resonances of multilayer indium tin oxide nanowires (ITO NWs). The monolayer ITO NWs array shows intensive absorption at ENZ and ENP wavelengths for p polarization, while only at the ENP wavelength for s polarization. Moreover, the ENP resonances are almost omnidirectional and the ENZ resonances are angularly dependent. Therefore, the absorption bandwidth is broader for p polarization than that for s polarization when polarized waves are incident obliquely. The ENZ resonances can be tuned by altering the doping concentration and volume filling factor of ITO NWs. However, the ENP resonances only can be tuned by changing the doping concentration of ITO NWs, and volume filling factor impacts little on the ENP resonances. Based on the strong absorption properties of each layer at their own ENP and ENZ resonances, the tuned absorption of the bilayer ITO NWs with the different doping concentrations can be broader and stronger. Furthermore, multilayer ITO NWs can achieve broadband perfect absorption by controlling the doping concentration, volume filling factor, and length of the NWs in each layer. This study has the potential to apply to applications requiring efficient absorption and energy conversion.

Enhanced absorption of graphene in the visible region by use of plasmonic nanostructures

DEFF Research Database (Denmark)

Hashemi, Mahdieh; Farzad, Mahmood Hosseini; Mortensen, N. Asger

2013-01-01

Low absorption of graphene in the visible range of the spectrum makes it difficult to uniquely benefit from this material in ultra-fast optoelectronic applications. We numerically propose to utilize patterned metallic nanostructures to increase light absorption in single-layer graphene. Simulation...... results show that excitation of surface plasmon resonances in the metallic nanostructures significantly enhances the local electromagnetic field near the graphene layer, therefore leading to a dramatic enhancement of the absorption in the graphene layer itself. Broadband high optical absorption can...

Environmental Temperature Effect on the Far-Infrared Absorption Features of Aromatic-Based Titan's Aerosol Analogs

Science.gov (United States)

Gautier, Thomas; Trainer, Melissa G.; Loeffler, Mark J.; Sebree, Joshua A.; Anderson, Carrie M.

2016-01-01

Benzene detection has been reported in Titans atmosphere both in the stratosphere at ppb levels by remote sensing and in the thermosphere at ppm levels by the Cassini's Ion and Neutral Mass Spectrometer. This detection supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titans atmospheric chemistry, especially in the formation of aerosols. Indeed, aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation. It has been shown recently that aerosol analogs produced from a gas mixture containing a low concentration of aromatic and/or heteroaromatic molecules (benzene, naphthalene, pyridine, quinoline and isoquinoline) have spectral signatures below 500/cm, a first step towards reproducing the aerosol spectral features observed by Cassini's Composite InfraRed Spectrometer (CIRS) in the far infrared. In this work we investigate the influence of environmental temperature on the absorption spectra of such aerosol samples, simulating the temperature range to which aerosols, once formed, are exposed during their transport through Titans stratosphere. Our results show that environmental temperature does not have any major effect on the spectral shape of these aerosol analogs in the far-infrared, which is consistent with the CIRS observations.

A low noise preamplifier with optoelectronic overload protection for radioactivity measurement

International Nuclear Information System (INIS)

Sephton, J.P.; Williams, J.M.; Johansson, L.C.; Philips, H.C.

2012-01-01

Pulses from detectors used for radioactivity measurement can vary in size by several orders of magnitude. Large pulses will lead to saturation at the preamplifier output and extension of the pulse length. As a consequence, the dead time of the system increases and pulses may be lost. Electronic design techniques employed to protect against overloading tend to increase the amplifier noise level. However, an optoelectronic method of overload protection has been devised which has only a negligible effect on noise. An infrared light emitting diode interfaced to the output of the preamplifier is linked by fibre optic cable to an ultra-low leakage photodiode at the input. The conduction of the photodiode increases with the amplitude of the preamplifier output signal. Excess current is thereby prevented from entering the preamplifier and causing saturation. The preamplifier has been tested on 4π beta–gamma and gas counting systems and found to give good protection against overloading. - Highlights: ► A preamplifier for radioactivity measurements has been developed. ► Low noise. ► Current sensitive. ► Optoelectronic overload protection.

Optoelectronic investigation of nanodiamond interactions with human blood

Science.gov (United States)

Ficek, M.; Wróbel, M. S.; Wasowicz, M.; Jedrzejewska-Szczerska, M.

2016-03-01

We present optoelectronic investigation of in vitro interactions of whole human blood with different nanodiamond biomarkers. Plasmo-chemical modifications of detonation nanodiamond particles gives the possibility for controlling their surface for biological applications. Optical investigations reveal the biological activity of nanodiamonds in blood dependent on its surface termination. We compare different types of nanodiamonds: commercial non-modified detonation nanodiamonds, and nanodiamonds modified by MW PACVD method with H2-termination, and chemically modified nanodiamond with O2-termination. The absorption spectra, and optical microscope investigations were conducted. The results indicate haemocompatibility of non-modified detonation nanodiamond as well as modified nanodiamonds, which enables their application for drug delivery, as well as sensing applications.

NuSTAR reveals an intrinsically x-ray weak broad absorption line quasar in the ultraluminous infrared galaxy Markarian 231

DEFF Research Database (Denmark)

Teng, Stacy H.; Brandt, W. N.; Harrison, F. A.

2014-01-01

-ionization broad absorption line quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may...

Infrared absorption in PbTe single crystals

International Nuclear Information System (INIS)

Kudykina, T.A.

1982-01-01

A group-theoretical analysis is conducted to select rules for optical transitions between bands in PbTe single crystals. It is shown that transitions between valence bands which are near a forbidden band are also forbidden. The extra absorption observed in p-PbTe and p-Pbsub(1-x)Snsub(x)Te in the region between the self-absorption edge and the free-carrier absorption edge is probably connected with transitions between one of valence bands and the p-state of the impurity

Optical modeling based on mean free path calculations for quantum dot phosphors applied to optoelectronic devices.

Science.gov (United States)

Shin, Min-Ho; Kim, Hyo-Jun; Kim, Young-Joo

2017-02-20

We proposed an optical simulation model for the quantum dot (QD) nanophosphor based on the mean free path concept to understand precisely the optical performance of optoelectronic devices. A measurement methodology was also developed to get the desired optical characteristics such as the mean free path and absorption spectra for QD nanophosphors which are to be incorporated into the simulation. The simulation results for QD-based white LED and OLED displays show good agreement with the experimental values from the fabricated devices in terms of spectral power distribution, chromaticity coordinate, CCT, and CRI. The proposed simulation model and measurement methodology can be applied easily to the design of lots of optoelectronics devices using QD nanophosphors to obtain high efficiency and the desired color characteristics.

Latest developments in GaN-based quantum devices for infrared optoelectronics

OpenAIRE

Monroy, Eva; Guillot, Fabien; Leconte, Sylvain; Nevou, Laurent; Doyennette, Laeticia; Tchernycheva, Maria; Julien, François H.; Baumann, Esther; Giorgetta, Fabrizio R.; Hofstetter, Daniel

2011-01-01

In this work, we summarize the latest progress in intersubband devices based on GaN/AlN nanostructures for operation in the near-infrared. We first discuss the growth and characterization of ultra-thin GaN/AlN quantum well and quantum dot superlattices by plasma-assisted molecular-beam epitaxy. Then, we present the performance of nitride-based infrared photodetectors and electro-optical modulators operating at 1.55 μm. Finally, we discuss the progress towards intersubband light emitters, incl...

An applicable approach for extracting human heart rate and oxygen saturation during physical movements using a multi-wavelength illumination optoelectronic sensor system

Science.gov (United States)

Alharbi, Samah; Hu, Sijung; Mulvaney, David; Blanos, Panagiotis

2018-02-01

The ability to gather physiological parameters such as heart rate (HR) and oxygen saturation (SpO2%) during physical movement allows to continuously monitor personal health status without disrupt their normal daily activities. Photoplethysmography (PPG) based pulse oximetry and similar principle devices are unable to extract the HR and SpO2% reliably during physical movement due to interference in the signals that arise from motion artefacts (MAs). In this research, a flexible reflectance multi-wavelength optoelectronic patch sensor (OEPS) has been developed to overcome the susceptibility of conventional pulse oximetry readings to MAs. The OEPS incorporates light embittered diodes as illumination sources with four different wavelengths, e.g. green, orange, red, and infrared unlike the conventional pulse oximetry devices that normally measure the skin absorption of only two wavelengths (red and infrared). The additional green and orange wavelengths were found to be distinguish to the absorption of deoxyhemoglobin (RHb) and oxyhemoglobin (HbO2). The reliability of extracting physiological parameters from the green and orange wavelengths is due to absorbed near to the surface of the skin, thereby shortening the optical path and so effectively reducing the influence of physical movements. To compensate of MAs, a three-axis accelerometer was used as a reference with help of adaptive filter to reduce MAs. The experiments were performed using 15 healthy subjects aged 20 to 30. The primary results show that there are no significant difference of heart rate and oxygen saturation measurements between commercial devices and OEPS Green (r=0.992), Orange(r=0.984), Red(r=0.952) and IR(r=0.97) and SpO2% (r = 0.982, p = 0.894).

Investigation, study and practice of optoelectronic MOOCs

Science.gov (United States)

Shi, Jianhua; Liu, Wei; Lei, Bing; Yao, Tianfu; Fu, Sihua

2017-08-01

MOOC(Massive Open Online Course) is a new teaching model that has been springing up since 2012. The typical characters are short teaching video, massive learners, flexible place and time to study, etc. Although MOOC is very popular now, opto-electronic MOOCs are not much enough to meet the need of online learners. In this paper, the phylogeny, the current situation and the characters of MOOC were described, the most famous MOOCs' websites, such as Udacity, Coursera, edX, Chinese College MOOC, xuetangx, were introduced, the opto-electronic MOOCs come from these famous MOOCs' website were investigated extensively and studied deeply, the "Application of Opto-electronic Technology MOOC" which was established by our group is introduced, and some conclusions are obtained. These conclusions can give some suggestions to the online learners who are interested in opto-electronic and the teachers who are teaching the opto-electronic curriculums. The preparation of "Opto-electronic Technology MOOC" is described in short.

An Opto-Electronic Sensor for Detecting Soil Microarthropods and Estimating Their Size in Field Conditions

Directory of Open Access Journals (Sweden)

Csongor I. Gedeon

2017-08-01

Full Text Available Methods to estimate density of soil-dwelling arthropods efficiently, accurately and continuously are critical for investigating soil biological activity and evaluating soil management practices. Soil-dwelling arthropods are currently monitored manually. This method is invasive, and time- and labor-consuming. Here we describe an infrared opto-electronic sensor for detection of soil microarthropods in the size range of 0.4–10 mm. The sensor is built in a novel microarthropod trap designed for field conditions. It allows automated, on-line, in situ detection and body length estimation of soil microarthropods. In the opto-electronic sensor the light source is an infrared LED. Two plano-convex optical lenses are placed along the virtual optical axis. One lens on the receiver side is placed between the observation space at 0.5–1 times its focal length from the sensor, and another emitter side lens is placed between the observation space and the light source in the same way. This paper describes the setup and operating mechanism of the sensor and the control unit, and through basic tests it demonstrates its potential in automated detection of soil microarthropods. The sensor may be used for monitoring activities, especially for remote observation activities in soil and insect ecology or pest control.

Controlling microstructure of pentacene derivatives by solution processing: impact of structural anisotropy on optoelectronic properties.

Science.gov (United States)

James, David T; Frost, Jarvist M; Wade, Jessica; Nelson, Jenny; Kim, Ji-Seon

2013-09-24

The consideration of anisotropic structural properties and their impact on optoelectronic properties in small-molecule thin films is vital to understand the performance of devices incorporating crystalline organic semiconductors. Here we report on the important relationship between structural and optoelectronic anisotropy in aligned, functionalized-pentacene thin films fabricated using the solution-based zone-casting technique. The microstructure of thin films composed of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) and 6,13-bis(triethylsilylethynyl)pentacene (TES-pentacene) is systematically controlled by varying the casting speed. By controlling the structural alignment, we were able to experimentally decouple, for the first time in these films, an intramolecular absorption transition dipole (at ∼440 nm) oriented close to the pentacene short axis and an intermolecular absorption transition dipole (at ∼695 nm) oriented predominantly along the conjugated pentacene-pentacene core stacking axis (crystallographic a-axis) in both films. Using the intermolecular absorption as a signature for intermolecular delocalization, much higher optical dichroism was obtained in TES-pentacene (16 ± 6) than TIPS-pentacene (3.2 ± 0.1), which was attributed to the 1D packing structure of TES-pentacene compared to the 2D packing structure of TIPS-pentacene. This result was also supported by field-effect mobility anisotropy measurements of the films, with TES-pentacene exhibiting a higher anisotropy (∼21-47, depending on the casting speed) than TIPS-pentacene (∼3-10).

Two-colour mid-infrared absorption in an InAs/GaSb-based type II and broken-gap quantum well

International Nuclear Information System (INIS)

Wei, X F; Xu, W; Zeng, Z

2007-01-01

We examine contributions from different transition channels to optical absorption in an InAs/GaSb-based type II and broken-gap quantum well (QW). In such a structure, because both electron and hole subbands are occupied by the conducting carriers, new channels open up for electronic transition via intra- and inter-layer scattering mechanisms. We find that two absorption peaks can be observed through inter-subband transitions within the same material layer. The absorption induced by the inter-layer transition is rather weak due to a small overlap of electron and hole wavefunctions. The results suggest that InAs/GaSb-based type II and broken-gap QWs can be employed as two-colour photodetectors working at mid-infrared bandwidth at relatively high temperatures up to room-temperature

Influence of temperature on water and aqueous glucose absorption spectra in the near- and mid-infrared regions at physiologically relevant temperatures

DEFF Research Database (Denmark)

Jensen, P.S.; Bak, J.; Andersson-Engels, S.

2003-01-01

transmission cell controlled within 0.02 degreesC. Pathlengths of 50 mum and 0.4 mm were used in the mid- and near-infrared spectral region, respectively. Difference spectra were used to determine the effect of temperature on the water spectra quantitatively. These spectra were obtained by subtracting the 37...... degreesC water spectrum from the spectra measured at other temperatures. The difference spectra reveal that the effect of temperature is highest in the vicinity of the strong absorption bands, with a number of isosbestic points with no temperature dependence and relatively flat plateaus in between......Near- and mid-infrared absorption spectra of pure water and aqueous 1.0 g/dL glucose solutions in the wavenumber range 8000-950 cm(-1) were measured in the temperature range 30-42 C in steps of 2 degreesC. Measurements were carried out with an FT-IR spectrometer and a variable pathlength...

Infrared Absorption Spectroscopy and Chemical Kinetics of Free Radicals, Final Technical Report

Science.gov (United States)

Curl, Robert F.; Glass, Graham P.

2004-11-01

This research was directed at the detection, monitoring, and study of the chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. Work on the reaction of OH with acetaldehyde has been completed and published and work on the reaction of O({sup 1}D) with CH{sub 4} has been completed and submitted for publication. In the course of our investigation of branching ratios of the reactions of O({sup 1}D) with acetaldehyde and methane, we discovered that hot atom chemistry effects are not negligible at the gas pressures (13 Torr) initially used. Branching ratios of the reaction of O({sup 1}D) with CH{sub 4} have been measured at a tenfold higher He flow and fivefold higher pressure.

FeNi3/indium tin oxide (ITO) composite nanoparticles with excellent microwave absorption performance and low infrared emissivity

International Nuclear Information System (INIS)

Fu, Li-Shun; Jiang, Jian-Tang; Zhen, Liang; Shao, Wen-Zhu

2013-01-01

Highlights: ► Electrical conductivity and infrared emissivity can be controlled by ITO content. ► The infrared emissivity is the lowest when the mole ratio of In:Sn in sol is 9:1. ► The permittivity in microwave band can be controlled by the electrical conductivity. ► EMA performance is significantly influenced by the content of ITO phase. ► FeNi 3 /ITO composite particles are suitable for both infrared and radar camouflage. - Abstract: FeNi 3 /indium tin oxide (ITO) composite nanoparticles were synthesized by a self-catalyzed reduction method and a sol–gel process. The dependence of the content of ITO phase with the mole ratios of In:Sn of different sols was investigated. The relation between the electrical conductivity, infrared emissivity of FeNi 3 /ITO composite nanoparticles and the content of ITO phase was discussed. Electromagnetic wave absorption (EMA) performance of products was evaluated by using transmission line theory. It was found that EMA performance including the intensity and the location of effective band is significantly dependent on the content of ITO phase. The low infrared emissivity and superior EMA performance of FeNi 3 /ITO composite nanoparticles can be both achieved when the mole ratio of In:Sn in sol is 9:1.

Deformable paper origami optoelectronic devices

KAUST Repository

He, Jr-Hau

2017-01-19

Deformable optoelectronic devices are provided, including photodetectors, photodiodes, and photovoltaic cells. The devices can be made on a variety of paper substrates, and can include a plurality of fold segments in the paper substrate creating a deformable pattern. Thin electrode layers and semiconductor nanowire layers can be attached to the substrate, creating the optoelectronic device. The devices can be highly deformable, e.g. capable of undergoing strains of 500% or more, bending angles of 25° or more, and/or twist angles of 270° or more. Methods of making the deformable optoelectronic devices and methods of using, e.g. as a photodetector, are also provided.

Optoelectronic sensor device for monitoring ethanol concentration in winemaking applications

Science.gov (United States)

Jiménez-Márquez, F.; Vázquez, J.; Úbeda, J.; Rodríguez-Rey, J.; Sánchez-Rojas, J. L.

2015-05-01

The supervision of key variables such as sugar, alcohol, released CO2 and microbiological evolution in fermenting grape must is of great importance in the winemaking industry. However, the fermentation kinetics is assessed by monitoring the evolution of the density as it varies during a fermentation, since density is an indicator of the total amount of sugars, ethanol and glycerol. Even so, supervising the fermentation process is an awkward and non-comprehensive task, especially in wine cellars where production rates are massive, and enologists usually measure the density of the extracted samples from each fermentation tank manually twice a day. This work aims at the design of a fast, low-cost, portable and reliable optoelectronic sensor for measuring ethanol concentration in fermenting grape must samples. Different sets of model solutions, which contain ethanol, fructose, glucose, glycerol dissolved in water and emulate the grape must composition at different stages of the fermentation, were prepared both for calibration and validation. The absorption characteristics of these model solutions were analyzed by a commercial spectrophotometer in the NIR region, in order to identify key wavelengths from which valuable information regarding the sample composition can be extracted. Finally, a customized optoelectronic prototype based on absorbance measurements at two wavelengths belonging to the NIR region was designed, fabricated and successfully tested. The system, whose optoelectronics is reduced after a thorough analysis to only two LED lamps and their corresponding paired photodiodes operating at 1.2 and 1.3 μm respectively, calculates the ethanol content by a multiple linear regression.

Surface structure, optoelectronic properties and charge transport in ZnO nanocrystal/MDMO-PPV multilayer films.

Science.gov (United States)

Lian, Qing; Chen, Mu; Mokhtar, Muhamad Z; Wu, Shanglin; Zhu, Mingning; Whittaker, Eric; O'Brien, Paul; Saunders, Brian R

2018-05-07

Blends of semiconducting nanocrystals and conjugated polymers continue to attract major research interest because of their potential applications in optoelectronic devices, such as solar cells, photodetectors and light-emitting diodes. In this study we investigate the surface structure, morphological and optoelectronic properties of multilayer films constructed from ZnO nanocrystals (NCs) and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV). The effects of layer number and ZnO concentration (C ZnO ) used on the multilayer film properties are investigated. An optimised solvent blend enabled well-controlled layers to be sequentially spin coated and the construction of multilayer films containing six ZnO NC (Z) and MDMO-PPV (M) layers (denoted as (ZM) 6 ). Contact angle data showed a strong dependence on C ZnO and indicated distinct differences in the coverage of MDMO-PPV by the ZnO NCs. UV-visible spectroscopy showed that the MDMO-PPV absorption increased linearly with the number of layers in the films and demonstrates highly tuneable light absorption. Photoluminescence spectra showed reversible quenching as well as a surprising red-shift of the MDMO-PPV emission peak. Solar cells were constructed to probe vertical photo-generated charge transport. The measurements showed that (ZM) 6 devices prepared using C ZnO = 14.0 mg mL -1 had a remarkably high open circuit voltage of ∼800 mV. The device power conversion efficiency was similar to that of a control bilayer device prepared using a much thicker MDMO-PPV layer. The results of this study provide insight into the structure-optoelectronic property relationships of new semiconducting multilayer films which should also apply to other semiconducting NC/polymer combinations.

Fusion of Ultraviolet-Visible and Infrared Transient Absorption Spectroscopy Data to Model Ultrafast Photoisomerization.

Science.gov (United States)

Debus, Bruno; Orio, Maylis; Rehault, Julien; Burdzinski, Gotard; Ruckebusch, Cyril; Sliwa, Michel

2017-08-03

Ultrafast photoisomerization reactions generally start at a higher excited state with excess of internal vibrational energy and occur via conical intersections. This leads to ultrafast dynamics which are difficult to investigate with a single transient absorption spectroscopy technique, be it in the ultraviolet-visible (UV-vis) or infrared (IR) domain. On one hand, the information available in the UV-vis domain is limited as only slight spectral changes are observed for different isomers. On the other hand, the interpretation of vibrational spectra is strongly hindered by intramolecular relaxation and vibrational cooling. These limitations can be circumvented by fusing UV-vis and IR transient absorption spectroscopy data in a multiset multivariate curve resolution analysis. We apply this approach to describe the spectrodynamics of the ultrafast cis-trans photoisomerization around the C-N double bond observed for aromatic Schiff bases. Twisted intermediate states could be elucidated, and isomerization was shown to occur through a continuous complete rotation. More broadly, data fusion can be used to rationalize a vast range of ultrafast photoisomerization processes of interest in photochemistry.

Topological insulator infrared pseudo-bolometer with polarization sensitivity

Energy Technology Data Exchange (ETDEWEB)

Sharma, Peter Anand

2017-10-25

Topological insulators can be utilized in a new type of infrared photodetector that is intrinsically sensitive to the polarization of incident light and static magnetic fields. The detector isolates single topological insulator surfaces and allows light collection and exposure to static magnetic fields. The wavelength range of interest is between 750 nm and about 100 microns. This detector eliminates the need for external polarization selective optics. Polarization sensitive infrared photodetectors are useful for optoelectronics applications, such as light detection in environments with low visibility in the visible wavelength regime.

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)

Band engineering of amorphous silicon ruthenium thin film and its near-infrared absorption enhancement combined with nano-holes pattern on back surface of silicon substrate

Energy Technology Data Exchange (ETDEWEB)

Guo, Anran; Zhong, Hao [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Li, Wei, E-mail: wli@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Gu, Deen; Jiang, Xiangdong [School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Jiang, Yadong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

2016-10-30

Highlights: • The increase of Ru concentration leads to a narrower bandgap of a-Si{sub 1-x}Ru{sub x} thin film. • The absorption coefficient of a-Si{sub 1-x}Ru{sub x} is higher than that of SiGe. • A double-layer absorber comprising of a-Si{sub 1-x}Ru{sub x} film and Si nano-holes layer is achieved. - Abstract: Silicon is widely used in semiconductor industry but has poor performance in near-infrared photoelectronic devices because of its bandgap limit. In this study, a narrow bandgap silicon rich semiconductor is achieved by introducing ruthenium (Ru) into amorphous silicon (a-Si) to form amorphous silicon ruthenium (a-Si{sub 1-x}Ru{sub x}) thin films through co-sputtering. The increase of Ru concentration leads to an enhancement of light absorption and a narrower bandgap. Meanwhile, a specific light trapping technique is employed to realize high absorption of a-Si{sub 1-x}Ru{sub x} thin film in a finite thickness to avoid unnecessary carrier recombination. A double-layer absorber comprising of a-Si{sub 1-x}Ru{sub x} thin film and silicon random nano-holes layer is formed on the back surface of silicon substrates, and significantly improves near-infrared absorption while the leaky light intensity is less than 5%. This novel absorber, combining narrow bandgap thin film with light trapping structure, may have a potential application in near-infrared photoelectronic devices.

Solar absorption surface panel

Science.gov (United States)

Santala, Teuvo J.

1978-01-01

A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

Au-rich filamentary behavior and associated subband gap optical absorption in hyperdoped Si

Science.gov (United States)

Yang, W.; Akey, A. J.; Smillie, L. A.; Mailoa, J. P.; Johnson, B. C.; McCallum, J. C.; Macdonald, D.; Buonassisi, T.; Aziz, M. J.; Williams, J. S.

2017-12-01

Au-hyperdoped Si, synthesized by ion implantation and pulsed laser melting, is known to exhibit a strong sub-band gap photoresponse that scales monotonically with the Au concentration. However, there is thought to be a limit to this behavior since ultrahigh Au concentrations (>1 ×1020c m-3 ) are expected to induce cellular breakdown during the rapid resolidification of Si, a process that is associated with significant lateral impurity precipitation. This work shows that the cellular morphology observed in Au-hyperdoped Si differs from that in conventional, steady-state cellular breakdown. In particular, Rutherford backscattering spectrometry combined with channeling and transmission electron microscopy revealed an inhomogeneous Au distribution and a subsurface network of Au-rich filaments, within which the Au impurities largely reside on substitutional positions in the crystalline Si lattice, at concentrations as high as ˜3 at. %. The measured substitutional Au dose, regardless of the presence of Au-rich filaments, correlates strongly with the sub-band gap optical absorptance. Upon subsequent thermal treatment, the supersaturated Au forms precipitates, while the Au substitutionality and the sub-band gap optical absorption both decrease. These results offer insight into a metastable filamentary regime in Au-hyperdoped Si that has important implications for Si-based infrared optoelectronics.

An infrared view of high Tc superconductors

International Nuclear Information System (INIS)

Tanner, D.B.; Timusk, T.; McMaster Univ., Hamilton, ON

1989-01-01

Studies of the infrared properties of the high T c superconductors are reviewed, with particular emphasis on attempts to determine the energy gap by far infrared spectroscopy and on the properties of the strong absorption that occurs in the mid infrared. The authors argue that this mid-infrared absorption is a direct particle-hole excitation rather than a Holstein emission process. In addition, they conclude that although the energy gap is not easily observed, several recent experiments place it in the weak to moderate strong coupling range

[Infrared spectral analysis for calcined borax].

Science.gov (United States)

Zhao, Cui; Ren, Li-Li; Wang, Dong; Zhou, Ping; Zhang, Qian; Wang, Bo-Tao

2011-08-01

To valuate the quality of calcined borax which is sold in the market, 18 samples of calcined borax were studied using the Fourier transform infrared, and samples with different water content were selected and analyzed. Then, the results of analysis were used to evaluate the quality of calcined borax. Results show that the infrared spectra of calcined borax include OH vibration, BO3(-3) vibration and BO4(5-) vibration absorption bands. The position and width of OH vibration absorption band depend on the level of water content, and the more the water content, the wider the absorption band. The number of BO3(3-) vibration and BO4(5-) vibration bands also depend on the level of water content, and the more the water content, and the stronger the hydrogen bond and the lower the symmetry of B atoms, the more the number of infrared absorption peaks. It was concluded that because the quality of calcined borax has direct correlation with water content, the infrared spectroscopy is an express and objective approach to quality analysis and evaluation of calcined borax.

Photonic Structure-Integrated Two-Dimensional Material Optoelectronics

Directory of Open Access Journals (Sweden)

Tianjiao Wang

2016-12-01

Full Text Available The rapid development and unique properties of two-dimensional (2D materials, such as graphene, phosphorene and transition metal dichalcogenides enable them to become intriguing candidates for future optoelectronic applications. To maximize the potential of 2D material-based optoelectronics, various photonic structures are integrated to form photonic structure/2D material hybrid systems so that the device performance can be manipulated in controllable ways. Here, we first introduce the photocurrent-generation mechanisms of 2D material-based optoelectronics and their performance. We then offer an overview and evaluation of the state-of-the-art of hybrid systems, where 2D material optoelectronics are integrated with photonic structures, especially plasmonic nanostructures, photonic waveguides and crystals. By combining with those photonic structures, the performance of 2D material optoelectronics can be further enhanced, and on the other side, a high-performance modulator can be achieved by electrostatically tuning 2D materials. Finally, 2D material-based photodetector can also become an efficient probe to learn the light-matter interactions of photonic structures. Those hybrid systems combine the advantages of 2D materials and photonic structures, providing further capacity for high-performance optoelectronics.

Observation of infrared absorption of InAs quantum dot structures in AlGaAs matrix toward high-efficiency solar cells

Science.gov (United States)

Yoshikawa, Hirofumi; Watanabe, Katsuyuki; Kotani, Teruhisa; Izumi, Makoto; Iwamoto, Satoshi; Arakawa, Yasuhiko

2018-06-01

In accordance with the detailed balance limit model of single-intermediate-band solar cells (IBSCs), the optimum matrix bandgap and IB–conduction band (CB) energy gap are ∼1.9 and 0.7 eV, respectively. We present the room-temperature polarized infrared absorption of 20 stacked InAs quantum dot (QD) structures in the Al0.32Ga0.68As matrix with a bandgap of ∼1.9 eV for the design of high-efficiency IBSCs by using a multipass waveguide geometry. We find that the IB–CB absorption is almost independent of the light polarization, and estimate the magnitude of the absorption per QD layer to be ∼0.01%. We also find that the IB–CB absorption edge of QD structures with a wide-gap matrix is ∼0.41 eV. These results indicate that both the significant increase in the magnitude of IB–CB absorption and the lower energy of the IB state for the higher IB–CB energy gap are necessary toward the realization of high-efficiency IBSCs.

Next-generation mid-infrared sources

Science.gov (United States)

Jung, D.; Bank, S.; Lee, M. L.; Wasserman, D.

2017-12-01

The mid-infrared (mid-IR) is a wavelength range with a variety of technologically vital applications in molecular sensing, security and defense, energy conservation, and potentially in free-space communication. The recent development and rapid commercialization of new coherent mid-infrared sources have spurred significant interest in the development of mid-infrared optical systems for the above applications. However, optical systems designers still do not have the extensive optical infrastructure available to them that exists at shorter wavelengths (for instance, in the visible and near-IR/telecom wavelengths). Even in the field of optoelectronic sources, which has largely driven the growing interest in the mid-infrared, the inherent limitations of state-of-the-art sources and the gaps in spectral coverage offer opportunities for the development of new classes of lasers, light emitting diodes and emitters for a range of potential applications. In this topical review, we will first present an overview of the current state-of-the-art mid-IR sources, in particular thermal emitters, which have long been utilized, and the relatively new quantum- and interband-cascade lasers, as well as the applications served by these sources. Subsequently, we will discuss potential mid-infrared applications and wavelength ranges which are poorly served by the current stable of mid-IR sources, with an emphasis on understanding the fundamental limitations of the current source technology. The bulk of the manuscript will then explore both past and recent developments in mid-infrared source technology, including narrow bandgap quantum well lasers, type-I and type-II quantum dot materials, type-II superlattices, highly mismatched alloys, lead-salts and transition-metal-doped II-VI materials. We will discuss both the advantages and limitations of each of the above material systems, as well as the potential new applications which they might serve. All in all, this topical review does not aim

Infrared absorption spectroscopy and chemical kinetics of free radicals

International Nuclear Information System (INIS)

Curl, R.F.; Glass, G.P.

1991-01-01

A new channel producing ketenyl radical (HCCO) was discovered in the flash photolysis of ketene at 193 nm. H 2 CCO + hν(193 nm) → H + HCCO by observation near 2020 cm -1 of the infrared fundamental of ketenyl corresponding to the antisymmetric motion of the heavy atoms. This band has been partially rotationally analyzed and the rate constant for the reaction of ketenyl with NO has been determined. The OH stretching fundamental of hydroxymethyl radical (CH 2 OH) has been observed near 3600 cm -1 producing the radical either by the excimer flash photolysis of acetol (CH 3 COCH 2 OH) or by Cl atom abstraction of a methyl hydrogen from methanol. The assignment of the spectrum to CH 2 OH was confirmed by the agreement of the rate constant for the reaction of the species with O 2 with the literature value. The mechanism of the reaction of C 2 H with O 2 has been explored. There appear to be two channels producing CO product: a fast, direct one producing highly vibrationally excited CO up to v = 6 at the same rate C 2 H disappears and a slow, indirect one producing primarily ground state CO on a much longer timescale than the disappearance of C 2 H. The rate constants for the reactions of C 2 H with CH 4 , C 2 H 6 , C 2 H 4 , D 2 , and CO were determined by following the time decay of a C 2 H infrared transient absorption line originating from the ground vibronic state using diode laser spectroscopy creating the C 2 H by excimer laser flash photolysis (ArF, 193 nm) of CF 3 CCH. The branching ratio into OH of the reaction between NH 2 , and NO, which is the channel thought to propagate the radical chain of the Thermal deNOx process, has been measured up to 925 degree C. The OH yield thus obtained appears to be too small to maintain the process. 5 refs., 3 figs

Fourier–transform infrared spectroscopic characterization of natu ...

Indian Academy of Sciences (India)

We present here the characterization of the fulgurites by Fourier transform infrared (FTIR) absorption, X-ray diffraction and X-ray fluorescence methods. The amorphous nature of the substance has been confirmed by Fourier transform infrared spectra of the fulgurites, which exhibit prominent absorption band in the region ...

Optical absorptions in ZnO/a-Si distributed Bragg reflectors

Energy Technology Data Exchange (ETDEWEB)

Chen, Aqing, E-mail: aqchen@hdu.edu.cn; Chen, Zhian [Hangzhou Dianzi University, College of Materials & Environmental Engineering (China); Zhu, Kaigui [Beihang University, Department of physics (China); Ji, Zhenguo [Hangzhou Dianzi University, College of Materials & Environmental Engineering (China)

2017-01-15

The distributed Bragg reflectors (DBRs) consisting of alternating layers of ZnO and heavy doped amorphous silicon (a-Si) have been fabricated by magnetron sputtering. It is novel to find that the optical absorptions exist in the stopband of the DBRs, and that many discrete strong optical absorption peaks exist in the wavelength range of visible to near-infrared. The calculated results by FDTD show that the absorptions in the stopband mainly exist in the first a-Si layer, and that the light absorbed by other a-Si layers inside contributes to the two absorption peaks in near-infrared range. The strong absorptions ranged from visible to infrared open new possibilities to the enhancement of the performance of amorphous silicon solar cells.

A Micromachined Infrared Senor for an Infrared Focal Plane Array

Directory of Open Access Journals (Sweden)

Seong M. Cho

2008-04-01

Full Text Available A micromachined infrared sensor for an infrared focal plane array has been designed and fabricated. Amorphous silicon was used as a sensing material, and silicon nitride was used as a membrane material. To get a good absorption in infrared range, the sensor structure was designed as a l/4 cavity structure. A Ni-Cr film was selected as an electrode material and mixed etching scheme was applied in the patterning process of the Ni-Cr electrode. All the processes were made in 0.5 μm iMEMS fabricated in the Electronics and Telecommunication Research Institute (ETRI. The processed MEMS sensor had a small membrane deflection less than 0.15 μm. This small deflection can be attributed to the rigorous balancing of the stresses of individual layers. The efficiency of infrared absorption was more than 75% in the wavelength range of 8 ~ 14 μm. The processed infrared sensor showed high responsivity of ~230 kV/W at 1.0V bias and 2 Hz operation condition. The time constant of the sensor was 8.6 msec, which means that the sensor is suitable to be operated in 30 Hz frame rate.

Optoelectronic line transmission an introduction to fibre optics

CERN Document Server

Tricker, Raymond L

2013-01-01

Optoelectronic Line Transmission: An Introduction to Fibre Optics presents a basic introduction as well as a background reference manual on fiber optic transmission. The book discusses the basic principles of optical line transmission; the advantages and disadvantages of optical fibers and optoelectronic signalling; the practical applications of optoelectronics; and the future of optoelectronics. The text also describes the theories of optical line transmission; fibers and cables for optical transmission; transmitters including light-emitting diodes and lasers; and receivers including photodi

Organic Nanofibers from Squarylium Dyes: Local Morphology, Optical, and Electrical Properties

DEFF Research Database (Denmark)

Balzer, Frank; Schiek, Manuela; Osadnik, Andreas

2012-01-01

Environmentally stable, non-toxic squarylium dyes with strong absorption maxima in the red and near infrared spectral region are known for almost fifty years. Despite the fact that their optoelectronic properties distinguish them as promising materials for organics based photovoltaic cells...

Nanocomposites of polypropylene and organophilic clay: X ray diffraction, absorption infrared spectroscopy with fourier transform and water vapor permeation

International Nuclear Information System (INIS)

Morelli, Fernanda C.; Ruvolo Filho, Adhemar

2010-01-01

In this work nano composites were prepared from polypropylene, graft polypropylene with maleic anhydride as compatibilizer and organophilic montmorillonite Cloisite 20A with concentrations of 1.5, 2.5, 5.0 and 7.5% clay. The mixture was made in the melt state using a twin screw extruder. The materials were characterized by X ray diffraction, infrared spectroscopy with Fourier transform and analysis of water vapor permeation. The results of X ray diffraction and absorption infrared spectroscopy indicates the formation of nano composites with structures probably exfoliate and or intercalated for concentrations of 1.5 and 2.5% clay, and provided a marked decrease in the water permeability, corroborating with other analyses. (author)

Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution

Energy Technology Data Exchange (ETDEWEB)

Laroche, G. [Laboratoire d' Ingenierie de Surface, Centre de Recherche sur les Materiaux Avances, Departement de genie des mines, de la metallurgie et des materiaux, Universite Laval, 1065, avenue de la Medecine, Quebec G1V 0A6 (Canada); Centre de recherche du CHUQ, Hopital St Francois d' Assise, 10, rue de l' Espinay, local E0-165, Quebec G1L 3L5 (Canada); Vallade, J. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Agence de l' environnement et de la Ma Latin-Small-Letter-Dotless-I -carettrise de l' Energie, 20, avenue du Gresille, BP 90406, F-49004 Angers Cedex 01 (France); Bazinette, R.; Hernandez, E.; Hernandez, G.; Massines, F. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Nijnatten, P. van [OMT Solutions bv, High Tech Campus 9, 5656AE Eindhoven (Netherlands)

2012-10-15

This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm Multiplication-Sign 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45 Degree-Sign beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

Metamaterial mirrors in optoelectronic devices

KAUST Repository

Esfandyarpour, Majid; Garnett, Erik C.; Cui, Yi; McGehee, Michael D.; Brongersma, Mark L.

2014-01-01

The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

Metamaterial mirrors in optoelectronic devices

KAUST Repository

Esfandyarpour, Majid

2014-06-22

The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

Stack emission monitoring using non-dispersive infrared spectroscopy with an optimized nonlinear absorption cross interference correction algorithm

Directory of Open Access Journals (Sweden)

Y. W. Sun

2013-08-01

Full Text Available In this paper, we present an optimized analysis algorithm for non-dispersive infrared (NDIR to in situ monitor stack emissions. The proposed algorithm simultaneously compensates for nonlinear absorption and cross interference among different gases. We present a mathematical derivation for the measurement error caused by variations in interference coefficients when nonlinear absorption occurs. The proposed algorithm is derived from a classical one and uses interference functions to quantify cross interference. The interference functions vary proportionally with the nonlinear absorption. Thus, interference coefficients among different gases can be modeled by the interference functions whether gases are characterized by linear or nonlinear absorption. In this study, the simultaneous analysis of two components (CO2 and CO serves as an example for the validation of the proposed algorithm. The interference functions in this case can be obtained by least-squares fitting with third-order polynomials. Experiments show that the results of cross interference correction are improved significantly by utilizing the fitted interference functions when nonlinear absorptions occur. The dynamic measurement ranges of CO2 and CO are improved by about a factor of 1.8 and 3.5, respectively. A commercial analyzer with high accuracy was used to validate the CO and CO2 measurements derived from the NDIR analyzer prototype in which the new algorithm was embedded. The comparison of the two analyzers show that the prototype works well both within the linear and nonlinear ranges.

Deposition of Methylammonium Lead Triiodide by Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation

Science.gov (United States)

Barraza, E. Tomas; Dunlap-Shohl, Wiley A.; Mitzi, David B.; Stiff-Roberts, Adrienne D.

2018-02-01

Resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) was used to deposit the metal-halide perovskite (MHP) CH3NH3PbI3 (methylammonium lead triiodide, or MAPbI), creating phase-pure films. Given the moisture sensitivity of these crystalline, multi-component organic-inorganic hybrid materials, deposition of MAPbI by RIR-MAPLE required a departure from the use of water-based emulsions as deposition targets. Different chemistries were explored to create targets that properly dissolved MAPbI components, were stable under vacuum conditions, and enabled resonant laser energy absorption. Secondary phases and solvent contamination in the resulting films were studied through Fourier transform infrared (FTIR) absorbance and x-ray diffraction (XRD) measurements, suggesting that lingering excess methylammonium iodide (MAI) and low-vapor pressure solvents can distort the microstructure, creating crystalline and amorphous non-perovskite phases. Thermal annealing of films deposited by RIR-MAPLE allowed for excess solvent to be evaporated from films without degrading the MAPbI structure. Further, it was demonstrated that RIR-MAPLE does not require excess MAI to create stoichiometric films with optoelectronic properties, crystal structure, and film morphology comparable to films created using more established spin-coating methods for processing MHPs. This work marks the first time a MAPLE-related technique was used to deposit MHPs.

Harvesting renewable energy from Earth's mid-infrared emissions

KAUST Repository

Byrnes, S. J.; Blanchard, R.; Capasso, F.

2014-01-01

It is possible to harvest energy from Earth's thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations.

Harvesting renewable energy from Earth's mid-infrared emissions.

Science.gov (United States)

Byrnes, Steven J; Blanchard, Romain; Capasso, Federico

2014-03-18

It is possible to harvest energy from Earth's thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations.

Dilute bismides for near and mid-infrared applications

DEFF Research Database (Denmark)

Song, Yuxin; Gu, Yi; Ye, Hong

2013-01-01

Dilute bismides are a group of emerging materials with unique properties. Incorporation of a small amount of Bi in common III–V host materials results in large band-gap reduction and strong spin-orbit splitting, leading to potential applications in near-infrared (NIR) and mid-infrared (MIR......) optoelectronics. Recent progresses on molecular beam epitaxy (MBE) of novel III-Sb-Bi, i.e. GaSbBi and InSbBi thin films from our group are summarised in this paper. Quantum well structures based on GaSbBi and InGaAsBi aiming for the optical communication window were grown and characterized....

Harvesting renewable energy from Earth's mid-infrared emissions

KAUST Repository

Byrnes, S. J.

2014-03-03

It is possible to harvest energy from Earth\\'s thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations.

Lasers and optoelectronics fundamentals, devices and applications

CERN Document Server

Maini, Anil K

2013-01-01

With emphasis on the physical and engineering principles, this book provides a comprehensive and highly accessible treatment of modern lasers and optoelectronics. Divided into four parts, it explains laser fundamentals, types of lasers, laser electronics & optoelectronics, and laser applications, covering each of the topics in their entirety, from basic fundamentals to advanced concepts. Key features include: exploration of technological and application-related aspects of lasers and optoelectronics, detailing both existing and emerging applications in industry, medical diag

Intersubband absorption in annealed InAs/GaAs quantum dots: a case for polarization-sensitive infrared detection

International Nuclear Information System (INIS)

Chakrabarti, S; Bhattacharya, P; Stiff-Roberts, A D; Lin, Y Y; Singh, J; Lei, Y; Browning, N

2003-01-01

We have studied the characteristics of intersubband absorption of polarized infrared (IR) radiation in as-grown and annealed self-organized InAs/GaAs quantum dots. It is observed that with the increase of annealing time and temperature, the dots tend to flatten and behave more like quantum wells. As a result, their sensitivity to TE (in-plane)-polarized light decreases and that to TM (out-of-plane)-polarized light increases. The effect could be utilized for the realization of polarization-sensitive IR detectors

All-optical reservoir computer based on saturation of absorption.

Science.gov (United States)

Dejonckheere, Antoine; Duport, François; Smerieri, Anteo; Fang, Li; Oudar, Jean-Louis; Haelterman, Marc; Massar, Serge

2014-05-05

Reservoir computing is a new bio-inspired computation paradigm. It exploits a dynamical system driven by a time-dependent input to carry out computation. For efficient information processing, only a few parameters of the reservoir needs to be tuned, which makes it a promising framework for hardware implementation. Recently, electronic, opto-electronic and all-optical experimental reservoir computers were reported. In those implementations, the nonlinear response of the reservoir is provided by active devices such as optoelectronic modulators or optical amplifiers. By contrast, we propose here the first reservoir computer based on a fully passive nonlinearity, namely the saturable absorption of a semiconductor mirror. Our experimental setup constitutes an important step towards the development of ultrafast low-consumption analog computers.

Exciton confinement in organic dendrimer quantum wells for opto-electronic applications

Science.gov (United States)

Lupton, J. M.; Samuel, I. D. W.; Burn, P. L.; Mukamel, S.

2002-01-01

Organic dendrimers are a fascinating new class of materials for opto-electronic applications. We present coupled electronic oscillator calculations on novel nanoscale conjugated dendrimers for use in organic light-emitting diodes. Strong confinement of excitations at the center of the dendrimers is observed, which accounts for the dependence of intermolecular interactions and charge transport on the degree of branching of the dendrimer. The calculated absorption spectra are in excellent agreement with the measured data and show that benzene rings are shared between excitations on the linear segments of the hyperbranched molecules. The coupled electronic oscillator approach is ideally suited to treat large dendritic molecules.

Radiation effects in optoelectronic devices

International Nuclear Information System (INIS)

Barnes, C.E.; Wiczer, J.J.

1984-05-01

Purpose of this report is to provide not only a summary of radiation damage studies at Sandia National Laboratories, but also of those in the literature on the components of optoelectronic systems: light emitting diodes (LEDs), laser diodes, photodetectors, optical fibers, and optical isolators. This review of radiation damage in optoelectronic components is structured according to device type. In each section, a brief discussion of those device properties relevant to radiation effects is given

Mid-infrared upconversion spectroscopy

DEFF Research Database (Denmark)

Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin; Andersen, H. V.

2016-01-01

Mid-infrared (MIR) spectroscopy is emerging as an attractive alternative to near-infrared or visible spectroscopy. MIR spectroscopy offers a unique possibility to probe the fundamental absorption bands of a large number of gases as well as the vibrational spectra of complex molecules. In this paper...

FeNi{sub 3}/indium tin oxide (ITO) composite nanoparticles with excellent microwave absorption performance and low infrared emissivity

Energy Technology Data Exchange (ETDEWEB)

Fu, Li-Shun; Jiang, Jian-Tang [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhen, Liang, E-mail: lzhen@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); MOE Key Laboratory of Micro-systems and Micro-structures Manufacturing, Harbin Institute of Technology, Harbin 150080 (China); Shao, Wen-Zhu [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2013-03-01

Highlights: Black-Right-Pointing-Pointer Electrical conductivity and infrared emissivity can be controlled by ITO content. Black-Right-Pointing-Pointer The infrared emissivity is the lowest when the mole ratio of In:Sn in sol is 9:1. Black-Right-Pointing-Pointer The permittivity in microwave band can be controlled by the electrical conductivity. Black-Right-Pointing-Pointer EMA performance is significantly influenced by the content of ITO phase. Black-Right-Pointing-Pointer FeNi{sub 3}/ITO composite particles are suitable for both infrared and radar camouflage. - Abstract: FeNi{sub 3}/indium tin oxide (ITO) composite nanoparticles were synthesized by a self-catalyzed reduction method and a sol-gel process. The dependence of the content of ITO phase with the mole ratios of In:Sn of different sols was investigated. The relation between the electrical conductivity, infrared emissivity of FeNi{sub 3}/ITO composite nanoparticles and the content of ITO phase was discussed. Electromagnetic wave absorption (EMA) performance of products was evaluated by using transmission line theory. It was found that EMA performance including the intensity and the location of effective band is significantly dependent on the content of ITO phase. The low infrared emissivity and superior EMA performance of FeNi{sub 3}/ITO composite nanoparticles can be both achieved when the mole ratio of In:Sn in sol is 9:1.

Harvesting renewable energy from Earth’s mid-infrared emissions

Science.gov (United States)

Byrnes, Steven J.; Blanchard, Romain; Capasso, Federico

2014-01-01

It is possible to harvest energy from Earth's thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations. PMID:24591604

Ultrafast Graphene Photonics and Optoelectronics

Science.gov (United States)

2017-04-14

AFRL-AFOSR-JP-TR-2017-0032 Ultrafast Graphene Photonics and Optoelectronics Kuang-Hsiung Wu National Chiao Tung University Final Report 04/14/2017...DATES COVERED (From - To) 18 Apr 2013 to 17 Apr 2016 4. TITLE AND SUBTITLE Ultrafast Graphene Photonics and Optoelectronics 5a.  CONTRACT NUMBER 5b...Prescribed by ANSI Std. Z39.18 Final Report for AOARD Grant FA2386-13-1-4022 “Ultrafast Graphene Photonics and Optoelectronics” Date May 23th, 2016

Time resolved spectra in the infrared absorption and emission from shock heated hydrocarbons

Science.gov (United States)

Bauer, S. H.; Borchardt, D. B.

1990-07-01

We have extended the wavelength range of our previously constructed multichannel, fast recording spectrometer to the mid-infrared. With the initial configuration, using a silicon-diode (photovoltaic) array, we recorded light intensities simultaneously at 20 adjacent wavelengths, each with 20 μs time resolution. For studies in the infrared the silicon diodes are replaced by a 20 element PbSe (photoconducting) array of similar dimensions (1×4 mm/element), cooled by a three-stage thermoelectric device. These elements have useful sensitivities over 1.0-6.7 μm. Three interchangeable gratings in a 1/4 m monochromator cover the following spectral ranges: 1.0-2.5 μm (resolution 33.6 cm-1) 2.5-4.5 μm (16.8 cm-1) 4.0-6.5 μm (16.7 cm-1). Incorporated in the new housing there are individually controlled bias-power sources for each detector, two stages of analogue amplification and a 20-line parallel output to the previously constructed digitizer, and record/hold computer. The immediate application of this system is the study of emission and absorption spectra of shock heated hydrocarbons-C2H2, C4H4 and C6H6-which are possible precursors of species that generate infrared emissions in the interstellar medium. It has been recently proposed that these radiations are due to PAH that emit in the infrared upon relaxation from highly excited states. However, it is possible that such emissions could be due to shock-heated low molecular-weight hydrocarbons, which are known to be present in significant abundances, ejected into the interstellar medium during stellar outer atmospheric eruptions. The full Swan band system appeared in time-integrated emission spectra from shock heated C2H2 (1% in Ar; T5eq~=2500K) no soot was generated. At low resolution the profiles on the high frequency side of the black body maximum show no distinctive features. These could be fitted to Planck curves, with temperatures that declined with time from an initial high that was intermediate between T5 (no

Kinetic and diagnostic studies of molecular plasmas using laser absorption techniques

NARCIS (Netherlands)

Welzel, S.; Rousseau, A.; Davies, P.B.; Röpcke, J.

2007-01-01

Within the last decade mid infrared absorption spectroscopy between 3 and 20 µm, known as Infrared Laser Absorption Spectroscopy (IRLAS) and based on tuneable semiconductor lasers, namely lead salt diode lasers, often called tuneable diode lasers (TDL), and quantum cascade lasers (QCL) has

Far-infrared reflection-absorption spectroscopy of amorphous and polycrystalline gallium arsenide films

International Nuclear Information System (INIS)

Gregory, J.R.

1992-01-01

We have reported far-infrared reflection absorption spectra (30-320CM -1 ) at 30 and 310K for nine films of non-stoichiometric GaAs. The FIRRAS measurements were performed using the grazing incidence FIR double-modulation spectroscopy technique first described by DaCosta and Coleman. The films were fabricated by molecular beam deposition on metallized substrates for two As/Ga molecular beam flux ratios. The films were characterized by depth profilometry, IRAS, XRD, and x-ray microprobe analysis. Film thicknesses ranged from 800 to 5800 angstrom and compositions were 45-50% As for a MB flux ratio of 0.29 and 60-70% As for a ratio of 1.12. FIRRAS measurements were made and characterizations performed for as-deposited films and for 5 hour anneals at 473, 573, 673 and 723 degrees C. Vibrational spectra of the crystallized films were interpreted in terms of the exact reflectivity of a thin dielectric film on a conducting substrate, using a classical Lorentzian dielectric function for the response of the film. Resonances appearing in the open-quote forbidden close-quote region between the TO and LO frequencies were modelled with an effective medium approximation and are interpreted as arising from small-scale surface roughness. The behavior of the amorphous film spectra were examined within two models. The effective force constant model describes the variation of the reflection-absorption maxima with measured crystallite size in terms of the effective vibration frequency of 1-D atomic chains having force constants distributed according to the parameters of the crystalline-to-amorphous relaxation length and the crystalline to amorphous force constant ratio. The dielectric function continuum model uses the relaxation of the crystal momentum selection rule to calculate the reflection-absorption spectrum based on a dielectric function in which the oscillator strength is the normalized product of a constant dipole strength and the smoothed vibrational density of states

Tight beta-turns in peptides. DFT-based study of infrared absorption and vibrational circular dichroism for various conformers including solvent effects

Czech Academy of Sciences Publication Activity Database

Kim, J.; Kapitán, Josef; Lakhani, A.; Bouř, Petr; Keiderling, T. A.

2008-01-01

Roč. 119, 1/3 (2008), s. 81-97 ISSN 1432-881X R&D Projects: GA ČR GA203/06/0420 Grant - others:NSF(US) CHE03-16014 Institutional research plan: CEZ:AV0Z40550506 Keywords : peptide beta -turn * density functional theory * infrared absorption * vibrational circular dichroism Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.370, year: 2008

Infrared Absorption in Acetanilide by Solitons

DEFF Research Database (Denmark)

Careri, G.; Buontempo, U.; Carta, F.

1983-01-01

The infrared spectrum of acetanilide shows a new band that is red shifted from the main amide-I maximum by about 15 cm-1, the intensity of which increases at low temperature. It is suggested that this band may arise from the creation of amide-I solitons that are similar (but not identical) to those...

Mid-Infrared Lasers

Data.gov (United States)

National Aeronautics and Space Administration — Mid infrared solid state lasers for Differential Absorption Lidar (DIAL) systems required for understanding atmospheric chemistry are not available. This program...

Optoelectronic properties of a novel fluorene derivative for organic light-emitting diode

Energy Technology Data Exchange (ETDEWEB)

Yu, Junsheng; Lou, Shuangling; Qian, Jincheng; Jiang, Yadong [University of Electronic Science and Technology of China (UESTC), State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu (China); Zhang, Qing [Shanghai Jiaotong University, Department of Polymer Science, School of Chemistry and Chemical Technology, Shanghai (China)

2009-03-15

We report the optoelectronic properties of a novel fluorene derivative of 6,6'-(9H-fluoren-9,9-diyl)bis(2,3-bis (9,9-dihexyl-9H-fluoren-2-yl)quinoxaline) (BFLBBFLYQ) used for organic light-emitting diode. UV-Vis absorption, photoluminescence (PL) and electroluminescence (EL) spectra of BFLBBFLYQ and the blend doped with N,N'-biphenyl-N,N'-bis-(3-methylphenyl)-1,1'-biphenyl-4,4'-di- amine (TPD) in solid state and in solution were investigated. The results showed that BFLBBFLYQ had a PL peak at 451 nm in solid and solution states and an EL peak at 483 nm with a broad emission band, resulting from fluorenone defects. Exciplex emission was observed in BFLBBFLYQ-TPD blend solid state with a green emission peaking at 530 nm. Also the blend in solution showed solvatochromism in polarity solvent upon UV irradiation. A new absorption band appeared at around 470 nm of BFLBBFLYQ-TPD blend in chloroform solution, and disappeared when diluted in absorption spectrum. Meanwhile, a low energy emission band from 530 to 580 nm appeared and increased with material concentration and UV irradiation time. (orig.)

New Opportunities in Mid-Infrared Emission Control

Directory of Open Access Journals (Sweden)

Peter Geiser

2015-09-01

Full Text Available Tunable laser absorption spectroscopy (TLAS has been well accepted as a preferred measurement technique for many industrial applications in recent years, especially for in situ applications. Previously, mainly near-infrared lasers have been used in TLAS sensors. The advent of compact mid-infrared light sources, like quantum cascade lasers and interband cascade lasers, has made it possible to detect gases with better sensitivity by utilizing fundamental absorption bands and to measure species that do not have any absorption lines in the near-infrared spectral region. This technological advancement has allowed developing new sensors for gases, such as nitric oxide and sulfur dioxide, for industrial applications. Detection limits of better than 1 ppm·m for nitric oxide and better than 10 ppm·m for sulfur dioxide are demonstrated in field experiments.

Infrared absorption cross sections for ethane (C2H6) in the 3 μm region

International Nuclear Information System (INIS)

Harrison, Jeremy J.; Allen, Nicholas D.C.; Bernath, Peter F.

2010-01-01

Infrared absorption cross sections for ethane have been measured in the 3 μm spectral region from spectra recorded using a high-resolution FTIR spectrometer (Bruker IFS 125/HR). Results are presented for pure ethane gas from spectra recorded at 0.004 cm -1 resolution and for mixtures with dry synthetic air from spectra obtained at 0.015 cm -1 resolution (calculated as 0.9/MOPD using the Bruker definition of resolution), at a number of temperatures and pressures appropriate for atmospheric conditions. Intensities were calibrated using three ethane spectra (recorded at 278, 293, and 323 K) taken from the Pacific Northwest National Laboratory (PNNL) IR database.

Optoelectronics technologies for Virtual Reality systems

Science.gov (United States)

Piszczek, Marek; Maciejewski, Marcin; Pomianek, Mateusz; Szustakowski, Mieczysław

2017-08-01

Solutions in the field of virtual reality are very strongly associated with optoelectronic technologies. This applies to both process design and operation of VR applications. Technologies such as 360 cameras and 3D scanners significantly improve the design work. What is more, HMD displays with high field of view or optoelectronic Motion Capture systems and 3D cameras guarantee an extraordinary experience in immersive VR applications. This article reviews selected technologies from the perspective of their use in a broadly defined process of creating and implementing solutions for virtual reality. There is also the ability to create, modify and adapt new approaches that show team own work (SteamVR tracker). Most of the introduced examples are effectively used by authors to create different VR applications. The use of optoelectronic technology in virtual reality is presented in terms of design and operation of the system as well as referring to specific applications. Designers and users of VR systems should take a close look on new optoelectronics solutions, as they can significantly contribute to increased work efficiency and offer completely new opportunities for virtual world reception.

Size-tunable band alignment and optoelectronic properties of transition metal dichalcogenide van der Waals heterostructures

Science.gov (United States)

Zhao, Yipeng; Yu, Wangbing; Ouyang, Gang

2018-01-01

2D transition metal dichalcogenide (TMDC)-based heterostructures exhibit several fascinating properties that can address the emerging market of energy conversion and storage devices. Current achievements show that the vertical stacked TMDC heterostructures can form type II band alignment and possess significant optoelectronic properties. However, a detailed analytical understanding of how to quantify the band alignment and band offset as well as the optimized power conversion efficiency (PCE) is still lacking. Herein, we propose an analytical model to exhibit the PCEs of TMDC van der Waals (vdW) heterostructures and explore the intrinsic mechanism of photovoltaic conversion based on the detailed balance principle and atomic-bond-relaxation correlation mechanism. We find that the PCE of monolayer MoS2/WSe2 can be up to 1.70%, and that of the MoS2/WSe2 vdW heterostructures increases with thickness, owing to increasing optical absorption. Moreover, the results are validated by comparing them with the available evidence, providing realistic efficiency targets and design principles. Highlights • Both electronic and optoelectronic models are developed for vertical stacked MoS2/WSe2 heterostructures. • The underlying mechanism on size effect of electronic and optoelectronic properties for vertical stacked MoS2/WSe2 heterostructures is clarified. • The macroscopically measurable quantities and the microscopical bond identities are connected.

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”.

Diagnostic studies of molecular plasmas using mid-infrared semiconductor lasers

NARCIS (Netherlands)

Röpcke, J.; Welzel, S.; Lang, N.; Hempel, F.; Gatilova, L.; Guaitella, O.; Rousseau, A.; Davies, P.B.

2008-01-01

Within the last decade mid-infrared absorption spectroscopy between 3 and 20 µm, known as infrared laser absorption spectroscopy (IRLAS) and based on tuneable semiconductor lasers, namely lead salt diode lasers, often called tuneable diode lasers (TDL), and quantum cascade lasers (QCL) has

Hydrogen-Bonded Organic Semiconductor Micro- And Nanocrystals: From Colloidal Syntheses to (Opto-)Electronic Devices

Science.gov (United States)

2014-01-01

Organic pigments such as indigos, quinacridones, and phthalocyanines are widely produced industrially as colorants for everyday products as various as cosmetics and printing inks. Herein we introduce a general procedure to transform commercially available insoluble microcrystalline pigment powders into colloidal solutions of variously sized and shaped semiconductor micro- and nanocrystals. The synthesis is based on the transformation of the pigments into soluble dyes by introducing transient protecting groups on the secondary amine moieties, followed by controlled deprotection in solution. Three deprotection methods are demonstrated: thermal cleavage, acid-catalyzed deprotection, and amine-induced deprotection. During these processes, ligands are introduced to afford colloidal stability and to provide dedicated surface functionality and for size and shape control. The resulting micro- and nanocrystals exhibit a wide range of optical absorption and photoluminescence over spectral regions from the visible to the near-infrared. Due to excellent colloidal solubility offered by the ligands, the achieved organic nanocrystals are suitable for solution processing of (opto)electronic devices. As examples, phthalocyanine nanowire transistors as well as quinacridone nanocrystal photodetectors, with photoresponsivity values by far outperforming those of vacuum deposited reference samples, are demonstrated. The high responsivity is enabled by photoinduced charge transfer between the nanocrystals and the directly attached electron-accepting vitamin B2 ligands. The semiconducting nanocrystals described here offer a cheap, nontoxic, and environmentally friendly alternative to inorganic nanocrystals as well as a new paradigm for obtaining organic semiconductor materials from commercial colorants. PMID:25253644

The optoelectronic properties of a photosystem I-carbon nanotube hybrid system

International Nuclear Information System (INIS)

Kaniber, Simone M; Holleitner, Alexander W; Simmel, Friedrich C; Carmeli, Itai

2009-01-01

The photoconductance properties of photosystem I (PSI) covalently bound to carbon nanotubes (CNTs) are measured. We demonstrate that the PSI forms active electronic junctions with the CNTs, enabling control of the CNTs' photoconductance by the PSI. In order to electrically contact the photoactive proteins, a cysteine mutant is generated at one end of the PSI by genetic engineering. The CNTs are covalently bound to this reactive group using carbodiimide chemistry. We detect an enhanced photoconductance signal of the hybrid material at photon wavelengths resonant to the absorption maxima of the PSI compared to non-resonant wavelengths. The measurements prove that it is feasible to integrate photosynthetic proteins into optoelectronic circuits at the nanoscale.

The optoelectronic properties of a photosystem I-carbon nanotube hybrid system

Energy Technology Data Exchange (ETDEWEB)

Kaniber, Simone M; Holleitner, Alexander W [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, D-85748 Garching (Germany); Simmel, Friedrich C [LMU Munich, Geschwister-Scholl-Platz 1, D-80539 Muenchen (Germany); Carmeli, Itai, E-mail: holleitner@wsi.tum.d, E-mail: itai@post.tau.ac.i [Chemistry Department and NIBN, Ben Gurion University, 84105 Be' er Sheva (Israel)

2009-08-26

The photoconductance properties of photosystem I (PSI) covalently bound to carbon nanotubes (CNTs) are measured. We demonstrate that the PSI forms active electronic junctions with the CNTs, enabling control of the CNTs' photoconductance by the PSI. In order to electrically contact the photoactive proteins, a cysteine mutant is generated at one end of the PSI by genetic engineering. The CNTs are covalently bound to this reactive group using carbodiimide chemistry. We detect an enhanced photoconductance signal of the hybrid material at photon wavelengths resonant to the absorption maxima of the PSI compared to non-resonant wavelengths. The measurements prove that it is feasible to integrate photosynthetic proteins into optoelectronic circuits at the nanoscale.

The TApIR experiment. IR absorption spectra of liquid hydrogen isotopologues

International Nuclear Information System (INIS)

Groessle, Robin

2015-01-01

The scope of the thesis is the infrared absorption spectroscopy of liquid hydrogen isotopologues with the tritium absorption infrared spectroscopy (TApIR) experiment at the tritium laboratory Karlsruhe (TLK). The calibration process from the sample preparation to the reference measurements are described. A further issue is the classical evaluation of FTIR absorption spectra and the extension using the rolling circle filter (RCF) including the effects on statistical and systematical errors. The impact of thermal and nuclear spin temperature on the IR absorption spectra is discussed. An empirical based modeling for the IR absorption spectra of liquid hydrogen isotopologues is performed.

The infrared use on boron characterization from pegmatites ores

International Nuclear Information System (INIS)

Rocha Oliveiros, M.V.R.P. da; Neves, C.; Marques, J.

1987-01-01

The study of minerals of zoned pegmatites outcroping near of Governador Valadares, Minas Gerais State, using infrared absorption spectrometry and X-ray diffraction, allowed the identification of B proxing for Si in the tetrahedral sites of some minerals, such as muscovite, biotite, feldspars, quartz and garnets. The valence balancing was achieved with one monolayer of water in the structure as revealed by infrared absorption too. Infrared absorption is a very important research tool to disclose the proxing of B for Si in geological systems where this element occurs only at traces levels as we found in samples from the Ferreirinha pegmatite quarry. Only the mineral phases collected close to the quartz core show the absorption bands linked to the stretching of the B-O bond and to the H 2 O monolayer. (author) [pt

Optical absorption measurement system

International Nuclear Information System (INIS)

Draggoo, V.G.; Morton, R.G.; Sawicki, R.H.; Bissinger, H.D.

1989-01-01

This patent describes a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature

Contribution of water dimer absorption to the millimeter and far infrared atmospheric water continuum

Science.gov (United States)

Scribano, Yohann; Leforestier, Claude

2007-06-01

We present a rigorous calculation of the contribution of water dimers to the absorption coefficient α(ν¯,T ) in the millimeter and far infrared domains, over a wide range (276-310K) of temperatures. This calculation relies on the explicit consideration of all possible transitions within the entire rovibrational bound state manifold of the dimer. The water dimer is described by the flexible 12-dimensional potential energy surface previously fitted to far IR transitions [C. Leforestier et al., J. Chem. Phys. 117, 8710 (2002)], and which was recently further validated by the good agreement obtained for the calculated equilibrium constant Kp(T) with experimental data [Y. Scribano et al., J. Phys. Chem. A. 110, 5411 (2006)]. Transition dipole matrix elements were computed between all rovibrational states up to an excitation energy of 750cm-1, and J =K=5 rotational quantum numbers. It was shown by explicit calculations that these matrix elements could be extrapolated to much higher J values (J=30). Transitions to vibrational states located higher in energy were obtained from interpolation of computed matrix elements between a set of initial states spanning the 0-750cm-1 range and all vibrational states up to the dissociation limit (˜1200cm-1). We compare our calculations with available experimental measurements of the water continuum absorption in the considered range. It appears that water dimers account for an important fraction of the observed continuum absorption in the millimeter region (0-10cm-1). As frequency increases, their relative contribution decreases, becoming small (˜3%) at the highest frequency considered ν¯=944cm-1.

Ultra-thin infrared metamaterial detector for multicolor imaging applications.

Science.gov (United States)

Montoya, John A; Tian, Zhao-Bing; Krishna, Sanjay; Padilla, Willie J

2017-09-18

The next generation of infrared imaging systems requires control of fundamental electromagnetic processes - absorption, polarization, spectral bandwidth - at the pixel level to acquire desirable information about the environment with low system latency. Metamaterial absorbers have sparked interest in the infrared imaging community for their ability to enhance absorption of incoming radiation with color, polarization and/or phase information. However, most metamaterial-based sensors fail to focus incoming radiation into the active region of a ultra-thin detecting element, thus achieving poor detection metrics. Here our multifunctional metamaterial absorber is directly integrated with a novel mid-wave infrared (MWIR) and long-wave infrared (LWIR) detector with an ultra-thin (~λ/15) InAs/GaSb Type-II superlattice (T2SL) interband cascade detector. The deep sub-wavelength metamaterial detector architecture proposed and demonstrated here, thus significantly improves the detection quantum efficiency (QE) and absorption of incoming radiation in a regime typically dominated by Fabry-Perot etalons. Our work evinces the ability of multifunctional metamaterials to realize efficient wavelength selective detection across the infrared spectrum for enhanced multispectral infrared imaging applications.

Exploring the origin of high optical absorption in conjugated polymers

KAUST Repository

Vezie, Michelle S.; Few, Sheridan; Meager, Iain; Pieridou, Galatia; Dö rling, Bernhard; Ashraf, Raja Shahid; Goñ i, Alejandro R.; Bronstein, Hugo; McCulloch, Iain; Hayes, Sophia C.; Campoy-Quiles, Mariano; Nelson, Jenny

2016-01-01

The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

Exploring the origin of high optical absorption in conjugated polymers

KAUST Repository

Vezie, Michelle S.

2016-05-16

The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

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.

An introduction to optoelectronic sensors

CERN Document Server

Tajani, Antonella; Cutolo, Antonello

2009-01-01

This invaluable book offers a comprehensive overview of the technologies and applications of optoelectronic sensors. Based on the R&D experience of more than 70 engineers and scientists, highly representative of the Italian academic and industrial community in this area, this book provides a broad and accurate description of the state-of-the-art optoelectronic technologies for sensing. The most innovative approaches, such as the use of photonic crystals, squeezed states of light and microresonators for sensing, are considered. Application areas range from environment to medicine and healthcare

A simple encapsulation method for organic optoelectronic devices

International Nuclear Information System (INIS)

Sun Qian-Qian; An Qiao-Shi; Zhang Fu-Jun

2014-01-01

The performances of organic optoelectronic devices, such as organic light emitting diodes and polymer solar cells, have rapidly improved in the past decade. The stability of an organic optoelectronic device has become a key problem for further development. In this paper, we report one simple encapsulation method for organic optoelectronic devices with a parafilm, based on ternary polymer solar cells (PSCs). The power conversion efficiencies (PCE) of PSCs with and without encapsulation decrease from 2.93% to 2.17% and from 2.87% to 1.16% after 168-hours of degradation under an ambient environment, respectively. The stability of PSCs could be enhanced by encapsulation with a parafilm. The encapsulation method is a competitive choice for organic optoelectronic devices, owing to its low cost and compatibility with flexible devices. (atomic and molecular physics)

Infrared hyperbolic metasurface based on nanostructured van der Waals materials

Science.gov (United States)

Li, Peining; Dolado, Irene; Alfaro-Mozaz, Francisco Javier; Casanova, Fèlix; Hueso, Luis E.; Liu, Song; Edgar, James H.; Nikitin, Alexey Y.; Vélez, Saül; Hillenbrand, Rainer

2018-02-01

Metasurfaces with strongly anisotropic optical properties can support deep subwavelength-scale confined electromagnetic waves (polaritons), which promise opportunities for controlling light in photonic and optoelectronic applications. We developed a mid-infrared hyperbolic metasurface by nanostructuring a thin layer of hexagonal boron nitride that supports deep subwavelength-scale phonon polaritons that propagate with in-plane hyperbolic dispersion. By applying an infrared nanoimaging technique, we visualize the concave (anomalous) wavefronts of a diverging polariton beam, which represent a landmark feature of hyperbolic polaritons. The results illustrate how near-field microscopy can be applied to reveal the exotic wavefronts of polaritons in anisotropic materials and demonstrate that nanostructured van der Waals materials can form a highly variable and compact platform for hyperbolic infrared metasurface devices and circuits.

Infrared-laser spectroscopy using a long-pathlength absorption cell

International Nuclear Information System (INIS)

Kim, K.C.; Briesmeister, R.A.

1983-01-01

The absorption measurements in an ordinary cell may require typically a few torr pressure of sample gas. At these pressures the absorption lines are usually pressure-broadened and, therefore, closely spaced transitions are poorly resolved even at diode-laser resolution. This situation is greatly improved in Doppler-limited spectroscopy at extremely low sample pressures. Two very long-pathlength absorption cells were developed to be used in conjunction with diode lasers. They were designed to operate at controlled temperatures with the optical pathlength variable up to approx. 1.5 km. Not only very low sample pressures are used for studies with such cells but also the spectroscopic sensitivity is enhanced over conventional methods by a factor of 10 3 to 10 4 , improving the analytical capability of measuring particle densities to the order of 1 x 10'' molecules/cm 3 . This paper presents some analytical aspects of the diode laser spectroscopy using the long-pathlength absorption cells in the areas of absorption line widths, pressure broadening coefficients, isotope composition measurements and trace impurity analysis

Atmospheric lifetimes, infrared absorption spectra, radiative forcings and global warming potentials of NF3 and CF3CF2Cl (CFC-115

Directory of Open Access Journals (Sweden)

A. Totterdill

2016-09-01

Full Text Available Fluorinated compounds such as NF3 and C2F5Cl (CFC-115 are characterised by very large global warming potentials (GWPs, which result from extremely long atmospheric lifetimes and strong infrared absorptions in the atmospheric window. In this study we have experimentally determined the infrared absorption cross sections of NF3 and CFC-115, calculated the radiative forcing and efficiency using two radiative transfer models and identified the effect of clouds and stratospheric adjustment. The infrared cross sections are within 10 % of previous measurements for CFC-115 but are found to be somewhat larger than previous estimates for NF3, leading to a radiative efficiency for NF3 that is 25 % larger than that quoted in the Intergovernmental Panel on Climate Change Fifth Assessment Report. A whole atmosphere chemistry–climate model was used to determine the atmospheric lifetimes of NF3 and CFC-115 to be (509 ± 21 years and (492 ± 22 years, respectively. The GWPs for NF3 are estimated to be 15 600, 19 700 and 19 700 over 20, 100 and 500 years, respectively. Similarly, the GWPs for CFC-115 are 6030, 7570 and 7480 over 20, 100 and 500 years, respectively.

Infrared Absorption in Acetanilide by Solitons

OpenAIRE

Careri, G.; Buontempo, U.; Carta, F.; Gratton, E.; Scott, Alwyn C.

1983-01-01

The infrared spectrum of acetanilide shows a new band that is red shifted from the main amide-I maximum by about 15 cm-1, the intensity of which increases at low temperature. It is suggested that this band may arise from the creation of amide-I solitons that are similar (but not identical) to those proposed by Davydov for the alpha helix in proteins.

Multiple infrared bands absorber based on multilayer gratings

Science.gov (United States)

Liu, Xiaoyi; Gao, Jinsong; Yang, Haigui; Wang, Xiaoyi; Guo, Chengli

2018-03-01

The present study offers an Ag/Si multilayer-grating microstructure based on an Si substrate. The microstructure exhibits designable narrowband absorption in multiple infrared wavebands, especially in mid- and long-wave infrared atmospheric windows. We investigate its resonance mode mechanism, and calculate the resonance wavelengths by the Fabry-Perot and metal-insulator-metal theories for comparison with the simulation results. Furthermore, we summarize the controlling rules of the absorption peak wavelength of the microstructure to provide a new method for generating a Si-based device with multiple working bands in infrared.

Optoelectronic and Photovoltaic Properties of the Air-Stable Organohalide Semiconductor (CH 3 NH 3 ) 3 Bi 2 I 9

KAUST Repository

Abulikemu, Mutalifu

2016-07-14

Lead halide perovskite materials have shown excellent optoelectronic as well as photovoltaic properties. However, the presence of lead and the chemical instability relegate lead halide perovskites to research applications only. Here, we investigate an emerging lead-free and air stable compound (CH3NH3)3Bi2I9 as a non-toxic potential alternative to lead halide perovskites. We have synthesized thin films, powders and millimeter-scale single crystals of (CH3NH3)3Bi2I9 and investigated their structural and optoelectronic properties. We demonstrate that the degree of crystallinity strongly affects the optoelectronic properties of the material, resulting in significantly different band gaps in polycrystalline thin films and single crystals. Surface photovoltage spectroscopy reveals outstanding photocharge generation in the visible (<700 nm), while transient absorption spectroscopy and space charge limited current measurements point to a long exciton lifetime and a high carrier mobility, respectively, similar to lead halide perovskites, pointing to the remarkable potential of this semiconductor. Photovoltaic devices fabricated using this material yield low power conversion efficiency (PCE) to date, but the PCE is expected to rise with improvements in thin film processing and device engineering.

Optoelectronic Evaluation and Loss Analysis of PEDOT:PSS/Si Hybrid Heterojunction Solar Cells.

Science.gov (United States)

Yang, Zhenhai; Fang, Zebo; Sheng, Jiang; Ling, Zhaoheng; Liu, Zhaolang; Zhu, Juye; Gao, Pingqi; Ye, Jichun

2017-12-01

The organic/silicon (Si) hybrid heterojunction solar cells (HHSCs) have attracted considerable attention due to their potential advantages in high efficiency and low cost. However, as a newly arisen photovoltaic device, its current efficiency is still much worse than commercially available Si solar cells. Therefore, a comprehensive and systematical optoelectronic evaluation and loss analysis on this HHSC is therefore highly necessary to fully explore its efficiency potential. Here, a thoroughly optoelectronic simulation is provided on a typical planar polymer poly (3,4-ethylenedioxy thiophene):polystyrenesulfonate (PEDOT:PSS)/Si HHSC. The calculated spectra of reflection and external quantum efficiency (EQE) match well with the experimental results in a full-wavelength range. The losses in current density, which are contributed by both optical losses (i.e., reflection, electrode shield, and parasitic absorption) and electrical recombination (i.e., the bulk and surface recombination), are predicted via carefully addressing the electromagnetic and carrier-transport processes. In addition, the effects of Si doping concentrations and rear surface recombination velocities on the device performance are fully investigated. The results drawn in this study are beneficial to the guidance of designing high-performance PEDOT:PSS/Si HHSCs.

Study on the surface hydroxyl group on solid breeding materials by infrared absorption spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Satoru; Taniguchi, Masaki [Tokyo Univ. (Japan). Faculty of Engineering

1996-10-01

Hydroxyl groups on the surface of Li{sub 2}O were studied by using a diffuse reflectance method with Fourier transform infrared absorption spectroscopy at high temperature up to 973K under controlled D{sub 2}O or D{sub 2} partial pressure. It was found that hydroxyl groups could exist on Li{sub 2}O surface up to 973K under Ar atmosphere. Under D{sub 2}O containing atmosphere, only the sharp peak at 2520cm{sup -1} was observed at 973K in the O-D stretching vibration region. Below 973K, multiple peaks due to the surface -OD were observed and they showed different behavior with temperature or atmosphere. Multiple peaks mean that surface is not homogeneous for D{sub 2}O adsorption. Assignment of the observed peaks to the surface bonding structure was also discussed. (author)

Structural phase transition and opto-electronic properties of NaZnAs

Energy Technology Data Exchange (ETDEWEB)

Djied, A.; Seddik, T.; Merabiha, O. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 (Algeria); Murtaza, G. [Materials Modeling Lab, Department of Physics, Islamia College University, Peshawar (Pakistan); Khenata, R. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 (Algeria); Ahmed, R., E-mail: rashidahmed@utm.my [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor (Malaysia); Bin-Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Uğur, Ş. [Department of Physics, Faculty of Sciences, Gazi University, 06500 Teknikokullar, Ankara (Turkey); Bouhemadou, A. [Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, University Setif 1, 19000 Setif (Algeria)

2015-02-15

Highlights: • First competent characterizations of NaZnAs at the level of FP-LAPW+lo. • NaZnAs, a potential alternative candidate to III-V for photovoltaic applications. • NaZnAs, a cheaper and abundantly available direct band gap semiconductor. • Potential material for solar radiation absorber from infrared to ultraviolet. - Abstract: In this study, we predict the structural phase transitions as well as opto-electronic properties of the filled-tetrahedral (Nowotny-Juza) NaZnAs compound. Calculations employ the full potential (FP) linearized augmented plane wave (LAPW) plus local orbitals (lo) scheme. The exchange-correlation potential is treated within the generalized gradient approximation of Perdew-Burke and Ernzerhof (GGA-PBE). In addition, Tran and Blaha (TB) modified Becke-Johnson (mBJ) potential is also used to obtain more accurate optoelectronic properties. Geometry optimization is performed to obtain reliable total energies and other structural parameters for each NaZnAs phase. In our study, the sequence of the structural phase transition on compression is Cu{sub 2}Sb-type → β → α phase. NaZnAs is a direct (Γ-Γ) band gap semiconductor for all the structural phases. However, compared to PBE-GGA, the mBJ approximation reproduces better fundamental band gaps. Moreover, for insight into its potential for photovoltaic applications, different optical parameters are studied.

Structural phase transition and opto-electronic properties of NaZnAs

International Nuclear Information System (INIS)

Djied, A.; Seddik, T.; Merabiha, O.; Murtaza, G.; Khenata, R.; Ahmed, R.; Bin-Omran, S.; Uğur, Ş.; Bouhemadou, A.

2015-01-01

Highlights: • First competent characterizations of NaZnAs at the level of FP-LAPW+lo. • NaZnAs, a potential alternative candidate to III-V for photovoltaic applications. • NaZnAs, a cheaper and abundantly available direct band gap semiconductor. • Potential material for solar radiation absorber from infrared to ultraviolet. - Abstract: In this study, we predict the structural phase transitions as well as opto-electronic properties of the filled-tetrahedral (Nowotny-Juza) NaZnAs compound. Calculations employ the full potential (FP) linearized augmented plane wave (LAPW) plus local orbitals (lo) scheme. The exchange-correlation potential is treated within the generalized gradient approximation of Perdew-Burke and Ernzerhof (GGA-PBE). In addition, Tran and Blaha (TB) modified Becke-Johnson (mBJ) potential is also used to obtain more accurate optoelectronic properties. Geometry optimization is performed to obtain reliable total energies and other structural parameters for each NaZnAs phase. In our study, the sequence of the structural phase transition on compression is Cu 2 Sb-type → β → α phase. NaZnAs is a direct (Γ-Γ) band gap semiconductor for all the structural phases. However, compared to PBE-GGA, the mBJ approximation reproduces better fundamental band gaps. Moreover, for insight into its potential for photovoltaic applications, different optical parameters are studied

Low-Absorption Liquid Crystals for Infrared Beam Steering

Science.gov (United States)

2015-09-30

controlled the curing temperature at 0oC to obtain small domain size and fast response time is expected. Here, a UV light-emitting diode ( LED ) lamp ...absorption; def.=deformation; w =weak absorption; v.=variable intensity) [B. D. Mistry, A Handbook of Spectroscopic Data: Chemistry- UV , IR, PMR, CNMR and...contributed by the core structure and terminal groups. Due to UV instability of double bonds and carbon-carbon triple bonds, conjugated phenyl rings have

Temperature evaluation of UF6 and cluster detection in nozzle expansion using low-resolution infrared absorption spectroscopy

International Nuclear Information System (INIS)

Sbampato, M.E.; Antunes, L.M.D.; Miranda, S.F.; Sena, S.C.; Santos, A.M.

1998-01-01

The continuous supersonic expansion of pure gaseous UF 6 and mixtures of UF 6 with argon and nitrogen through a bidimensional nozzle was studied using low-resolution infrared spectroscopy in the ν 3 absorption band region. The experiments were carried out in order to calculate the molecular temperature of the beam and also to verify cluster formation in the expansion. The molecular beam temperature evaluation was based on the measurements of the low-resolution bandwidth, which were compared to simulated spectra results. The temperatures were also evaluated using the measured pressure at the end of the nozzle by a Pitot tube. In the conditions where no cluster formation was observed the calculated theoretical temperatures using an equilibrium expansion model are in good agreement with the data obtained through the analysis of the experimental spectra and through the Pitot tube pressure measurement. Cluster formation was observed for temperatures below about 120 K. In these conditions the infrared spectra showed shoulders in the region above 630 cm -1 and a shoulder or band between 616 and 600 cm -1 . (orig.)

Introduction to organic electronic and optoelectronic materials and devices

CERN Document Server

Sun, Sam-Shajing

2008-01-01

Introduction to Optoelectronic Materials, N. Peyghambarian and M. Fallahi Introduction to Optoelectronic Device Principles, J. Piprek Basic Electronic Structures and Charge Carrier Generation in Organic Optoelectronic Materials, S.-S. Sun Charge Transport in Conducting Polymers, V.N. Prigodin and A.J. Epstein Major Classes of Organic Small Molecules for Electronic and Optoelectronics, X. Meng, W. Zhu, and H. Tian Major Classes of Conjugated Polymers and Synthetic Strategies, Y. Li and J. Hou Low Energy Gap, Conducting, and Transparent Polymers, A. Kumar, Y. Ner, and G.A. Sotzing Conjugated Polymers, Fullerene C60, and Carbon Nanotubes for Optoelectronic Devices, L. Qu, L. Dai, and S.-S. Sun Introduction of Organic Superconducting Materials, H. Mori Molecular Semiconductors for Organic Field-Effect Transistors, A. Facchetti Polymer Field-Effect Transistors, H.G.O. Sandberg Organic Molecular Light-Emitting Materials and Devices, F. So and J. Shi Polymer Light-Emitting Diodes: Devices and Materials, X. Gong and ...

Atomic-level molybdenum oxide nanorings with full-spectrum absorption and photoresponsive properties.

Science.gov (United States)

Yang, Yong; Yang, Yang; Chen, Shuangming; Lu, Qichen; Song, Li; Wei, Yen; Wang, Xun

2017-11-16

Superthin nanostructures, particularly with atomic-level thicknesses, typically display unique optical properties because of their exceptional light-matter interactions. Here, we report a facile strategy for the synthesis of sulfur-doped molybdenum oxide nanorings with an atomic-level size (thickness of 0.5 nm) and a tunable ring-in-ring architecture. These atomic-level nanorings displayed strong photo-absorption in both the visible and infrared-light ranges and acted as a photothermal agent. Under irradiation with an 808 nm laser with an intensity of 1 W/cm 2 , a composite of the nanorings embedded in polydimethylsiloxane showed an ultrafast photothermal effect, delivering a local temperature of up to 400 °C within 20 s, which to the best of our knowledge is the highest temperature by light irradiation reported to date. Meanwhile, the resulting nanorings were also employed as a photoinitiator to remotely induce a visible-light shape memory response, self-healing, reshaping performance and reversible actuation of dynamic three-dimensional structures. This study demonstrates an advancement towards controlling atomic-level-sized nanostructures and achieving greatly enhanced optical performances for optoelectronics.

Field Measurements of Water Continuum and Water Dimer Absorption by Active Long Path Differential Optical Absorption Spectroscopy (DOAS)

OpenAIRE

Lotter, Andreas

2006-01-01

Water vapor plays an important role in Earth's radiative budget since water molecules strongly absorb the incoming solar shortwave and the outgoing thermal infrared radiation. Superimposed on the water monomer absorption, a water continuum absorption has long been recognized, but its true nature still remains controversial. On the one hand, this absorption is explained by a deformation of the line shape of the water monomer absorption lines as a consequence of a molecular collision. One the o...

Dual-scale topology optoelectronic processor.

Science.gov (United States)

Marsden, G C; Krishnamoorthy, A V; Esener, S C; Lee, S H

1991-12-15

The dual-scale topology optoelectronic processor (D-STOP) is a parallel optoelectronic architecture for matrix algebraic processing. The architecture can be used for matrix-vector multiplication and two types of vector outer product. The computations are performed electronically, which allows multiplication and summation concepts in linear algebra to be generalized to various nonlinear or symbolic operations. This generalization permits the application of D-STOP to many computational problems. The architecture uses a minimum number of optical transmitters, which thereby reduces fabrication requirements while maintaining area-efficient electronics. The necessary optical interconnections are space invariant, minimizing space-bandwidth requirements.

FABRICATION, MORPHOLOGICAL AND OPTOELECTRONIC ...

African Journals Online (AJOL)

2014-12-31

Dec 31, 2014 ... porous silicon has better optoelectronic properties than bulk .... Measurement: The morphological properties of PS layer such as nanocrystalline size, the .... excess carrier removal by internal recombination and diffusion.

Application of Polarization Modulated Infrared Reflection Absorption Spectroscopy for electrocatalytic activity studies of laccase adsorbed on modified gold electrodes

International Nuclear Information System (INIS)

Olejnik, Piotr; Pawłowska, Aleksandra; Pałys, Barbara

2013-01-01

Orientation of the enzyme macromolecule on the electrode surface is crucially important for the efficiency of the electron transport between the active site and electrode surface. The orientation can be controlled by affecting the surface charge and the pH of the buffer solution. In this contribution we study laccase physically adsorbed on gold surface modified by mercapto-ethanol, lipid and variously charged diazonium salts. Polarization Modulated Infrared Reflection Absorption Spectroscopy (PMIRRAS) enables the molecular orientation study of the protein molecule by comparison of the amide I to amide II band intensity ratios assuming that the protein secondary structure does not change. We observe significant differences in the intensity ratios depending on the kind of support and the enzyme deposition. The comparison of infrared spectra and cyclic voltammetry responses of variously prepared laccase layers reveals that the parallel orientation of beta-sheet moieties results in high enzyme activity

Tunable ultranarrow spectrum selective absorption in a graphene monolayer at terahertz frequency

Science.gov (United States)

Wu, Jun

2016-06-01

Complete absorption in a graphene monolayer at terahertz frequency through the critical coupling effect is investigated. It is achieved by sandwiching the graphene monolayer between a dielectric grating and a Bragg grating. The designed graphene absorber exhibits near-unity absorption at resonance but with an ultranarrow spectrum and antenna-like response, which is attributed to the combined effects of guided mode resonance with dielectric grating and the photonic band gap with Bragg grating. In addition to numerical simulation, the electric field distributions are also illustrated to provide a physical understanding of the perfect absorption effect. Furthermore, the absorption performance can be tuned by only changing the Fermi level of graphene, which is beneficial for real application. It is believed that this study may be useful for designing next-generation graphene-based optoelectronic devices.

Structural, optical and morphological properties of post-growth calcined TiO{sub 2} nanopowder for opto-electronic device application: Ex-situ studies

Energy Technology Data Exchange (ETDEWEB)

Sathyaseelan, B., E-mail: bsseelan03@gmail.com [Dept of Physics, University College of Engineering Arni (A Constituent College of Anna University Chennai) Arni 632326, Tamil Nadu (India); Manikandan, E., E-mail: maniphysics@gmail.com [Central Research Laboratory, Sree Balaji Medical College & Hospital, Bharath University, BIHER, Chrompet, Chennai 600044, Tamil Nadu (India); UNESCO UNISA Africa Chair in Nanosciences & Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Lakshmanan, V. [Dept of Physics, A.C.T College of Engineering & Technology, Nelvoy 603107 Kancheepuram (Dt), Tamil Nadu (India); Baskaran, I. [Dept of Physics, Arignar Anna Government Arts College, Cheyyar 604407, Tamil Nadu (India); Sivakumar, K. [Dept of Physics, Anna University, Chennai 600025, Tamil Nadu (India); Ladchumananandasivam, Rasiah [Dept of Textile Engineering & Post Graduate Programme in Mechanical Engineering Centre of Technology, Federal University of Rio Grande do Norte, Natal (Brazil); Kennedy, J. [UNESCO UNISA Africa Chair in Nanosciences & Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); The MacDiarmid Institute for Advanced Materials and Nanotechnology, PO Box 600, Wellington (New Zealand); Maaza, M., E-mail: maaza@tlabs.ac.za [UNESCO UNISA Africa Chair in Nanosciences & Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa)

2016-06-25

Nanocrystalline TiO{sub 2} powders have been selectively prepared by the simple combustion reaction method using urea as a fuel. The crystalline powder was obtained using a silica basin heated directly on a hot plate at 500 °C until self-ignition occurred. After combustion process, the calcined products were obtained by heating the as-prepared powders for 1 h in air atmosphere at various sintering temperatures [500–900 °C]. The obtained nanopowder materials were systematically characterized by X-day diffraction (XRD), micro-Raman, UV–visible absorption (UV–vis), and Fourier transform infrared (FT-IR) spectroscopics. Powder XRD pattern shows the good agreement rutile phase structured TiO{sub 2} and the sharp diffraction peaks indicates good for crystallinity. The size of a symmetry of the nanoparticles have been measured with aid of a scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), and Brunauer, Emmett and Teller (BET) surface studies. The crystallinity of the powders was found to increase with respect to calcination temperatures. The average specific surface area of the particle was probed using gas adsorption–desorption measurements. Raman spectroscopy experiment was performed to ascertain the nature of TiO{sub 2} powder quality. UV–vis absorption spectra results showed the changes in the absorption edges of TiO{sub 2} report to increasing the calcinations temperatures. - Highlights: • TiO{sub 2} Nanocrystalline powders were prepared by simple combustion reaction method. • Calcined TiO{sub 2} nanopowder obtained by heating for 1 hr in air atmosphere at 500–900 °C. • Systematic characterization employed by XRD, micro-Raman, Optical, SEM, HRTEM. • The size symmetry of nanoparticles measured by electron microscopes BET methods. • Calcinations raises the crystallinity size enhanced for future opto-electronic devices.

Apparatus and method for transient thermal infrared spectrometry

Science.gov (United States)

McClelland, John F.; Jones, Roger W.

1991-12-03

A method and apparatus for enabling analysis of a material (16, 42) by applying a cooling medium (20, 54) to cool a thin surface layer portion of the material and to transiently generate a temperature differential between the thin surface layer portion and the lower portion of the material sufficient to alter the thermal infrared emission spectrum of the material from the black-body thermal infrared emission spectrum of the material. The altered thermal infrared emission spectrum of the material is detected by a spectrometer/detector (28, 50) while the altered thermal infrared emission spectrum is sufficiently free of self-absorption by the material of the emitted infrared radiation. The detection is effected prior to the temperature differential propagating into the lower portion of the material to an extent such that the altered thermal infrared emission spectrum is no longer sufficiently free of self-absorption by the material of emitted infrared radiation, so that the detected altered thermal infrared emission spectrum is indicative of the characteristics relating to the molecular composition of the material.

Optoelectronic engineering of colloidal quantum-dot solar cells beyond the efficiency black hole: a modeling approach

Science.gov (United States)

Mahpeykar, Seyed Milad; Wang, Xihua

2017-02-01

Colloidal quantum dot (CQD) solar cells have been under the spotlight in recent years mainly due to their potential for low-cost solution-processed fabrication and efficient light harvesting through multiple exciton generation (MEG) and tunable absorption spectrum via the quantum size effect. Despite the impressive advances achieved in charge carrier mobility of quantum dot solids and the cells' light trapping capabilities, the recent progress in CQD solar cell efficiencies has been slow, leaving them behind other competing solar cell technologies. In this work, using comprehensive optoelectronic modeling and simulation, we demonstrate the presence of a strong efficiency loss mechanism, here called the "efficiency black hole", that can significantly hold back the improvements achieved by any efficiency enhancement strategy. We prove that this efficiency black hole is the result of sole focus on enhancement of either light absorption or charge extraction capabilities of CQD solar cells. This means that for a given thickness of CQD layer, improvements accomplished exclusively in optic or electronic aspect of CQD solar cells do not necessarily translate into tangible enhancement in their efficiency. The results suggest that in order for CQD solar cells to come out of the mentioned black hole, incorporation of an effective light trapping strategy and a high quality CQD film at the same time is an essential necessity. Using the developed optoelectronic model, the requirements for this incorporation approach and the expected efficiencies after its implementation are predicted as a roadmap for CQD solar cell research community.

The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared – Part 3: Quantification of the mid- and near-infrared water vapor continuum in the 2500 to 7800 cm−1 spectral range under atmospheric conditions

Directory of Open Access Journals (Sweden)

A. Reichert

2016-09-01

Full Text Available We present a first quantification of the near-infrared (NIR water vapor continuum absorption from an atmospheric radiative closure experiment carried out at the Zugspitze (47.42° N, 10.98° E; 2964 m a.s.l.. Continuum quantification is achieved via radiative closure using radiometrically calibrated solar Fourier transform infrared (FTIR absorption spectra covering the 2500 to 7800 cm−1 spectral range. The dry atmospheric conditions at the Zugspitze site (IWV 1.4 to 3.3 mm enable continuum quantification even within water vapor absorption bands, while upper limits for continuum absorption can be provided in the centers of window regions. Throughout 75 % of the 2500 to 7800 cm−1 spectral range, the Zugspitze results agree within our estimated uncertainty with the widely used MT_CKD 2.5.2 model (Mlawer et al., 2012. In the wings of water vapor absorption bands, our measurements indicate about 2–5 times stronger continuum absorption than MT_CKD, namely in the 2800 to 3000 cm−1 and 4100 to 4200 cm−1 spectral ranges. The measurements are consistent with the laboratory measurements of Mondelain et al. (2015, which rely on cavity ring-down spectroscopy (CDRS, and the calorimetric–interferometric measurements of Bicknell et al. (2006. Compared to the recent FTIR laboratory studies of Ptashnik et al. (2012, 2013, our measurements are consistent within the estimated errors throughout most of the spectral range. However, in the wings of water vapor absorption bands our measurements indicate typically 2–3 times weaker continuum absorption under atmospheric conditions, namely in the 3200 to 3400, 4050 to 4200, and 6950 to 7050 cm−1 spectral regions.

Perovskite Materials: Solar Cell and Optoelectronic Applications

Energy Technology Data Exchange (ETDEWEB)

Yang, Bin [ORNL; Geohegan, David B [ORNL; Xiao, Kai [ORNL

2017-01-01

Hybrid organometallic trihalide perovskites are promising candidates in the applications for next-generation, high-performance, low-cost optoelectronic devices, including photovoltaics, light emitting diodes, and photodetectors. Particularly, the solar cells based on this type of materials have reached 22% lab scale power conversion efficiency in only about seven years, comparable to the other thin film photovoltaic technologies. Hybrid perovskite materials not only exhibit superior optoelectronic properties, but also show many interesting physical properties such as ion migration and defect physics, which may allow the exploration of more device functionalities. In this article, the fundamental understanding of the interrelationships between crystal structure, electronic structure, and material properties is discussed. Various chemical synthesis and processing methods for superior device performance in solar cells and optoelectronic devices are reviewed.

Mid infrared lasers for remote sensing applications

Energy Technology Data Exchange (ETDEWEB)

Walsh, Brian M., E-mail: brian.m.walsh@nasa.gov [NASA Langley Research Center, Hampton, VA 23681 (United States); Lee, Hyung R. [National Institute of Aerospace, Hampton, VA 23666 (United States); Barnes, Norman P. [Science Systems and Applications, Inc., Hampton, VA 23666 (United States)

2016-01-15

To accurately measure the concentrations of atmospheric gasses, especially the gasses with low concentrations, strong absorption features must be accessed. Each molecular species or constituent has characteristic mid-infrared absorption features by which either column content or range resolved concentrations can be measured. Because of these characteristic absorption features the mid infrared spectral region is known as the fingerprint region. However, as noted by the Decadal Survey, mid-infrared solid-state lasers needed for DIAL systems are not available. The primary reason is associated with short upper laser level lifetimes of mid infrared transitions. Energy gaps between the energy levels that produce mid-infrared laser transitions are small, promoting rapid nonradiative quenching. Nonradiative quenching is a multiphonon process, the more phonons needed, the smaller the effect. More low energy phonons are required to span an energy gap than high energy phonons. Thus, low energy phonon materials have less nonradiative quenching compared to high energy phonon materials. Common laser materials, such as oxides like YAG, are high phonon energy materials, while fluorides, chlorides and bromides are low phonon materials. Work at NASA Langley is focused on a systematic search for novel lanthanide-doped mid-infrared solid-state lasers using both quantum mechanical models (theoretical) and spectroscopy (experimental) techniques. Only the best candidates are chosen for laser studies. The capabilities of modeling materials, experimental challenges, material properties, spectroscopy, and prospects for lanthanide-doped mid-infrared solid-state laser devices will be presented. - Highlights: • We discuss mid infrared lasers and laser materials. • We discuss applications to remote sensing. • We survey the lanthanide ions in low phonon materials for potential. • We present examples of praseodymium mid infrared spectroscopy and laser design.

Infrared spectroscopy and photochemistry of NCCN+ and CNCN+ trapped in solid neon

International Nuclear Information System (INIS)

Jacox, Marilyn E.; Thompson, Warren E.

2007-01-01

When a Ne:NCCN sample is codeposited at 4.3 K with neon atoms that have been excited in a microwave discharge, the infrared and near infrared spectra of the resulting deposit include a prominent peak at 1799.5 cm -1 , previously assigned to ν 3 of NCCN + , and several new absorptions at higher frequencies which are contributed by combination bands of ground-state NCCN + . The exposure of the deposit to near infrared and red light results in the appearance of two new absorptions which are attributed to CNCN + . The reverse isomerization occurs when the sample is exposed to near ultraviolet radiation, but the two new absorptions are regenerated upon subsequent irradiation with near infrared and red light

Low temperature hydrogen plasma-assisted atomic layer deposition of copper studied using in situ infrared reflection absorption spectroscopy

International Nuclear Information System (INIS)

Chaukulkar, Rohan P.; Rai, Vikrant R.; Agarwal, Sumit; Thissen, Nick F. W.

2014-01-01

Atomic layer deposition (ALD) is an ideal technique to deposit ultrathin, conformal, and continuous metal thin films. However, compared to the ALD of binary materials such as metal oxides and metal nitrides, the surface reaction mechanisms during metal ALD are not well understood. In this study, the authors have designed and implemented an in situ reflection-absorption infrared spectroscopy (IRAS) setup to study the surface reactions during the ALD of Cu on Al 2 O 3 using Cu hexafluoroacetylacetonate [Cu(hfac) 2 ] and a remote H 2 plasma. Our infrared data show that complete ligand-exchange reactions occur at a substrate temperature of 80 °C in the absence of surface hydroxyl groups. Based on infrared data and previous studies, the authors propose that Cu(hfac) 2 dissociatively chemisorbs on the Al 2 O 3 surface, where the Al-O-Al bridge acts as the surface reactive site, leading to surface O-Cu-hfac and O-Al-hfac species. Surface saturation during the Cu(hfac) 2 half-cycle occurs through blocking of the available chemisorption sites. In the next half-reaction cycle, H radicals from an H 2 plasma completely remove these surface hfac ligands. Through this study, the authors have demonstrated the capability of in situ IRAS as a tool to study surface reactions during ALD of metals. While transmission and internal reflection infrared spectroscopy are limited to the first few ALD cycles, IRAS can be used to probe all stages of metal ALD starting from initial nucleation to the formation of a continuous film

A (time-dependent) density functional theory study of the optoelectronic properties of bis-triisopropylsilylethynyl-functionalized acenes

International Nuclear Information System (INIS)

Malloci, G.; Cappellini, G.; Mulas, G.; Mattoni, A.

2013-01-01

We report a comparative study of the optoelectronic properties of small acenes (benzene, anthracene, and pentacene) and their bis-triisopropylsilylethynyl (TIPS) functionalized counterparts. We computed the fundamental gap using density functional theory (DFT) in the framework of the ΔSCF scheme, and the optical absorption spectra by means of time-dependent DFT. Upon TIPS functionalization we observed a lowering of the ionization energy and a rise of the electron affinity; we consequently predict a systematic reduction of the fundamental electronic gap which decreases from ∼ 40% for benzene to ∼ 16% for pentacene. This trend is reflected in the computed optical absorption spectra: for all TIPS-molecules the onset of absorption is red-shifted as compared to their plain precursors. In the case of TIPS-pentacene, in particular, the computed spectrum agrees with the available experimental data. - Highlights: • We evaluate the effect of triisopropylsilylethynyl (TIPS)-substitution on acenes. • We compared the fundamental gap and the optical absorption as a function of size. • We found a general gap reduction following TIPS functionalization. • The gap reduction decreases at increasing size, from 40% for n = 1 to 16% for n = 5. • The onset of absorption is red-shifted as compared to TIPS precursors

A (time-dependent) density functional theory study of the optoelectronic properties of bis-triisopropylsilylethynyl-functionalized acenes

Energy Technology Data Exchange (ETDEWEB)

Malloci, G., E-mail: giuliano.malloci@dsf.unica.it [Istituto Officina dei Materiali (CNR-IOM), Unità di Cagliari, Cittadella Universitaria, I-09042 Monserrato (Italy); Cappellini, G. [Istituto Officina dei Materiali (CNR-IOM), Unità di Cagliari, Cittadella Universitaria, I-09042 Monserrato (Italy); Dipartimento di Fisica, Università degli Studi di Cagliari, Cittadella Universitaria, I-09042 Monserrato (Italy); Mulas, G. [INAF-Osservatorio Astronomico di Cagliari, Strada 54, Località Poggio dei Pini, I-09012 Capoterra (Italy); Mattoni, A. [Istituto Officina dei Materiali (CNR-IOM), Unità di Cagliari, Cittadella Universitaria, I-09042 Monserrato (Italy)

2013-09-30

We report a comparative study of the optoelectronic properties of small acenes (benzene, anthracene, and pentacene) and their bis-triisopropylsilylethynyl (TIPS) functionalized counterparts. We computed the fundamental gap using density functional theory (DFT) in the framework of the ΔSCF scheme, and the optical absorption spectra by means of time-dependent DFT. Upon TIPS functionalization we observed a lowering of the ionization energy and a rise of the electron affinity; we consequently predict a systematic reduction of the fundamental electronic gap which decreases from ∼ 40% for benzene to ∼ 16% for pentacene. This trend is reflected in the computed optical absorption spectra: for all TIPS-molecules the onset of absorption is red-shifted as compared to their plain precursors. In the case of TIPS-pentacene, in particular, the computed spectrum agrees with the available experimental data. - Highlights: • We evaluate the effect of triisopropylsilylethynyl (TIPS)-substitution on acenes. • We compared the fundamental gap and the optical absorption as a function of size. • We found a general gap reduction following TIPS functionalization. • The gap reduction decreases at increasing size, from 40% for n = 1 to 16% for n = 5. • The onset of absorption is red-shifted as compared to TIPS precursors.

Heterogeneously integrated silicon photonics for the mid-infrared and spectroscopic sensing.

Science.gov (United States)

Chen, Yu; Lin, Hongtao; Hu, Juejun; Li, Mo

2014-07-22

Besides being the foundational material for microelectronics, crystalline silicon has long been used for the production of infrared lenses and mirrors. More recently, silicon has become the key material to achieve large-scale integration of photonic devices for on-chip optical interconnect and signal processing. For optics, silicon has significant advantages: it offers a very high refractive index and is highly transparent in the spectral range from 1.2 to 8 μm. To fully exploit silicon’s superior performance in a remarkably broad range and to enable new optoelectronic functionalities, here we describe a general method to integrate silicon photonic devices on arbitrary foreign substrates. In particular, we apply the technique to integrate silicon microring resonators on mid-infrared compatible substrates for operation in the mid-infrared. These high-performance mid-infrared optical resonators are utilized to demonstrate, for the first time, on-chip cavity-enhanced mid-infrared spectroscopic analysis of organic chemicals with a limit of detection of less than 0.1 ng.

Optoelectronic lessons as an interdisciplinary lecture

Science.gov (United States)

Wu, Dan; Wu, Maocheng; Gu, Jihua

2017-08-01

It is noticed that more and more students in college are passionately curious about the optoelectronic technology, since optoelectronic technology has advanced extremely quickly during the last five years and its applications could be found in a lot of domains. The students who are interested in this area may have different educational backgrounds and their majors cover science, engineering, literature and social science, etc. Our course "History of the Optoelectronic Technology" is set up as an interdisciplinary lecture of the "liberal education" at our university, and is available for all students with different academic backgrounds from any departments of our university. The main purpose of the course is to show the interesting and colorful historical aspects of the development of this technology, so that the students from different departments could absorb the academic nourishment they wanted. There are little complex derivations of physical formulas through the whole lecture, but there are still some difficulties about the lecture which is discussed in this paper.

Exploring single-layered SnSe honeycomb polymorphs for optoelectronic and photovoltaic applications

Science.gov (United States)

Ul Haq, Bakhtiar; AlFaify, S.; Ahmed, R.; Butt, Faheem K.; Laref, A.; Shkir, Mohd.

2018-02-01

Single-layered tin selenide that shares the same structure with phosphorene and possesses intriguing optoelectronic properties has received great interest as a two-dimensional material beyond graphene and phosphorene. Herein, we explore the optoelectronic response of the newly discovered stable honeycomb derivatives (such as α , β , γ , δ , and ɛ ) of single-layered SnSe in the framework of density functional theory. The α , β , γ , and δ derivatives of a SnSe monolayer have been found to exhibit an indirect band gap, however, the dispersion of their band-gap edges demonstrates multiple direct band gaps at a relatively high energy. The ɛ -SnSe, however, features an intrinsic direct band gap at the high-symmetry Γ point. Their energy band gaps (0.53, 2.32, 1.52, 1.56, and 1.76 eV for α -, β -, γ -, δ -, and ɛ -SnSe, respectively), calculated at the level of the Tran-Blaha modified Becke-Johnson approach, mostly fall right in the visible range of the electromagnetic spectrum and are in good agreement with the available literature. The optical spectra of these two-dimensional (2D) SnSe polymorphs (besides β -SnSe) are highly anisotropic and possess strictly different optical band gaps along independent diagonal components. They show high absorption in the visible and UV ranges. Similarly, the reflectivity, refraction, and optical conductivities inherit strong anisotropy from the dielectric functions as well and are highly visible-UV polarized along the cartesian coordinates, showing them to be suitable for optical filters, polarizers, and shields against UV radiation. Our investigations suggest these single-layered SnSe allotropes as a promising 2D material for next-generation nanoscale optoelectronic and photovoltaic applications beyond graphene and phosphorene.

CuPc/C60 heterojunction thin film optoelectronic devices

International Nuclear Information System (INIS)

Murtaza, Imran; Karimov, Khasan S.; Qazi, Ibrahim

2010-01-01

The optoelectronic properties of heterojunction thin film devices with ITO/CuPc/C 60 /Al structure have been investigated by analyzing their current-voltage characteristics, optical absorption and photocurrent. In this organic photovoltaic device, CuPc acts as an optically active layer, C 60 as an electron-transporting layer and ITO and Al as electrodes. It is observed that, under illumination, excitons are formed, which subsequently drift towards the interface with C 60 , where an internal electric field is present. The excitons that reach the interface are subsequently dissociated into free charge carriers due to the electric field present at the interface. The experimental results show that in this device the total current density is a function of injected carriers at the electrode-organic semiconductor surface, the leakage current through the organic layer and collected photogenerated current that results from the effective dissociation of excitons. (semiconductor devices)

Stereoscopic construction and practice of optoelectronic technology textbook

Science.gov (United States)

Zhou, Zigang; Zhang, Jinlong; Wang, Huili; Yang, Yongjia; Han, Yanling

2017-08-01

It is a professional degree course textbook for the Nation-class Specialty—Optoelectronic Information Science and Engineering, and it is also an engineering practice textbook for the cultivation of photoelectric excellent engineers. The book seeks to comprehensively introduce the theoretical and applied basis of optoelectronic technology, and it's closely linked to the current development of optoelectronic industry frontier and made up of following core contents, including the laser source, the light's transmission, modulation, detection, imaging and display. At the same time, it also embodies the features of the source of laser, the transmission of the waveguide, the electronic means and the optical processing methods.

High-Performance Near-Infrared Phototransistor Based on n-Type Small-Molecular Organic Semiconductor

KAUST Repository

Li, Feng; Chen, Yin; Ma, Chun; Buttner, Ulrich; Leo, Karl; Wu, Tao

2016-01-01

A solution-processed near-infrared (NIR) organic phototransistor (OPT) based on n-type organic small molecular material BODIPY-BF2 has been successfully fabricated. Its unprecedented performance, as well as its easy fabrication and good stability, mark this BODIPY-BF2 based OPT device as a very promising candidate for optoelectronic applications in the NIR regime.

High-Performance Near-Infrared Phototransistor Based on n-Type Small-Molecular Organic Semiconductor

KAUST Repository

Li, Feng

2016-12-13

A solution-processed near-infrared (NIR) organic phototransistor (OPT) based on n-type organic small molecular material BODIPY-BF2 has been successfully fabricated. Its unprecedented performance, as well as its easy fabrication and good stability, mark this BODIPY-BF2 based OPT device as a very promising candidate for optoelectronic applications in the NIR regime.

Perspectives in optoelectronics

National Research Council Canada - National Science Library

Jha, Sudhanshu S

1995-01-01

..., optoelectronics is playing a major role in both applied as well as basic sciences. In years to come, i t is destined to change the face of information technology and robotics, involving optical sensing and control, information storage, signal and image processing, communications, and computing. Because of the possibility of using large bandwidths availa...

Tuning light emission of PbS nanocrystals from infrared to visible range by cation exchange

KAUST Repository

Binetti, Enrico

2015-10-27

Colloidal semiconductor nanocrystals, with intense and sharp-line emission between red and near-infrared spectral regions, are of great interest for optoelectronic and bio-imaging applications. The growth of an inorganic passivation layer on nanocrystal surfaces is a common strategy to improve their chemical and optical stability and their photoluminescence quantum yield. In particular, cation exchange is a suitable approach for shell growth at the expense of the nanocrystal core size. Here, the cation exchange process is used to promote the formation of a CdS passivation layer on the surface of very small PbS nanocrystals (2.3 nm in diameter), blue shifting their optical spectra and yielding luminescent and stable nanostructures emitting in the range of 700–850 nm. Structural, morphological and compositional investigation confirms the nanocrystal size contraction after the cation-exchange process, while the PbS rock-salt crystalline phase is retained. Absorption and photoluminescence spectroscopy demonstrate the growth of a passivation layer with a decrease of the PbS core size, as inferred by the blue-shift of the excitonic peaks. The surface passivation strongly increases the photoluminescence intensity and the excited state lifetime. In addition, the nanocrystals reveal increased stability against oxidation over time. Thanks to their absorption and emission spectral range and the slow recombination dynamics, such highly luminescent nano-objects can find interesting applications in sensitized photovoltaic cells and light-emitting devices.

Tuning light emission of PbS nanocrystals from infrared to visible range by cation exchange

KAUST Repository

Binetti, Enrico; Striccoli, Marinella; Sibillano, Teresa; Giannini, Cinzia; Brescia, Rosaria; Falqui, Andrea; Comparelli, Roberto; Corricelli, Michela; Tommasi, Raffaele; Agostiano, Angela; Curri, M Lucia

2015-01-01

Colloidal semiconductor nanocrystals, with intense and sharp-line emission between red and near-infrared spectral regions, are of great interest for optoelectronic and bio-imaging applications. The growth of an inorganic passivation layer on nanocrystal surfaces is a common strategy to improve their chemical and optical stability and their photoluminescence quantum yield. In particular, cation exchange is a suitable approach for shell growth at the expense of the nanocrystal core size. Here, the cation exchange process is used to promote the formation of a CdS passivation layer on the surface of very small PbS nanocrystals (2.3 nm in diameter), blue shifting their optical spectra and yielding luminescent and stable nanostructures emitting in the range of 700–850 nm. Structural, morphological and compositional investigation confirms the nanocrystal size contraction after the cation-exchange process, while the PbS rock-salt crystalline phase is retained. Absorption and photoluminescence spectroscopy demonstrate the growth of a passivation layer with a decrease of the PbS core size, as inferred by the blue-shift of the excitonic peaks. The surface passivation strongly increases the photoluminescence intensity and the excited state lifetime. In addition, the nanocrystals reveal increased stability against oxidation over time. Thanks to their absorption and emission spectral range and the slow recombination dynamics, such highly luminescent nano-objects can find interesting applications in sensitized photovoltaic cells and light-emitting devices.

Terahertz optoelectronics in graphene

International Nuclear Information System (INIS)

Otsuji, Taiichi

2016-01-01

Graphene has attracted considerable attention due to its extraordinary carrier transport, optoelectronic, and plasmonic properties originated from its gapless and linear energy spectra enabling various functionalities with extremely high quantum efficiencies that could never be obtained in any existing materials. This paper reviews recent advances in graphene optoelectronics particularly focused on the physics and device functionalities in the terahertz (THz) electromagnetic spectral range. Optical response of graphene is characterized by its optical conductivity and nonequilibrium carrier energy relaxation dynamics, enabling amplification of THz radiation when it is optically or electrically pumped. Current-injection THz lasing has been realized very recently. Graphene plasmon polaritons can greatly enhance the THz light and graphene matter interaction, enabling giant enhancement in detector responsivity as well as amplifier/laser gain. Graphene-based van der Waals heterostructures could give more interesting and energy-efficient functionalities. (author)

Plasmon-enhanced absorption in a metal nanoparticles and photosynthetic molecules hybrid system

Science.gov (United States)

Fan, Zhiyuan; Govorov, Alexander

2010-03-01

Photosystem I from cyanobacteria is one of nature's most efficient light harvesting complexes, converting light energy into electronic energy with a quantum yield of 100% and an energy yield about 58%. It is very attractive to the nanotechnology community because of its nanoscale dimensions and excellent optoelectronic properties. This protein has the potential to be utilized in devices such as solar cells, electric switches, photo-detectors, etc. However, there is one limiting factor for potential applications of a single monolayer of these photosynthetic proteins. One monolayer absorbs less than 1% of sunlight's energy, despite their excellent optoelectronic properties. Recently, experiments [1] have been conducted to enhance light absorption with the assistance of metal nanoparticles as artificial antenna for the photosystem I. Here, we present a theoretical description of the strong plasmon-assisted interactions between the metal nanoparticles and the optical dipoles of the reaction centers observed in the experiments. The resonance and off-resonance plasmon effects enhance the electromagnetic fields around the photosystem-I molecules and, in this way, lead to enhanced absorption. [4pt] [1] I. Carmeli, I. Lieberman, L. Kraversky, Zhiyuan Fan, A. O. Govorov, G. Markovich, and S. Richter, submitted.

Islanding and strain-induced shifts in the infrared absorption peaks of cubic boron nitride thin films

International Nuclear Information System (INIS)

Fahy, S.; Taylor, C.A. II and; Clarke, R.

1997-01-01

Experimental and theoretical investigations of the infrared-active, polarization-dependent phonon frequencies of cubic boron nitride films have been performed in light of recent claims that large frequency shifts during initial nucleation are the result of strain caused by highly nonequilibrium growth conditions. We show that the formation of small, separate grains of cubic boron nitride during the initial growth leads to a frequency shift in the infrared-active transverse-optic mode, polarized normal to the substrate, which is opposite in sign and twice the magnitude of the shift for modes polarized parallel to the substrate. In contrast, film strain causes a frequency shift in the mode polarized normal to the substrate, which is much smaller in magnitude than the frequency shift for modes polarized parallel to the substrate. Normal and off-normal incidence absorption measurements, performed at different stages of nucleation and growth, show that large frequency shifts in the transverse-optic-phonon modes during the initial stage of growth are not compatible with the expected effects of strain, but are in large part due to nucleation of small isolated cubic BN grains which coalesce to form a uniform layer. Numerical results from a simple model of island nucleation and growth are in good agreement with experimental results. copyright 1997 The American Physical Society

Infrared absorption of CH3OSO detected with time-resolved Fourier-transform spectroscopy.

Science.gov (United States)

Chen, Jin-Dah; Lee, Yuan-Pern

2011-03-07

A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to detect temporally resolved infrared absorption spectra of CH(3)OSO produced upon irradiation of a flowing gaseous mixture of CH(3)OS(O)Cl in N(2) or CO(2) at 248 nm. Two intense transient features with origins near 1152 and 994 cm(-1) are assigned to syn-CH(3)OSO; the former is attributed to overlapping bands at 1154 ± 3 and 1151 ± 3 cm(-1), assigned to the S=O stretching mixed with CH(3) rocking (ν(8)) and the S=O stretching mixed with CH(3) wagging (ν(9)) modes, respectively, and the latter to the C-O stretching (ν(10)) mode at 994 ± 6 cm(-1). Two weak bands at 2991 ± 6 and 2956 ± 3 cm(-1) are assigned as the CH(3) antisymmetric stretching (ν(2)) and symmetric stretching (ν(3)) modes, respectively. Observed vibrational transition wavenumbers agree satisfactorily with those predicted with quantum-chemical calculations at level B3P86∕aug-cc-pVTZ. Based on rotational parameters predicted at that level, the simulated rotational contours of these bands agree satisfactorily with experimental results. The simulation indicates that the S=O stretching mode of anti-CH(3)OSO near 1164 cm(-1) likely makes a small contribution to the observed band near 1152 cm(-1). A simple kinetic model of self-reaction is employed to account for the decay of CH(3)OSO and yields a second-order rate coefficient k=(4 ± 2)×10(-10) cm(3)molecule(-1)s(-1). © 2011 American Institute of Physics.

Near-infrared incoherent broadband cavity enhanced absorption spectroscopy (NIR-IBBCEAS) for detection and quantification of natural gas components.

Science.gov (United States)

Prakash, Neeraj; Ramachandran, Arun; Varma, Ravi; Chen, Jun; Mazzoleni, Claudio; Du, Ke

2018-06-28

The principle of near-infrared incoherent broadband cavity enhanced absorption spectroscopy was employed to develop a novel instrument for detecting natural gas leaks as well as for testing the quality of natural gas mixtures. The instrument utilizes the absorption features of methane, butane, ethane, and propane in the wavelength region of 1100 nm to 1250 nm. The absorption cross-section spectrum in this region for methane was adopted from the HITRAN database, and those for the other three gases were measured in the laboratory. A singular-value decomposition (SVD) based analysis scheme was employed for quantifying methane, butane, ethane, and propane by performing a linear least-square fit. The developed instrument achieved a detection limit of 460 ppm, 141 ppm, 175 ppm and 173 ppm for methane, butane, ethane, and propane, respectively, with a measurement time of 1 second and a cavity length of 0.59 m. These detection limits are less than 1% of the Lower Explosive Limit (LEL) for each gas. The sensitivity can be further enhanced by changing the experimental parameters (such as cavity length, lamp power etc.) and using longer averaging intervals. The detection system is a low-cost and portable instrument suitable for performing field monitorings. The results obtained on the gas mixture emphasize the instrument's potential for deployment at industrial facilities dealing with natural gas, where potential leaks pose a threat to public safety.

Two-Photon Absorption in Organometallic Bromide Perovskites

KAUST Repository

Walters, Grant

2015-07-21

Organometallic trihalide perovskites are solution processed semiconductors that have made great strides in third generation thin film light harvesting and light emitting optoelectronic devices. Recently it has been demonstrated that large, high purity single crystals of these perovskites can be synthesized from the solution phase. These crystals’ large dimensions, clean bandgap, and solid-state order, have provided us with a suitable medium to observe and quantify two-photon absorption in perovskites. When CH3NH3PbBr3 single crystals are pumped with intense 800 nm light, we observe band-to-band photoluminescence at 572 nm, indicative of two-photon absorption. We report the nonlinear absorption coefficient of CH3NH3PbBr3 perovskites to be 8.6 cm GW-1 at 800 nm, comparable to epitaxial single crystal semiconductors of similar bandgap. We have leveraged this nonlinear process to electrically autocorrelate a 100 fs pulsed laser using a two-photon perovskite photodetector. This work demonstrates the viability of organometallic trihalide perovskites as a convenient and low-cost nonlinear absorber for applications in ultrafast photonics.

Two-Photon Absorption in Organometallic Bromide Perovskites

KAUST Repository

Walters, Grant; Sutherland, Brandon R; Hoogland, Sjoerd; Shi, Dong; Comin, Riccardo; Sellan, Daniel P.; Bakr, Osman; Sargent, Edward H.

2015-01-01

Organometallic trihalide perovskites are solution processed semiconductors that have made great strides in third generation thin film light harvesting and light emitting optoelectronic devices. Recently it has been demonstrated that large, high purity single crystals of these perovskites can be synthesized from the solution phase. These crystals’ large dimensions, clean bandgap, and solid-state order, have provided us with a suitable medium to observe and quantify two-photon absorption in perovskites. When CH3NH3PbBr3 single crystals are pumped with intense 800 nm light, we observe band-to-band photoluminescence at 572 nm, indicative of two-photon absorption. We report the nonlinear absorption coefficient of CH3NH3PbBr3 perovskites to be 8.6 cm GW-1 at 800 nm, comparable to epitaxial single crystal semiconductors of similar bandgap. We have leveraged this nonlinear process to electrically autocorrelate a 100 fs pulsed laser using a two-photon perovskite photodetector. This work demonstrates the viability of organometallic trihalide perovskites as a convenient and low-cost nonlinear absorber for applications in ultrafast photonics.

A mid-infrared absorption diagnostic for acetylene detection

KAUST Repository

KC, Utsav

2015-05-14

Acetylene is an important combustion intermediate and plays a critical role in soot formation. Accurate measurements of trace concentrations of acetylene can be very useful in validating hydrocarbon oxidation and soot formation mechanisms. Strongest vibrational band of acetylene near 13.7 μm is probed here to develop a highly sensitive absorption diagnostic. Experiments are carried out behind reflected shock waves to measure absorption cross sections of acetylene near 730 cm−1 over a wide range of temperatures (1000–2200 K) and pressures (1–5 bar). The diagnostic is demonstrated by measuring acetylene formation during the shock-heated pyrolysis and oxidation of propene. © 2015 Springer-Verlag Berlin Heidelberg

Optoelectronic properties of four azobenzene-based iminopyridine ligands for photovoltaic application

Directory of Open Access Journals (Sweden)

Aziz El alamy

2017-11-01

Full Text Available Because of organic π-conjugated materials’ optoelectronic properties and potential applications in a wide range of electronic and optoelectronic devices, such as organic solar cells, these materials, including both polymers and oligomers, have been widely studied in recent years. This work reposts a theoretical study using the DFT method on four azobenzene-based iminopyridines. The theoretical ground-state geometry, electronic structure and optoelectronic parameters (highest occupied molecular orbital (HOMO, lowest unoccupied molecular orbital (LUMO energy levels, open-circuit voltage (Voc and oscillator strengths (O.S of the studied molecules were obtained using the density functional theory (DFT and time-dependent (TDDFT approaches. The effects of the structure length and substituents on the geometric and optoelectronic properties of these materials are discussed to investigate the relationship between the molecular structure and the optoelectronic properties. The results of this study are consistent with the experimental ones and suggest that these materials as good candidates for use in photovoltaic devices. Keywords: π-conjugated materials, azobenzene, optoelectronic properties, DFT calculations, HOMO-LUMO gap

Broadband infrared absorption enhancement by electroless-deposited silver nanoparticles

DEFF Research Database (Denmark)

Gritti, Claudia; Raza, Søren; Kadkhodazadeh, Shima

2017-01-01

Decorating semiconductor surfaces with plasmonic nanoparticles (NPs) is considered a viable solution for enhancing the absorptive properties of photovoltaic and photodetecting devices. We propose to deposit silver NPs on top of a semiconductor wafer by a cheap and fast electroless plating technique....... Optical characterization confirms that the random array of electroless-deposited NPs improves absorption by up to 20% in a broadband of nearinfrared frequencies from the bandgap edge to 2000 nm. Due to the small filling fraction of particles, the reflection in the visible range is practically unchanged......, which points to the possible applications of such deposition method for harvesting photons in nanophotonics and photovoltaics. The broadband absorption is a consequence of the resonant behavior of particles with different shapes and sizes, which strongly localize the incident light at the interface...

Rotational structure in molecular infrared spectra

CERN Document Server

di Lauro, Carlo

2013-01-01

Recent advances in infrared molecular spectroscopy have resulted in sophisticated theoretical and laboratory methods that are difficult to grasp without a solid understanding of the basic principles and underlying theory of vibration-rotation absorption spectroscopy. Rotational Structure in Molecular Infrared Spectra fills the gap between these recent, complex topics and the most elementary methods in the field of rotational structure in the infrared spectra of gaseous molecules. There is an increasing need for people with the skills and knowledge to interpret vibration-rotation spectra in many scientific disciplines, including applications in atmospheric and planetary research. Consequently, the basic principles of vibration-rotation absorption spectroscopy are addressed for contemporary applications. In addition to covering operational quantum mechanical methods, spherical tensor algebra, and group theoretical methods applied to molecular symmetry, attention is also given to phase conventions and their effe...

II-VI Narrow-Bandgap Semiconductors for Optoelectronics

Science.gov (United States)

Baker, Ian

The field of narrow-gap II-VI materials is dominated by the compound semiconductor mercury cadmium telluride, (Hg1-x Cd x Te or MCT), which supports a large industry in infrared detectors, cameras and infrared systems. It is probably true to say that HgCdTe is the third most studied semiconductor after silicon and gallium arsenide. Hg1-x Cd x Te is the material most widely used in high-performance infrared detectors at present. By changing the composition x the spectral response of the detector can be made to cover the range from 1 μm to beyond 17 μm. The advantages of this system arise from a number of features, notably: close lattice matching, high optical absorption coefficient, low carrier generation rate, high electron mobility and readily available doping techniques. These advantages mean that very sensitive infrared detectors can be produced at relatively high operating temperatures. Hg1-x Cd x Te multilayers can be readily grown in vapor-phase epitaxial processes. This provides the device engineer with complex doping and composition profiles that can be used to further enhance the electro-optic performance, leading to low-cost, large-area detectors in the future. The main purpose of this chapter is to describe the applications, device physics and technology of II-VI narrow-bandgap devices, focusing on HgCdTe but also including Hg1-x Mn x Te and Hg1-x Zn x Te. It concludes with a review of the research and development programs into third-generation infrared detector technology (so-called GEN III detectors) being performed in centers around the world.

Wavelength standards in the infrared

CERN Document Server

Rao, KN

2012-01-01

Wavelength Standards in the Infrared is a compilation of wavelength standards suitable for use with high-resolution infrared spectrographs, including both emission and absorption standards. The book presents atomic line emission standards of argon, krypton, neon, and xenon. These atomic line emission standards are from the deliberations of Commission 14 of the International Astronomical Union, which is the recognized authority for such standards. The text also explains the techniques employed in determining spectral positions in the infrared. One of the techniques used includes the grating con

Influence of Two Photon Absorption on Soliton Self-Frequency Shift

DEFF Research Database (Denmark)

Steffensen, Henrik; Rottwitt, Karsten; Jepsen, Peter Uhd

2011-01-01

The creation of mid-infrared supercontinua necessitates the use of soft-glass fibers. However, some materials, like chalcogenide, have a substantial two photon absorption. We introduce a model for soliton self-frequency shift that successfully includes this effect.......The creation of mid-infrared supercontinua necessitates the use of soft-glass fibers. However, some materials, like chalcogenide, have a substantial two photon absorption. We introduce a model for soliton self-frequency shift that successfully includes this effect....

Broad-spectrum enhanced absorption of graphene-molybdenum disulfide photovoltaic cells in metal-mirror microcavity

Science.gov (United States)

Jiang-Tao, Liu; Yun-Kai, Cao; Hong, Tong; Dai-Qiang, Wang; Zhen-Hua, Wu

2018-04-01

The optical absorption of graphene-molybdenum disulfide photovoltaic cells (GM-PVc) in wedge-shaped metal-mirror microcavities (w-MMCs) combined with a spectrum-splitting structure was studied. Results showed that the combination of spectrum-splitting structure and w-MMC can enable the light absorption of GM-PVcs to reach about 65% in the broad spectrum. The influence of processing errors on the absorption of GM-PVcs in w-MMCs was 3-14 times lower than that of GM-PVcs in wedge photonic crystal microcavities. The light absorption of GM-PVcs reached 60% in the broad spectrum, even with the processing errors. The proposed structure is easy to implement and may have potentially important applications in the development of ultra-thin and high-efficiency solar cells and optoelectronic devices.

Optoelectronic properties of doped hydrothermal ZnO thin films

KAUST Repository

Mughal, Asad J.

2017-03-10

Group III impurity doped ZnO thin films were deposited on MgAl2O3 substrates using a simple low temperature two-step deposition method involving atomic layer deposition and hydrothermal epitaxy. Films with varying concentrations of either Al, Ga, or In were evaluated for their optoelectronic properties. Inductively coupled plasma atomic emission spectroscopy was used to determine the concentration of dopants within the ZnO films. While Al and Ga-doped films showed linear incorporation rates with the addition of precursors salts in the hydrothermal growth solution, In-doped films were shown to saturate at relatively low concentrations. It was found that Ga-doped films showed the best performance in terms of electrical resistivity and optical absorbance when compared to those doped with In or Al, with a resistivity as low as 1.9 mΩ cm and an optical absorption coefficient of 441 cm−1 at 450 nm.

Advanced educational program in optoelectronics for undergraduates and graduates in electronics

Science.gov (United States)

Vladescu, Marian; Schiopu, Paul

2015-02-01

The optoelectronics education included in electronics curricula at Faculty of Electronics, Telecommunications and Information Technology of "Politehnica" University of Bucharest started in early '90s, and evolved constantly since then, trying to address the growing demand of engineers with a complex optoelectronics profile and to meet the increased requirements of microelectronics, optoelectronics, and lately nanotechnologies. Our goal is to provide a high level of theoretical background combined with advanced experimental tools in laboratories, and also with simulation platforms. That's why we propose an advanced educational program in optoelectronics for both grades of our study program, bachelor and master.

Integrated optoelectronic materials and circuits for optical interconnects

International Nuclear Information System (INIS)

Hutcheson, L.D.

1988-01-01

Conventional interconnect and switching technology is rapidly becoming a critical issue in the realization of systems using high speed silicon and GaAs based technologies. In recent years clock speeds and on-chip density for VLSI/VHSIC technology has made packaging these high speed chips extremely difficult. A strong case can be made for using optical interconnects for on-chip/on-wafer, chip-to-chip and board-to-board high speed communications. GaAs integrated optoelectronic circuits (IOC's) are being developed in a number of laboratories for performing Input/Output functions at all levels. In this paper integrated optoelectronic materials, electronics and optoelectronic devices are presented. IOC's are examined from the standpoint of what it takes to fabricate the devices and what performance can be expected

Nano crystals for Electronic and Optoelectronic Applications

International Nuclear Information System (INIS)

Zhu, T.; Cloutier, S.G.; Ivanov, I; Knappenberger Jr, K.L.; Robel, I.; Zhang, F

2012-01-01

Electronic and optoelectronic devices, from computers and smart cell phones to solar cells, have become a part of our life. Currently, devices with featured circuits of 45 nm in size can be fabricated for commercial use. However, further development based on traditional semiconductor is hindered by the increasing thermal issues and the manufacturing cost. During the last decade, nano crystals have been widely adopted in various electronic and optoelectronic applications. They provide alternative options in terms of ease of processing, low cost, better flexibility, and superior electronic/optoelectronic properties. By taking advantage of solution-processing, self-assembly, and surface engineering, nano crystals could serve as new building blocks for low-cost manufacturing of flexible and large area devices. Tunable electronic structures combined with small exciton binding energy, high luminescence efficiency, and low thermal conductivity make nano crystals extremely attractive for FET, memory device, solar cell, solid-state lighting/display, photodetector, and lasing applications. Efforts to harness the nano crystal quantum tunability have led to the successful demonstration of many prototype devices, raising the public awareness to the wide range of solutions that nano technology can provide for an efficient energy economy. This special issue aims to provide the readers with the latest achievements of nano crystals in electronic and optoelectronic applications, including the synthesis and engineering of nano crystals towards the applications and the corresponding device fabrication, characterization and computer modeling.

Methanogenic activity tests by Infrared Tunable Diode Laser Absorption Spectroscopy.

Science.gov (United States)

Martinez-Cruz, Karla; Sepulveda-Jauregui, Armando; Escobar-Orozco, Nayeli; Thalasso, Frederic

2012-10-01

Methanogenic activity (MA) tests are commonly carried out to estimate the capability of anaerobic biomass to treat effluents, to evaluate anaerobic activity in bioreactors or natural ecosystems, or to quantify inhibitory effects on methanogenic activity. These activity tests are usually based on the measurement of the volume of biogas produced by volumetric, pressure increase or gas chromatography (GC) methods. In this study, we present an alternative method for non-invasive measurement of methane produced during activity tests in closed vials, based on Infrared Tunable Diode Laser Absorption Spectroscopy (MA-TDLAS). This new method was tested during model acetoclastic and hydrogenotrophic methanogenic activity tests and was compared to a more traditional method based on gas chromatography. From the results obtained, the CH(4) detection limit of the method was estimated to 60 ppm and the minimum measurable methane production rate was estimated to 1.09(.)10(-3) mg l(-1) h(-1), which is below CH(4) production rate usually reported in both anaerobic reactors and natural ecosystems. Additionally to sensitivity, the method has several potential interests compared to more traditional methods among which short measurements time allowing the measurement of a large number of MA test vials, non-invasive measurements avoiding leakage or external interferences and similar cost to GC based methods. It is concluded that MA-TDLAS is a promising method that could be of interest not only in the field of anaerobic digestion but also, in the field of environmental ecology where CH(4) production rates are usually very low. Copyright © 2012 Elsevier B.V. All rights reserved.

Short-wave infrared barriode detectors using InGaAsSb absorption material lattice matched to GaSb

Energy Technology Data Exchange (ETDEWEB)

Craig, A. P.; Percy, B.; Marshall, A. R. J. [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Jain, M. [Amethyst Research Ltd., Kelvin Campus, West of Scotland Science Park, Glasgow G20 0SP (United Kingdom); Wicks, G.; Hossain, K. [Amethyst Research, Inc., 123 Case Circle, Ardmore, Oklahoma 73401 (United States); Golding, T. [Amethyst Research Ltd., Kelvin Campus, West of Scotland Science Park, Glasgow G20 0SP (United Kingdom); Amethyst Research, Inc., 123 Case Circle, Ardmore, Oklahoma 73401 (United States); McEwan, K.; Howle, C. [Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ (United Kingdom)

2015-05-18

Short-wave infrared barriode detectors were grown by molecular beam epitaxy. An absorption layer composition of In{sub 0.28}Ga{sub 0.72}As{sub 0.25}Sb{sub 0.75} allowed for lattice matching to GaSb and cut-off wavelengths of 2.9 μm at 250 K and 3.0 μm at room temperature. Arrhenius plots of the dark current density showed diffusion limited dark currents approaching those expected for optimized HgCdTe-based detectors. Specific detectivity figures of around 7×10{sup 10} Jones and 1×10{sup 10} Jones were calculated, for 240 K and room temperature, respectively. Significantly, these devices could support focal plane arrays working at higher operating temperatures.

Total absorption by degenerate critical coupling

Energy Technology Data Exchange (ETDEWEB)

Piper, Jessica R., E-mail: jrylan@stanford.edu; Liu, Victor; Fan, Shanhui, E-mail: shanhui@stanford.edu [Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

2014-06-23

We consider a mirror-symmetric resonator with two ports. We show that, when excited from a single port, complete absorption can be achieved through critical coupling to degenerate resonances with opposite symmetry. Moreover, any time two resonances with opposite symmetry are degenerate in frequency and absorption is always significantly enhanced. In contrast, when two resonances with the same symmetry are nearly degenerate, there is no absorption enhancement. We numerically demonstrate these effects using a graphene monolayer on top of a photonic crystal slab, illuminated from a single side in the near-infrared.

Infrared absorption and Raman scattering spectroscopic studies of condensed ions

International Nuclear Information System (INIS)

Dao, N.Q.; Knidiri, M.

1975-01-01

Infrared and Raman spectra of the complex K 5 (UO 2 ) 2 F 9 were recorded in the region 4000 to 80 cm -1 . Factor group analysis was used to classify the internal vibrations of the binuclear ion (UO 2 ) 2 F 9 5- . Infrared and Raman spectra were assigned and splitting of the internal modes of the (UO 2 ) 2 F 9 5- anion interpreted. (author)

Fluorescent SiC as a New Platform for Visible and Infrared Emitting Applications as Well as Prospective Photovoltaics

DEFF Research Database (Denmark)

Syvaejaervi, Mikael; Sun, Jianwu; Wellmann, Peter

region from 700 to 900 nm with a peak at 830 nm. Further on, the boron is a deep level and replacing the boron with the aluminum, being a shallow acceptor, would open up further emissions in the visible and infrared regions that would allow tuning of emission for selected purposes. The combination......Fluorescent SiC is a novel materials system which may be a new platform for visible and infrared emitting applications. Although SiC is an indirect bandgap semiconductor, the donor acceptor pair emissions involving deep acceptors could become efficient if the acceptor envelope function...... efficient optoelectronic transistions. We have shown that 3C-SiC could be grown in a very high quality. Carrier lifetime is one of the key parameters governing the electronic and optoelectronic devices. Very recently we have synthesized high quality 3C-SiC by a PVT process on 6H-SiC and with a very high...

Optical absorption in planar graphene superlattice: The role of structural parameters

Science.gov (United States)

Azadi, L.; Shojaei, S.

2018-04-01

We theoretically studied the optically driven interband transitions in a planar graphene superlattices (PGSL) formed by patterning graphene sheet on laterally hetrostructured substrate as Sio2/hBN. A tunable optical transitions between minibands is observed based on engineering structural parameters. We derive analytically expression for optical absorption from two-band model. Considerable optical absorption is obtained for different ratios between widths of heterostructured substrate and is explained analytically from the view point of wavefunction engineering and miniband dispersion, in details. The role of different statuses of polarization as circular and linear are considered. Our study paves a way toward the control of optical properties of PGSLs to be implemented in optoelectronics devices.

UV-Vis optoelectronic properties of α-SnWO4: A comparative experimental and density functional theory based study

KAUST Repository

Ziani, Ahmed

2015-09-03

We report a combined experimental and theoretical study on the optoelectronic properties of α-SnWO4 for UV-Vis excitation. The experimentally measured values for thin films were systematically compared with high-accuracy density functional theory and density functional perturbation theory using the HSE06 functional. The α-SnWO4 material shows an indirect bandgap of 1.52 eV with high absorption coefficient in the visible-light range (>2 × 105 cm−1). The results show relatively high dielectric constant (>30) and weak diffusion properties (large effective masses) of excited carriers.

Integrated Optoelectronic Networks for Application-Driven Multicore Computing

Science.gov (United States)

2017-05-08

AFRL-AFOSR-VA-TR-2017-0102 Integrated Optoelectronic Networks for Application- Driven Multicore Computing Sudeep Pasricha COLORADO STATE UNIVERSITY...AND SUBTITLE Integrated Optoelectronic Networks for Application-Driven Multicore Computing 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-13-1-0110 5c...and supportive materials with innovative architectural designs that integrate these components according to system-wide application needs. 15

Analysis of optoelectronic strategic planning in Taiwan by artificial intelligence portfolio tool

Science.gov (United States)

Chang, Rang-Seng

1992-05-01

Taiwan ROC has achieved significant advances in the optoelectronic industry with some Taiwan products ranked high in the world market and technology. Six segmentations of optoelectronic were planned. Each one was divided into several strategic items, design artificial intelligent portfolio tool (AIPT) to analyze the optoelectronic strategic planning in Taiwan. The portfolio is designed to provoke strategic thinking intelligently. This computer- generated strategy should be selected and modified by the individual. Some strategies for the development of the Taiwan optoelectronic industry also are discussed in this paper.

Exploration on the training mode of application-oriented talents majoring in optoelectronic information

Science.gov (United States)

Lv, Hao; Liu, Aimei; Zhang, Shengyi; Xiao, Yongjun

2017-08-01

The optoelectronic information major is a strong theoretical and practical specialty. In view of the problems existing in the application-oriented talents training in the optoelectronic information specialty. Five aspects of the talent cultivation plan, the teaching staff, the teaching content, the practical teaching and the scientific research on the training mode of application-oriented talents majoring in optoelectronic information are putted forward. It is beneficial to the specialty construction of optoelectronic information industry which become close to the development of enterprises, and the depth of the integration of school and enterprise service regional economic optoelectronic information high-end skilled personnel base.

Temperature-dependent optical absorption of SrTiO3

International Nuclear Information System (INIS)

Kok, Dirk J.; Irmscher, Klaus; Naumann, Martin; Guguschev, Christo; Galazka, Zbigniew; Uecker, Reinhard

2015-01-01

The optical absorption edge and near infrared absorption of SrTiO 3 were measured at temperatures from 4 to 1703 K. The absorption edge decreases from 3.25 eV at 4 K to 1.8 eV at 1703 K and is extrapolated to approximately 1.2 eV at the melting point (2350 K). The transmission in the near IR decreases rapidly above 1400 K because of free carrier absorption and is about 50% of the room temperature value at 1673 K. The free carriers are generated by thermal excitation of electrons over the band gap and the formation of charged vacancies. The observed temperature-dependent infrared absorption can be well reproduced by a calculation based on simple models for the intrinsic free carrier concentration and the free carrier absorption coefficient. The measured red shift of the optical absorption edge and the rising free carrier absorption strongly narrow the spectral range of transmission and impede radiative heat transport through the crystal. These effects have to be considered in high temperature applications of SrTiO 3 -based devices, as the number of free carriers rises considerably, and in bulk crystal growth to avoid growth instabilities. Temperature dependent optical absorption edge of SrTiO 3 , measured, fitted, and extrapolated to the melting point. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Secondary treatment of films of colloidal quantum dots for optoelectronics and devices produced thereby

Science.gov (United States)

Semonin, Octavi Escala; Luther, Joseph M; Beard, Matthew C; Chen, Hsiang-Yu

2014-04-01

A method of forming an optoelectronic device. The method includes providing a deposition surface and contacting the deposition surface with a ligand exchange chemical and contacting the deposition surface with a quantum dot (QD) colloid. This initial process is repeated over one or more cycles to form an initial QD film on the deposition surface. The method further includes subsequently contacting the QD film with a secondary treatment chemical and optionally contacting the surface with additional QDs to form an enhanced QD layer exhibiting multiple exciton generation (MEG) upon absorption of high energy photons by the QD active layer. Devices having an enhanced QD active layer as described above are also disclosed.

Qualification of a Multi-Channel Infrared Laser Absorption Spectrometer for Monitoring CO, HCl, HCN, HF, and CO2 Aboard Manned Spacecraft

Science.gov (United States)

Briggs, Ryan M.; Frez, Clifford; Forouhar, Siamak; May, Randy D.; Meyer, Marit E.; Kulis, Michael J.; Berger, Gordon M.

2015-01-01

Monitoring of specific combustion products can provide early-warning detection of accidental fires aboard manned spacecraft and also identify the source and severity of combustion events. Furthermore, quantitative in situ measurements are important for gauging levels of exposure to hazardous gases, particularly on long-duration missions where analysis of returned samples becomes impractical. Absorption spectroscopy using tunable laser sources in the 2 to 5 micrometer wavelength range enables accurate, unambiguous detection of CO, HCl, HCN, HF, and CO2, which are produced in varying amounts through the heating of electrical components and packaging materials commonly used aboard spacecraft. Here, we report on calibration and testing of a five-channel laser absorption spectrometer designed to accurately monitor ambient gas-phase concentrations of these five compounds, with low-level detection limits based on the Spacecraft Maximum Allowable Concentrations. The instrument employs a two-pass absorption cell with a total optical pathlength of 50 cm and a dedicated infrared semiconductor laser source for each target gas. We present results from testing the five-channel sensor in the presence of trace concentrations of the target compounds that were introduced using both gas sources and oxidative pyrolysis (non-flaming combustion) of solid material mixtures.

NEAR-INFRARED SPECTROSCOPY OF POST-AGB STARS

NARCIS (Netherlands)

OUDMAIJER, RD; WATERS, LBFM; VANDERVEEN, WECJ; GEBALLE, TR

The results of a medium resolution near-infrared spectral survey of 18 post-AGB candidate stars are presented. Most of the stars have near-infrared hydrogen lines in absorption, which is normal for their spectral types. Three stars, HD 101584, HD 179821 and HD 170756 have the CO first overtone bands

Critical difference between optoelectronic properties of α- and β-SnWO4semiconductors: A DFT/HSE06 and experimental investigation

KAUST Repository

Harb, Moussab

2016-02-03

The optoelectronic properties of β-SnWO4 are investigated in details using experiments on thin film generated by rapid quenching and the first-principles quantum calculations based on the density functional theory (DFT, including the perturbation approach DFPT) and employing the PBE and the range-separated hybrid exchange-correlation HSE06 functionals. The obtained bandgap, optical absorption coefficient, dielectric constant, and charge-carrier effective masses for β-SnWO4 exhibit data irreconcilable with the reported values: e.g., a large and direct bandgap of 4.30eV (UV-responsive), inconsistent with the values in the literature (visible-responsive). These properties obtained for β-SnWO4 are distinctive from those for α-SnWO4: an indirect bandgap of 1.52eV with higher charge mobilities. These data of intrinsic stoichiometric materials suggest that the literature reported nonstoichiometric materials where defects significantly influence the optoelectronic properties. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Contribution to the study and to the development of continuous infrared absorption analyzers; Contribution a l'etude et a la mise au point des analyseurs en continu par absorption infrarouge

Energy Technology Data Exchange (ETDEWEB)

Coste, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-12-01

The continuous infra-red absorption determination of corrosive gases implies the construction of an original single-beam spectrometer. The use of a vibration-rotation line means that the apparatus function has to undergo an alternating displacement: for one position this function is centered on the line, for other position it is placed close by, but away from any absorption. A non-linear relationship is derived between the concentration of the impurity under consideration, the optical density measured at the centre of the line and the total pressure of the gas mixture. The problem is then solved using an associated specific analog computer. The system is applicable to the determination of low concentrations. The principle proposed in then adapted to an analysis using a non-resolved vibration-rotation band. (authors) [French] Le dosage en continu par absorption infrarouge des gaz corrosifs, implique la construction d'un spectrometre original en simple faisceau. L'utilisation d'une raie de vibration - rotation, conduit a effectuer un deplacement alternatif de la fonction d'appareil: pour une position, celle-ci est centree sur la raie, pour l'autre position elle est placee a proximite mais en dehors de toute absorption. On etablit une relation non lineaire entre la concentration de l'impurete consideree, la densite optique mesuree au centre de la raie et la pression totale du melange gazeux. Le probleme est alors resolu par un calculateur analogique specifique associe. Le systeme s'applique au dosage des faibles concentrations. Le principe propose est ensuite adapte a l'analyse a partir d'une bande de vibration - rotation non resolue. (auteurs)

Broadband infrared absorption enhancement by electroless-deposited silver nanoparticles

DEFF Research Database (Denmark)

Gritti, Claudia; Raza, Søren; Kadkhodazadeh, Shima

2017-01-01

Decorating semiconductor surfaces with plasmonic nanoparticles (NPs) is considered a viable solution for enhancing the absorptive properties of photovoltaic and photodetecting devices. We propose to deposit silver NPs on top of a semiconductor wafer by a cheap and fast electroless plating technique......, which points to the possible applications of such deposition method for harvesting photons in nanophotonics and photovoltaics. The broadband absorption is a consequence of the resonant behavior of particles with different shapes and sizes, which strongly localize the incident light at the interface...

Progress on Crystal Growth of Two-Dimensional Semiconductors for Optoelectronic Applications

Directory of Open Access Journals (Sweden)

Bingqi Sun

2018-06-01

Full Text Available Two-dimensional (2D semiconductors are thought to belong to the most promising candidates for future nanoelectronic applications, due to their unique advantages and capability in continuing the downscaling of complementary metal–oxide–semiconductor (CMOS devices while retaining decent mobility. Recently, optoelectronic devices based on novel synthetic 2D semiconductors have been reported, exhibiting comparable performance to the traditional solid-state devices. This review briefly describes the development of the growth of 2D crystals for applications in optoelectronics, including photodetectors, light-emitting diodes (LEDs, and solar cells. Such atomically thin materials with promising optoelectronic properties are very attractive for future advanced transparent optoelectronics as well as flexible and wearable/portable electronic devices.

Deformable paper origami optoelectronic devices

KAUST Repository

He, Jr-Hau; Lin, Chun-Ho

2017-01-01

Deformable optoelectronic devices are provided, including photodetectors, photodiodes, and photovoltaic cells. The devices can be made on a variety of paper substrates, and can include a plurality of fold segments in the paper substrate creating a

Vibrational excitation of hydrogen molecules by two-photon absorption and third-harmonic generation

Science.gov (United States)

Miyamoto, Yuki; Hara, Hideaki; Hiraki, Takahiro; Masuda, Takahiko; Sasao, Noboru; Uetake, Satoshi; Yoshimi, Akihiro; Yoshimura, Koji; Yoshimura, Motohiko

2018-01-01

We report the coherent excitation of the vibrational state of hydrogen molecules by two-photon absorption and the resultant third-harmonic generation (THG). Parahydrogen molecules cooled by liquid nitrogen are irradiated by mid-infrared nanosecond pulses at 4.8 μm with a nearly Fourier-transform-limited linewidth. The first excited vibrational state of parahydrogen is populated by two-photon absorption of the mid-infrared photons. Because of the narrow linewidth of the mid-infrared pulses, coherence between the ground and excited states is sufficient to induce higher-order processes. Near-infrared photons from the THG are observed at 1.6 μm. The dependence of the intensity of the near-infrared radiation on mid-infrared pulse energy, target pressure, and cell length is determined. We used a simple formula for THG with consideration of realistic experimental conditions to explain the observed results.

Structure Determination of Anionic Metal Clusters via Infrared Resonance Enhanced Multiple Photon Electron Detachment Spectroscopy

NARCIS (Netherlands)

Haertelt, M.; Lapoutre, V. J. F.; Bakker, J. M.; Redlich, B.; Harding, D. J.; Fielicke, A.; Meijer, G.

2011-01-01

We report vibrational spectra of anionic metal clusters, measured via electron detachment following resonant absorption of multiple infrared photons. To facilitate the sequential absorption of the required large number of photons, the cluster beam interacts with the infrared radiation inside the

Infrared absorption spectra of gaseous HD. II. Collision-induced fundamental band of HD in HD--Ne and HD--Ar mixtures at room temperature

International Nuclear Information System (INIS)

Prasad, R.D.G.; Reddy, S.P.

1976-01-01

The collision-induced infrared absorption spectra of the fundamental band of HD in binary mixtures of HD with Ne and Ar at room temperature have been studied with an absorption path length of 105.2 cm for different base densities of HD in the range 8--20 amagat and a number of total gas densities up to 175 amagat. The observed features of the profiles of the enhancement of absorption in these mixtures resemble closely those of the corresponding profiles of the fundamental band of H 2 in binary mixtures with Ne and Ar. The binary absorption coefficients of the band obtained from the measured integrated intensities are (1.84 +- 0.06) x 10 -35 and (4.41 +- 0.06) x 10 -35 cm 6 s -1 for HD--Ne and HD--Ar, respectively. The characteristic half-width parameters, delta/subd/ and delta/subc/ of the overlap transitions and delta/subq/ (and delta/subq//sub prime/) of the quadrupolar transitions, are obtained from an analysis of the profiles of the enhancement of absorption in both these mixtures. The quantity delta/subc/ which is the half-width of the intercollisional interference dip of the Q branch increases with the density of the perturbing gas Ne or Ar, and for HD--Ne it varies in a manner similar to that for HD--He as described in Paper I of this series

Surface-Enhanced Infrared Absorption of o-Nitroaniline on Nickel Nanoparticles Synthesized by Electrochemical Deposition

Directory of Open Access Journals (Sweden)

Yufang Niu

2014-01-01

Full Text Available Nickel nanoparticles were electrochemically deposited on indium-tin oxide (ITO coated glass plate in a modified Watt’s electrolyte. The surface-enhanced infrared absorption (SEIRA effect of the nanoparticles was evaluated by attenuated total reflection spectroscopy (ATR-FTIR using o-nitroaniline as a probe molecule. Electrodeposition parameters such as deposition time, pH value, and the type of surfactants were investigated. The morphology and the microstructure of the deposits were characterized by the field emission scanning electron microscope (FESEM and the atomic force microscope (AFM, respectively. The results indicate that the optimum parameters were potential of 1.3 V, time of 30 s, and pH of 8.92 in the solution of 0.3756 mol/L diethanolamine, 0.1 mol/L nickel sulfate, 0.01 mol/L nickel chloride, and 0.05 mol/L boric acid. The FESEM observation shows that the morphology of nickel nanoparticles with best enhancement effect is spherical and narrowly distributed particles with the average size of 50 nm. SEIRA enhancement factor is about 68.

Absorption in one-dimensional metallic-dielectric photonic crystals

International Nuclear Information System (INIS)

Yu Junfei; Shen Yifeng; Liu Xiaohan; Fu Rongtang; Zi Jian; Zhu Zhiqiang

2004-01-01

We show theoretically that the absorption of one-dimensional metallic-dielectric photonic crystals can be enhanced considerably over the corresponding constituent metal. By properly choosing the structural and material parameters, the absorption of one-dimensional metallic-dielectric photonic crystals can be enhanced by one order of magnitude in the visible and in the near infrared regions. It is found that the absorptance of such photonic crystals increases with increasing number of periods. Rules on how to obtain a absorption enhancement in a certain frequency range are discussed. (letter to the editor)

Apparatus and method for transient thermal infrared spectrometry of flowable enclosed materials

Science.gov (United States)

McClelland, John F.; Jones, Roger W.

1993-03-02

A method and apparatus for enabling analysis of a flowable material enclosed in a transport system having an infrared transparent wall portion. A temperature differential is transiently generated between a thin surface layer portion of the material and a lower or deeper portion of the material sufficient to alter the thermal infrared emission spectrum of the material from the black-body thermal infrared emission spectrum of the material, and the altered thermal infrared emission spectrum is detected through the infrared transparent portion of the transport system while the altered thermal infrared emission spectrum is sufficiently free of self-absorption by the material of emitted infrared radiation. The detection is effected prior to the temperature differential propagating into the lower or deeper portion of the material to an extent such that the altered thermal infrared emission spectrum is no longer sufficiently free of self-absorption by the material of emitted infrared radiation. By such detection, the detected altered thermal infrared emission spectrum is indicative of characteristics relating to molecular composition of the material.

Integrated optoelectronic oscillator.

Science.gov (United States)

Tang, Jian; Hao, Tengfei; Li, Wei; Domenech, David; Baños, Rocio; Muñoz, Pascual; Zhu, Ninghua; Capmany, José; Li, Ming

2018-04-30

With the rapid development of the modern communication systems, radar and wireless services, microwave signal with high-frequency, high-spectral-purity and frequency tunability as well as microwave generator with light weight, compact size, power-efficient and low cost are increasingly demanded. Integrated microwave photonics (IMWP) is regarded as a prospective way to meet these demands by hybridizing the microwave circuits and the photonics circuits on chip. In this article, we propose and experimentally demonstrate an integrated optoelectronic oscillator (IOEO). All of the devices needed in the optoelectronic oscillation loop circuit are monolithically integrated on chip within size of 5×6cm 2 . By tuning the injection current to 44 mA, the output frequency of the proposed IOEO is located at 7.30 GHz with phase noise value of -91 dBc/Hz@1MHz. When the injection current is increased to 65 mA, the output frequency can be changed to 8.87 GHz with phase noise value of -92 dBc/Hz@1MHz. Both of the oscillation frequency can be slightly tuned within 20 MHz around the center oscillation frequency by tuning the injection current. The method about improving the performance of IOEO is carefully discussed at the end of in this article.

Design of Rose Bengal/FTO optical thin film system as a novel nonlinear media for infrared blocking windows

Directory of Open Access Journals (Sweden)

S.M. El-Bashir

Full Text Available Rose Bengal (RB is a new organic semiconductor with the highly stable layer, was deposited on highly cleaned conductive glass substrate known as (FTO glass with different thickness in the range from 80 to 292 nm. XRD showed an entirely amorphous structure of the studied film thicknesses. The observed peaks are the indexed peaks for FTO layer. Spectrophotometric data as transmittance, reflectance, and absorbance were used for the analysis the optical constant of RB/FTO optical thin film system. Refractive index was calculated using Fresnel’s equation with the aid of reflectance and absorption index. The dielectric constant, dielectric loss and dissipation factor were discussed and analyzed according to the applied optical theories. Nonlinear parameters such as third order nonlinear optical susceptibility and the nonlinear refractive index were calculated based on the linear refractive index of the applications of this material in nonlinear media. The results showed that Rose Bengal is a proving material for wide scale optoelectronic applications such as infrared blocking windows. Keywords: Rose Bengal, Dielectric parameters, Linear/nonlinear optics, Dye/FTO, IR blocking windows

Parallel optoelectronic trinary signed-digit division

Science.gov (United States)

Alam, Mohammad S.

1999-03-01

The trinary signed-digit (TSD) number system has been found to be very useful for parallel addition and subtraction of any arbitrary length operands in constant time. Using the TSD addition and multiplication modules as the basic building blocks, we develop an efficient algorithm for performing parallel TSD division in constant time. The proposed division technique uses one TSD subtraction and two TSD multiplication steps. An optoelectronic correlator based architecture is suggested for implementation of the proposed TSD division algorithm, which fully exploits the parallelism and high processing speed of optics. An efficient spatial encoding scheme is used to ensure better utilization of space bandwidth product of the spatial light modulators used in the optoelectronic implementation.

Electronic and optoelectronic device applications based on ReS2

Science.gov (United States)

Liu, Erfu; Long, Mingsheng; Wang, Yaojia; Pan, Yiming; Ho, Chinghwa; Wang, Baigeng; Miao, Feng

Rhenium disulfide (ReS2) is a unique semiconducting TMD with distorted 1T structure and weak interlayer coupling. We have previously investigated its in-plane anisotropic property and electronic applications on FET and digital inverters. In this talk, we will present high responsivity phototransistors based on few-layer ReS2. Depending on the back gate voltage, source drain bias and incident optical light intensity, the maximum attainable photoresponsivity can reach as high as 88,600 A W-1, which is one of the highest value among individual two-dimensional materials with similar device structures. Such high photoresponsivity is attributed to the increased light absorption as well as the gain enhancement due to the existence of trap states in the few-layer ReS2 flakes. The existence of trap states is proved by temperature dependent transport measurements. It further enables the detection of weak signals. Our studies underscore ReS2 as a promising material for future electronic and sensitive optoelectronic applications.

Structure of Co-Doped Alq3 thin films investigated by grazing incidence X-ray absorption fine structure and Fourier transform infrared spectroscopy.

Science.gov (United States)

Lin, Liang; Pang, Zhiyong; Fang, Shaojie; Wang, Fenggong; Song, Shumei; Huang, Yuying; Wei, Xiangjun; Yu, Haisheng; Han, Shenghao

2011-02-10

The structural properties of Co-doped tris(8-hydroxyquinoline)aluminum (Alq(3)) have been studied by grazing incidence X-ray absorption fine structure (GIXAFS) and Fourier transform infrared spectroscopy (FTIR). GIXAFS analysis suggests that there are multivalent Co-Alq(3) complexes and the doped Co atoms tend to locate at the attraction center with respect to N and O atoms and bond with them. The FTIR spectra indicate that the Co atoms interact with the meridional (mer) isomer of Alq(3) rather than forming inorganic compounds.

Fourier transform infrared spectroscopic estimation of crystallinity in ...

Indian Academy of Sciences (India)

Wintec

The crystallinity parameter is calculated by using a standard procedure which can be used to estimate the distribution of quartz in various rocks for mining purpose. The infrared ... The X-ray diffraction full ... crystallinity and trace mineral components of rocks (Partha- ... infrared techniques (Rice et al 1995). ... The absorption.

Broadband and high absorption in Fibonacci photonic crystal including MoS2 monolayer in the visible range

Science.gov (United States)

Ansari, Narges; Mohebbi, Ensiyeh

2018-03-01

2D molybdenum disulfide MoS2, has represented potential applications in optoelectronic devices based on their promising optical absorption responses. However, for practical applications, absorption should increase furthermore in a wide wavelength window. In this paper, we design Fibonacci photonic crystals (PCs) based on Si, SiO2 and MoS2 monolayer and we calculate their absorption responses based on the transfer matrix method. The optical refractive index of the MoS2 monolayer was determined based on the Lorentz-Drude-Gauss model. Effects of Fibonacci order, periodicity, incident light angle and polarization are included in our calculations. Finally, an absorption as large as 90% in a wide optical wavelength range is achieved for both polarizations and incident angle down to 60°. Our results are useful for designing photonic devices with high absorption efficiency.

Study of a thiophene-based polymer for optoelectronic applications

International Nuclear Information System (INIS)

Cheylan, S.; Fraleoni-Morgera, A.; Puigdollers, J.; Voz, C.; Setti, L.; Alcubilla, R.; Badenes, G.; Costa-Bizzarri, P.; Lanzi, M.

2006-01-01

A thiophene-based conjugated polymer bearing a cyano group (-CN) as a side chain substituent was successfully synthesized. The polymer evidences an excellent film ability from various organic solvents as well as an enhanced photoluminescence. The polymer has been characterized optically (Fourier Transformed Infrared spectroscopy, absorption and photoluminescence) in solution and in film, while X-ray diffraction measurements (XRD) of thin films were performed to investigate its bulk morphological features. From the absorption edge of the spectrum of a thin polymer film, the optical band gap of the polymer is estimated to be 2.0 eV, which corresponds to orange emission. Furthermore, a single layer light emitting diode (LED) was fabricated. The device produced bright stable electroluminescence at room temperature. All of the results indicate that this polymer is a promising emissive material for application in polymeric LEDs

Probing photochromic properties by correlation of UV-visible and infra-red absorption spectroscopy: a case study with cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene.

Science.gov (United States)

Spangenberg, Arnaud; Piedras Perez, Jose Alejandro; Patra, Abhijit; Piard, Jonathan; Brosseau, Arnaud; Métivier, Rémi; Nakatani, Keitaro

2010-02-01

Quantification of the relative composition of the isomers in a photochromic system at any irradiation time interval is a critical issue in determining absolute quantum yields. For this purpose, we have developed a simple and convenient protocol involving combination of UV-visible and infra-red absorption spectroscopy. Photochromic cyclization reaction of cis-l,2-dicyano-l,2-bis(2,4,5-trimethyl-3-thieny1)ethene (CMTE) is analyzed to demonstrate the efficiency of the proposed methodology. This approach is based on the fact that the two isomers show distinctive infra-red bands. Detailed investigations of the UV-visible and infra-red spectra of the mixture obtained at different irradiation times in CCl(4) supported by quantum chemical computations lead to the unambiguous estimation of molar absorption coefficients of the closed isomer (epsilon(CF) = 4650 L mol(-1) cm(-1) at 512 nm). It facilitates the first determination of absolute quantum yields of this reversible photochromic reaction in CCl(4) by fitting the UV-visible spectral data (Phi(OF-->CF) = 0.41 +/- 0.05 and Phi(CF-->OF) = 0.12 +/- 0.02 at 405 nm and 546 nm, respectively).

Near-infrared observations of the far-infrared source V region in NGC 6334

International Nuclear Information System (INIS)

Fischer, J.; Joyce, R.R.; Simon, M.; Simon, T.

1982-01-01

We have observed a very red near-infrared source at the center of NGC 6334 FIRS V, a far-infrared source suspected of variability by McBreen et al. The near-infrared source has deep ice and silicate absorption bands, and its half-power size at 20 μm is approx.15'' x 10''. Over the past 2 years we have observed no variability in the near-infrared flux. We have also detected an extended source of H 2 line emission in this region. The total luminosity in the H 2 v-1--0 S(1) line, uncorrected for extinction along the line of sight, is 0.3 L/sub sun/. Detection of emission in high-velocity wings of the J = 1--0 12 CO line suggests that the H 2 emission is associated with a supersonic gas flow

Spectrophotometer-Integrating-Sphere System for Computing Solar Absorptance

Science.gov (United States)

Witte, William G., Jr.; Slemp, Wayne S.; Perry, John E., Jr.

1991-01-01

A commercially available ultraviolet, visible, near-infrared spectrophotometer was modified to utilize an 8-inch-diameter modified Edwards-type integrated sphere. Software was written so that the reflectance spectra could be used to obtain solar absorptance values of 1-inch-diameter specimens. A descriptions of the system, spectral reflectance, and software for calculation of solar absorptance from reflectance data are presented.

Mixed-Alkali Effect in Li2O-Na2O-K2O-B2O3 Glasses: Infrared and Optical Absorption Studies

Science.gov (United States)

Samee, M. A.; Edukondalu, A.; Ahmmad, Shaik Kareem; Taqiullah, Sair Md.; Rahman, Syed

2013-08-01

The mixed-alkali effect (MAE) has been investigated in the glass system (40 - x)Li2O- xNa2O-10K2O-50B2O3 (0 mol% ≤ x ≤ 40 mol%) through density, modulated differential scanning calorimetry (DSC), and optical absorption studies. From the absorption studies, the values of the optical band gap ( E opt) for direct transition and Urbach energy (Δ E) have been evaluated. The values of E opt and Δ E show nonlinear behavior with the compositional parameter. The density and glass-transition temperature of the present glasses also show nonlinear variation, supporting the existence of MAE. The infrared (IR) spectra of the glasses reveal the presence of three- and four-coordinated boron atoms. The specific vibrations of Li-O, Na-O, and K-O bonds were observed in the present IR study.

Design, Synthesis and Optoelectronic Properties of Unsymmetrical Oxadiazole Based Indene Substituted Derivatives as Deep Blue Fluoroscent Materials.

Science.gov (United States)

Belavagi, Ningaraddi S; Deshapande, Narahari; Pujar, G H; Wari, M N; Inamdar, S R; Khazi, Imtiyaz Ahmed M

2015-09-01

A series of novel unsymmetrically substituted indene-oxadiazole derivatives (3a-f) have been designed and synthesized by employing palladium catalysed Suzuki cross coupling reaction in high yields. The structural integrity of all the novel compounds was established by (1)H, (13)C NMR and LC/MS analysis. These compounds are amorphous in nature and are remarkably stable to long term storage under ambient conditions. The optoelectronic properties have been studied in detail using UV-Vis absorption and Fluorescence spectroscopy. All compounds emit intense blue to green-blue fluoroscence with high quantum yields. Time resolved measurments have shown life times in the range of 1.28 to 4.51 ns. The density functional theory (DFT) calculations were carried out for all the molecules to understand their structure-property relationships. Effect of concentration studies has been carried out in different concentrations for both absorption and emission properties and from this we have identified the optimized fluoroscence concentrations for all these compounds. The indene substituted anthracene-oxadiazole derivative (3f) showed significant red shift (λmax (emi) = 490 nm) and emits intense green-blue fluoroscence with largest stokes shift of 145 nm. This compound also exhibited highest fluoroscence life time (τ) of 4.51 ns, which is very close to the standard dye coumarin-540A (4.63 ns) and better than fluorescein-548 (4.10 ns). The results demonstrated that the novel unsymmetrical indene-substituted oxadiazole derivatives could play important role in organic optoelectronic applications, such as organic light-emitting diodes (OLEDs) or as models for investigating the fluorescent structure-property relationship of the indene-functionalized oxadiazole derivatives.

Controlling coulomb interactions in infrared stereometamaterials for unity light absorption

Science.gov (United States)

Mudachathi, Renilkumar; Moritake, Yuto; Tanaka, Takuo

2018-05-01

We investigate the influence of near field interactions between the constituent 3D split ring resonators on the absorbance and resonance frequency of a stereo metamaterial based perfect light absorber. The experimental and theoretical analyses reveal that the magnetic resonance red shifts and broadens for both the decreasing vertical and lateral separations of the constituents within the metamaterial lattice, analogous to plasmon hybridization. The strong interparticle interactions for higher density reduce the effective cross-section per resonator, which results in weak light absorption observed in both experimental and theoretical analyses. The red shift of the magnetic resonance with increasing lattice density is an indication of the dominating electric dipole interactions and we analyzed the metamaterial system in an electrostatic point of view to explain the observed resonance shift and decreasing absorption peak. From these analyses, we found that the fill factor introduces two competing factors determining the absorption efficiency such as coulomb interactions between the constituent resonators and their number density in a given array structure. We predicted unity light absorption for a fill factor of 0.17 balancing these two opposing factors and demonstrate an experimental absorbance of 99.5% at resonance with our 3D device realized using residual stress induced bending of 2D patterns.

Nanocellulose-based Translucent Diffuser for Optoelectronic Device Applications with Dramatic Improvement of Light Coupling.

Science.gov (United States)

Wu, Wei; Tassi, Nancy G; Zhu, Hongli; Fang, Zhiqiang; Hu, Liangbing

2015-12-09

Nanocellulose is a biogenerated and biorenewable organic material. Using a process based on 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)/NaClO/NaBr system, a highly translucent and light-diffusive film consisting of many layers of nanocellulose fibers and wood pulp microfibers was made. The film demonstrates a combination of large optical transmittance of ∼90% and tunable diffuse transmission of up to ∼78% across the visible and near-infrared spectra. The detailed characterizations of the film indicate the combination of high optical transmittance and haze is due to the film's large packing density and microstructured surface. The superior optical properties make the film a translucent light diffuser and applicable for improving the efficiencies of optoelectronic devices such as thin-film silicon solar cells and organic light-emitting devices.

Research on the application of optoelectronics to nuclear power plants

International Nuclear Information System (INIS)

Shirosaki, Hidekazu; Mitsuda, Hiromichi; Kurata, Toshikazu; Soramoto, Seiki; Maekawa, Tatsuyuki.

1995-01-01

Optoelectronics, which is based on technologies such as laser diodes and optical fibers, is approaching the realm of practical application in the fields of optical fiber communications and compact disks etc,. In addition, laser enrichment, a type of uranium enrichment technique used in the nuclear field, can also be regarded as a product of optoelectronics. Application of optoelectronics in a wide range of fields is likely to continue in the future, and research is being conducted on coherent optical communication, optical integrated circuits, optical computers and other subjects in hopes of attaining practical application of these technologies in the future. On the other hand, digital control equipment and other related devices have been installed and data transfer using optical fibers has been implemented on a partial basis at nuclear power plants, and optoelectronics is anticipated to be applied on an even broader scale in the future, thereby creating the potential for improving plant reliability. In this research, we conducted an investigative study of technologies relating to optoelectronics, and proposed a remote monitoring system for manually operated valves that employs optical switches. Moreover, we conducted theoretical verification tests on the proposed system and carried out a feasibility study relating to application to nuclear power plants. As a result, the proposed system was found to be effective, and confirmed to have the potential of realization as a valve switching monitoring system. (author)

Infrared spectroscopy of molecular submonolayers on surfaces by infrared scanning tunneling microscopy: tetramantane on Au111.

Science.gov (United States)

Pechenezhskiy, Ivan V; Hong, Xiaoping; Nguyen, Giang D; Dahl, Jeremy E P; Carlson, Robert M K; Wang, Feng; Crommie, Michael F

2013-09-20

We have developed a new scanning-tunneling-microscopy-based spectroscopy technique to characterize infrared (IR) absorption of submonolayers of molecules on conducting crystals. The technique employs a scanning tunneling microscope as a precise detector to measure the expansion of a molecule-decorated crystal that is irradiated by IR light from a tunable laser source. Using this technique, we obtain the IR absorption spectra of [121]tetramantane and [123]tetramantane on Au(111). Significant differences between the IR spectra for these two isomers show the power of this new technique to differentiate chemical structures even when single-molecule-resolved scanning tunneling microscopy (STM) images look quite similar. Furthermore, the new technique was found to yield significantly better spectral resolution than STM-based inelastic electron tunneling spectroscopy, and to allow determination of optical absorption cross sections. Compared to IR spectroscopy of bulk tetramantane powders, infrared scanning tunneling microscopy (IRSTM) spectra reveal narrower and blueshifted vibrational peaks for an ordered tetramantane adlayer. Differences between bulk and surface tetramantane vibrational spectra are explained via molecule-molecule interactions.

Strain-enhanced optical absorbance of topological insulator films

DEFF Research Database (Denmark)

Brems, Mathias Rosdahl; Paaske, Jens; Lunde, Anders Mathias

2018-01-01

Topological insulator films are promising materials for optoelectronics due to a strong optical absorption and a thickness-dependent band gap of the topological surface states. They are superior candidates for photodetector applications in the THz-infrared spectrum, with a potential performance...... thickness, the surface-state band gap, and thereby the optical absorption, can be effectively tuned by the application of uniaxial strain epsilon(zz), leading to a divergent band-edge absorbance for epsilon(zz) greater than or similar to 6%. Shear strain breaks the crystal symmetry and leads...

Optoelectronic interconnects for 3D wafer stacks

Science.gov (United States)

Ludwig, David; Carson, John C.; Lome, Louis S.

1996-01-01

Wafer and chip stacking are envisioned as means of providing increased processing power within the small confines of a three-dimensional structure. Optoelectronic devices can play an important role in these dense 3-D processing electronic packages in two ways. In pure electronic processing, optoelectronics can provide a method for increasing the number of input/output communication channels within the layers of the 3-D chip stack. Non-free space communication links allow the density of highly parallel input/output ports to increase dramatically over typical edge bus connections. In hybrid processors, where electronics and optics play a role in defining the computational algorithm, free space communication links are typically utilized for, among other reasons, the increased network link complexity which can be achieved. Free space optical interconnections provide bandwidths and interconnection complexity unobtainable in pure electrical interconnections. Stacked 3-D architectures can provide the electronics real estate and structure to deal with the increased bandwidth and global information provided by free space optical communications. This paper will provide definitions and examples of 3-D stacked architectures in optoelectronics processors. The benefits and issues of these technologies will be discussed.

Infrared emission from a polycyclic aromatic hydrocarbon (PAH) excited by ultraviolet laser

International Nuclear Information System (INIS)

Cherchneff, I.; Barker, J.R.

1989-01-01

The infrared fluorescence spectrum from the C-H stretch modes of vibrationally excited azulene (C10H8), a PAH was measured in the laboratory. PAHs are candidates as carriers of the unidentified infrared emission bands that are observed in many astronomical objects associated with dust and ultraviolet light. In the present experiment, gas phase azulene was excited with light from a 308 nm pulsed laser, and the infrared emission spectrum was time-resolved and wavelength-resolved. Moreover, the infrared absorption spectrum of gas phase azulene was obtained using an FTIR spectrometer. The laboratory emission spectrum resembles observed infrared emission spectra from the interstellar medium, providing support for the hypothesis that PAHs are the responsible carriers. The azulene C-H stretch emission spectrum is more asymmetric than the absorption spectrum, probably due to anharmonicity of levels higher than nu = 1. 36 refs

Optoelectronic switch matrix as a look-up table for residue arithmetic.

Science.gov (United States)

Macdonald, R I

1987-10-01

The use of optoelectronic matrix switches to perform look-up table functions in residue arithmetic processors is proposed. In this application, switchable detector arrays give the advantage of a greatly reduced requirement for optical sources by comparison with previous optoelectronic residue processors.

Infrared irradiation of skin for the development of non-invasive health monitoring technologies

Science.gov (United States)

Abdussamad Abbas, Hisham; Triplett, Gregory

2015-06-01

Infrared radiation was employed to study the optical transmission properties of pigskin and the factors that influence transmission at room temperature. The skin samples from the forehead of piglets were irradiated using an infrared-pulsed source by varying the beam properties such as optical power, power density, duty cycle, as well as sample thickness. Because infrared radiation in select instances can penetrate through thick-fleshy skin more easily than visible radiation, temperature fluctuations observed within the skin samples stemming from exposure-dependent absorption revealed interesting transmission properties and the limits of optical exposure. Pigskin was selected for this study since its structure most closely resembles that of human skin. Furthermore, the pulsed beam technique compared to continuous operation offers more precise control of heat generation within the skin. Through this effort, the correlated pulsed-beam parameters that influence infrared transmission were identified and varied to minimize the internal absorption losses through the dermis layers. The two most significant parameters that reduce absorption losses were frequency and duty cycle of the pulsed beam. Using the Bouger-Beer-Lambert Law, the absorption coefficient from empirical data is approximated, while accepting that the absorption coefficient is neither uniform nor linear. Given that the optical source used in this study was single mode, the infrared spectra obtained from irradiated samples also reveal characteristics of the skin structure. Realization of appropriate sample conditions and exposure parameters that reduce light attenuation within the skin and sample degradation could give way to novel non-invasive measuring techniques for health monitoring purposes.

The construction of bilingual teaching of optoelectronic technology

Science.gov (United States)

Zhang, Yang; Zhao, Enming; Yang, Fan; Li, Qingbo; Zhu, Zheng; Li, Cheng; Sun, Peng

2017-08-01

This paper combines the characteristics of optoelectronic technology with that of bilingual teaching. The course pays attention to integrating theory with practice, and cultivating learners' ability. Reform and exploration have been done in the fields of teaching materials, teaching content, teaching methods, etc. The concrete content mainly includes five parts: selecting teaching materials, establishing teaching syllabus, choosing suitable teaching method, making multimedia courseware and improving the test system, which can arouse students' interest in their study and their autonomous learning ability to provide beneficial references for improving the quality of talents of optoelectronic bilingual courses.

Infrared absorption in pseudobinary InSb1-xBix compounds

International Nuclear Information System (INIS)

El-Den, M.B.; Mina, N.K.; Samy, A.M.; El-Mously, M.K.

1988-08-01

The group III-V pseudobinary InSb 1-x Bi x compounds, with x = 0, 0.2 and 0.04, were prepared in thin ribbon forms (30 μ) by splat cooling in air. The optical absorption α(λ) was measured in the wavelength range from 4 to 15 μm. The optical energy gap E opt. , was calculated for the three compounds. A shift of the absorption edge towards longer wavelengths with increasing Bi content was observed. (author). 7 refs, 4 figs

Electrical properties of a new sulfur-containing polymer for optoelectronic application

Science.gov (United States)

ElAkemi, ElMehdi; Jaballah, Nejmeddine; Ouada, Hafedh Ben; Majdoub, Mustapha

2015-06-01

An original polythiophene derivative was characterized to develop the optoelectronic properties of sulfur-containing π-conjugated polymer. The optical properties of the polymer were investigated by UV-visible absorption spectroscopy and atomic force microscopy. Investigations of the electrical characteristics of polymer diodes are reported. We present current-voltage characteristics and impedance spectroscopy measurements performed on partially sulfur-containing thin films in sandwich structure ITO/sulfur-containing polymer/Al. The conduction mechanisms in these layers are identified to be a space-charge-limited current. The AC electrical transport of the sulfur-containing polymer is studied as a function of frequency (100 Hz-10 MHz) and temperature in impedance spectroscopy analyses. We interpreted Cole-Cole plots in terms of the equivalent circuit model as a single parallel resistance and a capacitance network in series with a relatively small resistance. The evolution of the electrical parameters deduced from fitting of the experimental data is discussed.

GaAs optoelectronic neuron arrays

Science.gov (United States)

Lin, Steven; Grot, Annette; Luo, Jiafu; Psaltis, Demetri

1993-01-01

A simple optoelectronic circuit integrated monolithically in GaAs to implement sigmoidal neuron responses is presented. The circuit integrates a light-emitting diode with one or two transistors and one or two photodetectors. The design considerations for building arrays with densities of up to 10,000/sq cm are discussed.

Si-Based Germanium Tin Semiconductor Lasers for Optoelectronic Applications

Science.gov (United States)

Al-Kabi, Sattar H. Sweilim

Silicon-based materials and optoelectronic devices are of great interest as they could be monolithically integrated in the current Si complementary metal-oxide-semiconductor (CMOS) processes. The integration of optoelectronic components on the CMOS platform has long been limited due to the unavailability of Si-based laser sources. A Si-based monolithic laser is highly desirable for full integration of Si photonics chip. In this work, Si-based germanium-tin (GeSn) lasers have been demonstrated as direct bandgap group-IV laser sources. This opens a completely new avenue from the traditional III-V integration approach. In this work, the material and optical properties of GeSn alloys were comprehensively studied. The GeSn films were grown on Ge-buffered Si substrates in a reduced pressure chemical vapor deposition system with low-cost SnCl4 and GeH4 precursors. A systematic study was done for thin GeSn films (thickness 400 nm) with Sn composition 5 to 17.5%. The room temperature photoluminescence (PL) spectra were measured that showed a gradual shift of emission peaks towards longer wavelength as Sn composition increases. Strong PL intensity and low defect density indicated high material quality. Moreover, the PL study of n-doped samples showed bandgap narrowing compared to the unintentionally p-doped (boron) thin films with similar Sn compositions. Finally, optically pumped GeSn lasers on Si with broad wavelength coverage from 2 to 3 mum were demonstrated using high-quality GeSn films with Sn compositions up to 17.5%. The achieved maximum Sn composition of 17.5% broke the acknowledged Sn incorporation limit using similar deposition chemistry. The highest lasing temperature was measured at 180 K with an active layer thickness as thin as 270 nm. The unprecedented lasing performance is due to the achievement of high material quality and a robust fabrication process. The results reported in this work show a major advancement towards Si-based electrically pumped mid-infrared

Near infrared laser penetration and absorption in human skin

Science.gov (United States)

Nasouri, Babak; Murphy, Thomas E.; Berberoglu, Halil

2014-02-01

For understanding the mechanisms of low level laser/light therapy (LLLT), accurate knowledge of light interaction with tissue is necessary. In this paper, we present a three dimensional, multi-layer Monte Carlo simulation tool for studying light penetration and absorption in human skin. The skin is modeled as a three-layer participating medium, namely epidermis, dermis, and subcutaneous, where its geometrical and optical properties are obtained from the literature. Both refraction and reflection are taken into account at the boundaries according to Snell's law and Fresnel relations. A forward Monte Carlo method was implemented and validated for accurately simulating light penetration and absorption in absorbing and anisotropically scattering media. Local profiles of light penetration and volumetric absorption densities were simulated for uniform as well as Gaussian profile beams with different spreads at 155 mW average power over the spectral range from 1000 nm to 1900 nm. The results show the effects of beam profiles and wavelength on the local fluence within each skin layer. Particularly, the results identify different wavelength bands for targeted deposition of power in different skin layers. Finally, we show that light penetration scales well with the transport optical thickness of skin. We expect that this tool along with the results presented will aid researchers resolve issues related to dose and targeted delivery of energy in tissues for LLLT.

Electrooxidation of ethanol on Pt and PtRu surfaces investigated by ATR surface-enhanced infrared absorption spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Silva, Marcio F.; Camara, Giuseppe A., E-mail: giuseppe.silva@ufms.br [Departamento de Quimica, Universidade Federal do Mato Grosso do Sul, Campo Grande-MS (Brazil); Batista, Bruno C.; Boscheto, Emerson [Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos-SP, (Brazil); Varela, Hamilton, E-mail: varela@iqsc.usp.br [Ertl Center for Electrochemistry and Catalysis, Gwangju Institute of Science and Technology (GIST), Gwangju (Korea, Republic of)

2012-05-15

Herein, it was investigated for the first time the electro-oxidation of ethanol on Pt and PtRu electrodeposits in acidic media by using in situ surface enhanced infrared absorption spectroscopy with attenuated total reflection (ATR-SEIRAS). The experimental setup circumvents the weak absorbance signals related to adsorbed species, usually observed for rough, electrodeposited surfaces, and allows a full description of the CO coverage with the potential for both catalysts. The dynamics of adsorption-oxidation of CO was accessed by ATR-SEIRAS experiments (involving four ethanol concentrations) and correlated with expressions derived from a simple kinetic model. Kinetic analysis suggests that the growing of the CO adsorbed layer is nor influenced by the presence of Ru neither by the concentration of ethanol. The results suggest that the C-C scission is not related to the presence of Ru and probably happens at Pt sites. (author)

Infra-Red Gas Analysers of Liquid Crystal Type for Environmental Monitoring

Directory of Open Access Journals (Sweden)

V. I. Nazarov

2004-01-01

Full Text Available The paper reveals an opportunity to use infra-red gas analysers on the basis of the developed dichroic liquid crystal cells for investigation of absorption bands of various gases in the near infrared spectral region.

An ultralight and thin metasurface for radar-infrared bi-stealth applications

Science.gov (United States)

Zhang, C.; Yang, J.; Yuan, W.; Zhao, J.; Dai, J. Y.; Guo, T. C.; Liang, J.; Xu, G. Y.; Cheng, Q.; Cui, T. J.

2017-11-01

We present a thin metasurface with large microwave absorptivity and low infrared emissivity simultaneously. By properly tuning the resonance peaks and impedance of the meta-atom, broadband microwave absorptivity greater than 90% from 8.2 to 16.0 GHz is achieved. In the meantime, owing to large coverage of periodic metal patches on the top surface, low infrared emissivity is exhibited in the infrared region (IR) of 8 µm-14 µm. The excellent agreement between numerical simulation and experimental result demonstrates the good performance of the proposed metasurface. Due to the usage of polymethacrylimide (PMI) and polyethylene terephthalate (PET) as the substrate, the metasurface is especially advantageous for the light weight, making it a favorite in real engineering applications.

Advances in graphene-based optoelectronics, plasmonics and photonics

International Nuclear Information System (INIS)

Nguyen, Bich Ha; Nguyen, Van Hieu

2016-01-01

Since the early works on graphene it has been remarked that graphene is a marvelous electronic material. Soon after its discovery, graphene was efficiently utilized in the fabrication of optoelectronic, plasmonic and photonic devices, including graphene-based Schottky junction solar cells. The present work is a review of the progress in the experimental research on graphene-based optoelectronics, plasmonics and photonics, with the emphasis on recent advances. The main graphene-based optoelectronic devices presented in this review are photodetectors and modulators. In the area of graphene-based plasmonics, a review of the plasmonic nanostructures enhancing or tuning graphene-light interaction, as well as of graphene plasmons is presented. In the area of graphene-based photonics, we report progress on fabrication of different types of graphene quantum dots as well as functionalized graphene and graphene oxide, the research on the photoluminescence and fluorescence of graphene nanostructures as well as on the energy exchange between graphene and semiconductor quantum dots. In particular, the promising achievements of research on graphene-based Schottky junction solar cells is presented. (review)

Quantum of optical absorption in two-dimensional semiconductors.

Science.gov (United States)

Fang, Hui; Bechtel, Hans A; Plis, Elena; Martin, Michael C; Krishna, Sanjay; Yablonovitch, Eli; Javey, Ali

2013-07-16

The optical absorption properties of free-standing InAs nanomembranes of thicknesses ranging from 3 nm to 19 nm are investigated by Fourier transform infrared spectroscopy. Stepwise absorption at room temperature is observed, arising from the interband transitions between the subbands of 2D InAs nanomembranes. Interestingly, the absorptance associated with each step is measured to be ∼1.6%, independent of thickness of the membranes. The experimental results are consistent with the theoretically predicted absorptance quantum, AQ = πα/nc for each set of interband transitions in a 2D semiconductor, where α is the fine structure constant and nc is an optical local field correction factor. Absorptance quantization appears to be universal in 2D systems including III-V quantum wells and graphene.

Computation of Collision-Induced Absorption by Simple Molecular Complexes, for Astrophysical Applications

Science.gov (United States)

Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

2012-06-01

The interaction-induced absorption by collisional pairs of H{_2} molecules is an important opacity source in the atmospheres of various types of planets and cool stars, such as late stars, low-mass stars, brown dwarfs, cool white dwarf stars, the ambers of the smaller, burnt out main sequence stars, exoplanets, etc., and therefore of special astronomical interest The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H{_2}-H{_2}, H{_2}-He, and H{_2}-H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin. Laboratory measurements of interaction-induced absorption spectra by H{_2} pairs exist only at room temperature and below. We show that our results reproduce these measurements closely, so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures. First results for H_2-He complexes have already been applied to astrophysical models have shown great improvements in these models. L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 X. Li, K. L. C. Hunt, F. Wang, M. Abel, and L. Frommhold, Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin, Int. J. of Spect., vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, Collision-induced absorption by H{_2} pairs: From hundreds to thousands of Kelvin, J. Phys. Chem. A, 115, 6805-6812, 2011} L. Frommhold, M. Abel, F. Wang, M. Gustafsson, X. Li, and K. L. C. Hunt, "Infrared atmospheric emission and absorption by simple molecular complexes, from first principles", Mol. Phys. 108, 2265, 2010 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, Infrared absorption by collisional H_2-He complexes

Optoelectronic device with nanoparticle embedded hole injection/transport layer

Science.gov (United States)

Wang, Qingwu [Chelmsford, MA; Li, Wenguang [Andover, MA; Jiang, Hua [Methuen, MA

2012-01-03

An optoelectronic device is disclosed that can function as an emitter of optical radiation, such as a light-emitting diode (LED), or as a photovoltaic (PV) device that can be used to convert optical radiation into electrical current, such as a photovoltaic solar cell. The optoelectronic device comprises an anode, a hole injection/transport layer, an active layer, and a cathode, where the hole injection/transport layer includes transparent conductive nanoparticles in a hole transport material.

Practical opto-electronics an illustrated guide for the laboratory

CERN Document Server

Protopopov, Vladimir

2014-01-01

This book explains how to create opto-electronic systems in a most efficient way, avoiding typical mistakes. It covers light detection techniques, imaging, interferometry, spectroscopy, modulation-demodulation, heterodyning, beam steering, and many other topics common to laboratory applications. The focus is made on self-explanatory figures rather than on words. The book guides the reader through the entire process of creating problem-specific opto-electronic systems, starting from optical source, through beam transportation optical arrangement, to photodetector and data acquisition system. The relevant basics of beam propagation and computer-based raytracing routines are also explained, and sample codes are listed. the book teaches important know-how and practical tricks that are never disclosed in scientific publications.  The book can become the reader's personal adviser in the world of opto-electronics and navigator in the ocean of the market of optical components and systems. Succinct, well-illustrate...

Infrared and millimeter waves v.14 millimeter components and techniques, pt.V

CERN Document Server

Button, Kenneth J

1985-01-01

Infrared and Millimeter Waves, Volume 14: Millimeter Components and Techniques, Part V is concerned with millimeter-wave guided propagation and integrated circuits. In addition to millimeter-wave planar integrated circuits and subsystems, this book covers transducer configurations and integrated-circuit techniques, antenna arrays, optoelectronic devices, and tunable gyrotrons. Millimeter-wave gallium arsenide (GaAs) IMPATT diodes are also discussed. This monograph is comprised of six chapters and begins with a description of millimeter-wave integrated-circuit transducers, focusing on vario

The TApIR experiment. IR absorption spectra of liquid hydrogen isotopologues; Das TApIR Experiment IR-Absorptionsspektren fluessiger Wasserstoffisotopologe

Energy Technology Data Exchange (ETDEWEB)

Groessle, Robin

2015-11-27

The scope of the thesis is the infrared absorption spectroscopy of liquid hydrogen isotopologues with the tritium absorption infrared spectroscopy (TApIR) experiment at the tritium laboratory Karlsruhe (TLK). The calibration process from the sample preparation to the reference measurements are described. A further issue is the classical evaluation of FTIR absorption spectra and the extension using the rolling circle filter (RCF) including the effects on statistical and systematical errors. The impact of thermal and nuclear spin temperature on the IR absorption spectra is discussed. An empirical based modeling for the IR absorption spectra of liquid hydrogen isotopologues is performed.

Optoelectronic devices product assurance guideline for space application

Science.gov (United States)

Bensoussan, A.; Vanzi, M.

2017-11-01

New opportunities are emerging for the implementation of hardware sub-systems based on OptoElectronic Devices (OED) for space application. Since the end of this decade the main players for space systems namely designers and users including Industries, Agencies, Manufacturers and Laboratories are strongly demanding of adequate strategies to qualify and validate new optoelectronics products and sub-systems [1]. The long term space application mission will require to address either inter-satellite link (free space communication, positioning systems, tracking) or intra-satellite connectivity/flexibility/reconfigurability or high volume of data transfer between equipment installed into payload.

Resonant photoionization absorption spectra of spherical quantum dots

CERN Document Server

Bondarenko, V

2003-01-01

We study theoretically the mid-infrared photon absorption spectra due to bound-free transitions of electrons in individual spherical quantum dots. It is established that change of the dot size in one or two atomic layers or/and number of electrons by one or two can change the peak value of the absorption spectra in orders of magnitude and energy of absorbed photons by tens of millielectronvolts. The reason for this is the formation of specific free states, called resonance states. Numerical calculations are performed for quantum dots (QDs) with radius varying up to 200 A, and one to eight electrons occupying the two lowest bound states. It is supposed that realistic QD systems with resonance states would be of much advantage to design novel infrared QD photo-detectors.

Transparency of Semi-Insulating, n-Type, and p-Type Ammonothermal GaN Substrates in the Near-Infrared, Mid-Infrared, and THz Spectral Range

Directory of Open Access Journals (Sweden)

Robert Kucharski

2017-06-01

Full Text Available GaN substrates grown by the ammonothermal method are analyzed by Fast Fourier Transformation Spectroscopy in order to study the impact of doping (both n- and p-type on their transparency in the near-infrared, mid-infrared, and terahertz spectral range. It is shown that the introduction of dopants causes a decrease in transparency of GaN substrates in a broad spectral range which is attributed to absorption on free carriers (n-type samples or dopant ionization (p-type samples. In the mid-infrared the transparency cut-off, which for a semi-insulating GaN is at ~7 µm due to an absorption on a second harmonic of optical phonons, shifts towards shorter wavelengths due to an absorption on free carriers up to ~1 µm at n ~ 1020 cm−3 doping level. Moreover, a semi-insulating GaN crystal shows good transparency in the 1–10 THz range, while for n-and p-type crystal, the transparency in this spectral region is significantly quenched below 1%. In addition, it is shown that in the visible spectral region n-type GaN substrates with a carrier concentration below 1018 cm−3 are highly transparent with the absorption coefficient below 3 cm−1 at 450 nm, a satisfactory condition for light emitting diodes and laser diodes operating in this spectral range.

Tuning Infrared Plasmon Resonance of Black Phosphorene Nanoribbon with a Dielectric Interface.

Science.gov (United States)

Debu, Desalegn T; Bauman, Stephen J; French, David; Churchill, Hugh O H; Herzog, Joseph B

2018-02-19

We report on the tunable edge-plasmon-enhanced absorption of phosphorene nanoribbons supported on a dielectric substrate. Monolayer anisotropic black phosphorous (phosphorene) nanoribbons are explored for light trapping and absorption enhancement on different dielectric substrates. We show that these phosphorene ribbons support infrared surface plasmons with high spatial confinement. The peak position and bandwidth of the calculated phosphorene absorption spectra are tunable with low loss over a wide wavelength range via the surrounding dielectric environment of the periodic nanoribbons. Simulation results show strong edge plasmon modes and enhanced absorption as well as a red-shift of the peak resonance wavelength. The periodic Fabry-Perot grating model was used to analytically evaluate the absorption resonance arising from the edge of the ribbons for comparison with the simulation. The results show promise for the promotion of phosphorene plasmons for both fundamental studies and potential applications in the infrared spectral range.

Advanced Optoelectronic Components for All-Optical Networks

National Research Council Canada - National Science Library

Shapiro, Jeffrey H

2002-01-01

Under APOSR Grant F49620-96-1-0126, 'Advanced Optoelectronic Components for All-Optical Networks', we have worked to develop key technologies and components to substantially improve the performance...

Study on the mechanism of human blood glucose concentration measuring using mid-infrared spectral analysis technology

Science.gov (United States)

Li, Xiang

2016-10-01

All forms of diabetes increase the risk of long-term complications. Blood glucose monitoring is of great importance for controlling diabetes procedure, preventing the complications and improving the patient's life quality. At present, the clinical blood glucose concentration measurement is invasive and could be replaced by noninvasive spectroscopy analytical techniques. The mid-infrared spectral region contains strong characteristic and well-defined absorption bands. Therefore, mid-infrared provides an opportunity for monitoring blood glucose invasively with only a few discrete bonds. Although the blood glucose concentration measurement using mid-infrared spectroscopy has a lot of advantages, the disadvantage is also obvious. The absorption in this infrared region is fundamental molecular group vibration. Absorption intensity is very strong, especially for biological molecules. In this paper, it figures out that the osmosis rate of glucose has a certain relationship with the blood glucose concentration. Therefore, blood glucose concentration could be measured indirectly by measuring the glucose exudate in epidermis layer. Human oral glucose tolerance tests were carried out to verify the correlation of glucose exudation in shallow layer of epidermis layer and blood glucose concentration. As it has been explained above, the mid-infrared spectral region contains well-defined absorption bands, the intensity of absorption peak around 1123 cm-1 was selected to measure the glucose and that around 1170 cm-1 was selected as reference. Ratio of absorption peak intensity was recorded for each set of measurement. The effect and importance of the cleaning the finger to be measured before spectrum measuring are discussed and also verified by experiment.

High-temperature Infrared Transmission of Free-standing Diamond Films

Directory of Open Access Journals (Sweden)

HEI Li-fu

2017-02-01

Full Text Available The combination of low absorption and extreme mechanical and thermal properties make diamond a compelling choice for some more extreme far infrared (8-12 μm window applications. The optical properties of CVD diamond at elevated temperatures are critical to many of these extreme applications. The infrared transmission of free-standing diamond films prepared by DC arc plasma jet were studied at temperature varied conditions. The surface morphology, structure feature and infrared optical properties of diamond films were tested by optical microscope, X-ray diffraction, laser Raman and Fourier-transform infrared spectroscopy. The results show that the average transmittance for 8-12μm is decreased from 65.95% at 27℃ to 52.5% at 500℃,and the transmittance drop is in three stages. Corresponding to the drop of transmittance with the temperature, diamond film absorption coefficient increases with the rise of temperature. The influence of the change of surface state of diamond films on the optical properties of diamond films is significantly greater than the influence on the internal structure.

Models for infrared atmospheric radiation

Science.gov (United States)

Tiwari, S. N.

1976-01-01

Line and band models for infrared spectral absorption are discussed. Radiative transmittance and integrated absorptance of Lorentz, Doppler, and voigt line profiles were compared for a range of parameters. It was found that, for the intermediate path lengths, the combined Lorentz-Doppler (Voigt) profile is essential in calculating the atmospheric transmittance. Narrow band model relations for absorptance were used to develop exact formulations for total absorption by four wide band models. Several continuous correlations for the absorption of a wide band model were compared with the numerical solutions of the wide band models. By employing the line-by-line and quasi-random band model formulations, computational procedures were developed for evaluating transmittance and upwelling atmospheric radiance. Homogeneous path transmittances were calculated for selected bands of CO, CO2, and N2O and compared with experimental measurements. The upwelling radiance and signal change in the wave number interval of the CO fundamental band were also calculated.

Materials for optoelectronic devices, OEICs and photonics

International Nuclear Information System (INIS)

Schloetterer, H.; Quillec, M.; Greene, P.D.; Bertolotti, M.

1991-01-01

The aim of the contributors in this volume is to give a current overview on the basic properties of nonlinear optical materials for optoelectronics and integrated optics. They provide a cross-linkage between different materials (III-V, II-VI, Si-Ge, etc.), various sample dimensions (from bulk crystals to quantum dots), and a range of techniques from growth (LPE to MOMBE) and for processing from surface passivation to ion beams. Major growth techniques and materials are discussed, including the sophisticated technologies required to exploit the exciting properties of low dimensional semiconductors. These proceedings will prove an invaluable guide to the current state of optoelectronic materials development, as well as indicating the growth techniques that will be in use around the year 2000

X-RAY ABSORPTION, NUCLEAR INFRARED EMISSION, AND DUST COVERING FACTORS OF AGNs: TESTING UNIFICATION SCHEMES

Energy Technology Data Exchange (ETDEWEB)

Mateos, S.; Carrera, F. J.; Alonso-Herrero, A.; Hernán-Caballero, A.; Barcons, X. [Instituto de Física de Cantabria (CSIC-Universidad de Cantabria), E-39005, Santander (Spain); Ramos, A. Asensio; Almeida, C. Ramos [Instituto de Astrofísica de Canarias, E-38205, La Laguna, Tenerife (Spain); Watson, M. G.; Blain, A. [Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Caccianiga, A.; Ballo, L. [INAF-Osservatorio Astronomico di Brera, via Brera 28, I-20121 Milano (Italy); Braito, V., E-mail: mateos@ifca.unican.es [INAF-Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate (Italy)

2016-03-10

We present the distributions of the geometrical covering factors of the dusty tori (f{sub 2}) of active galactic nuclei (AGNs) using an X-ray selected complete sample of 227 AGNs drawn from the Bright Ultra-hard XMM-Newton Survey. The AGNs have z from 0.05 to 1.7, 2–10 keV luminosities between 10{sup 42} and 10{sup 46} erg s{sup −1}, and Compton-thin X-ray absorption. Employing data from UKIDSS, 2MASS, and the Wide-field Infrared Survey Explorer in a previous work, we determined the rest-frame 1–20 μm continuum emission from the torus, which we model here with the clumpy torus models of Nenkova et al. Optically classified type 1 and type 2 AGNs are intrinsically different, with type 2 AGNs having, on average, tori with higher f{sub 2} than type 1 AGNs. Nevertheless, ∼20% of type 1 AGNs have tori with large covering factors, while ∼23%–28% of type 2 AGNs have tori with small covering factors. Low f{sub 2} are preferred at high AGN luminosities, as postulated by simple receding torus models, although for type 2 AGNs the effect is certainly small. f{sub 2} increases with the X-ray column density, which implies that dust extinction and X-ray absorption take place in material that share an overall geometry and most likely belong to the same structure, the putative torus. Based on our results, the viewing angle, AGN luminosity, and also f{sub 2} determine the optical appearance of an AGN and control the shape of the rest-frame ∼1–20 μm nuclear continuum emission. Thus, the torus geometrical covering factor is a key ingredient of unification schemes.

Optoelectronic Devices Advanced Simulation and Analysis

CERN Document Server

Piprek, Joachim

2005-01-01

Optoelectronic devices transform electrical signals into optical signals and vice versa by utilizing the sophisticated interaction of electrons and light within micro- and nano-scale semiconductor structures. Advanced software tools for design and analysis of such devices have been developed in recent years. However, the large variety of materials, devices, physical mechanisms, and modeling approaches often makes it difficult to select appropriate theoretical models or software packages. This book presents a review of devices and advanced simulation approaches written by leading researchers and software developers. It is intended for scientists and device engineers in optoelectronics, who are interested in using advanced software tools. Each chapter includes the theoretical background as well as practical simulation results that help to better understand internal device physics. The software packages used in the book are available to the public, on a commercial or noncommercial basis, so that the interested r...

Synthesis of Mn{sub 0.04}Cu{sub 0.05}Zn{sub 0.91}O nanorod and its application in optoelectronic switching device

Energy Technology Data Exchange (ETDEWEB)

Layek, Animesh, E-mail: layekanimesh@gmail.com [Department of Physics, Bejoy Narayan Mahavidyalaya, Itachuna, Hooghly-712147 (India); Middya, Somnath [Department of Physics, Bankim Sardar College, Tangrakhali, South 24-paraganas, pin-743329 (India)

2016-05-06

The optical absorption of ZnO nanorod had been reduced by introducing Mn as doping element. In this present study the optical absorption of ZnO nanorod has been improved by simultaneous doping of the element Mn and Cu. The hydrothermal reaction was adopted for the synthesis. The electrical conductivity and the optical band gap of the Mn{sub 0.04}Cu{sub 0.05}Zn{sub 0.91}O were measured as 1.16 × 10{sup −3}Scm{sup −1} and 3.07eV respectively, assigned the semiconductor behavior. The light induced rectification in time dependent current response characteristic of Al/ Mn{sub 0.04}Cu{sub 0.05}Zn{sub 0.91}O/ITO was investigated to check the performance of the composite in opto-electronic switching device.

Optical measurements of absorption changes in two-layered diffusive media

International Nuclear Information System (INIS)

Fabbri, Francesco; Sassaroli, Angelo; Henry, Michael E; Fantini, Sergio

2004-01-01

We have used Monte Carlo simulations for a two-layered diffusive medium to investigate the effect of a superficial layer on the measurement of absorption variations from optical diffuse reflectance data processed by using: (a) a multidistance, frequency-domain method based on diffusion theory for a semi-infinite homogeneous medium; (b) a differential-pathlength-factor method based on a modified Lambert-Beer law for a homogeneous medium and (c) a two-distance, partial-pathlength method based on a modified Lambert-Beer law for a two-layered medium. Methods (a) and (b) lead to a single value for the absorption variation, whereas method (c) yields absorption variations for each layer. In the simulations, the optical coefficients of the medium were representative of those of biological tissue in the near-infrared. The thickness of the first layer was in the range 0.3-1.4 cm, and the source-detector distances were in the range 1-5 cm, which is typical of near-infrared diffuse reflectance measurements in tissue. The simulations have shown that (1) method (a) is mostly sensitive to absorption changes in the underlying layer, provided that the thickness of the superficial layer is ∼0.6 cm or less; (2) method (b) is significantly affected by absorption changes in the superficial layer and (3) method (c) yields the absorption changes for both layers with a relatively good accuracy of ∼4% for the superficial layer and ∼10% for the underlying layer (provided that the absorption changes are less than 20-30% of the baseline value). We have applied all three methods of data analysis to near-infrared data collected on the forehead of a human subject during electroconvulsive therapy. Our results suggest that the multidistance method (a) and the two-distance partial-pathlength method (c) may better decouple the contributions to the optical signals that originate in deeper tissue (brain) from those that originate in more superficial tissue layers

Hybrid optoelectronic device with multiple bistable outputs

Energy Technology Data Exchange (ETDEWEB)

Costazo-Caso, Pablo A; Jin Yiye; Gelh, Michael; Granieri, Sergio; Siahmakoun, Azad, E-mail: pcostanzo@ing.unlp.edu.are, E-mail: granieri@rose-hulma.edu, E-mail: siahmako@rose-hulma.edu [Department of Physics and Optical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803 (United States)

2011-01-01

Optoelectronic circuits which exhibit optical and electrical bistability with hysteresis behavior are proposed and experimentally demonstrated. The systems are based on semiconductor optical amplifiers (SOA), bipolar junction transistors (BJT), PIN photodiodes (PD) and laser diodes externally modulated with integrated electro-absorption modulators (LD-EAM). The device operates based on two independent phenomena leading to both electrical bistability and optical bistability. The electrical bistability is due to the series connection of two p-i-n structures (SOA, BJT, PD or LD) in reverse bias. The optical bistability is consequence of the quantum confined Stark effect (QCSE) in the multi-quantum well (MQW) structure in the intrinsic region of the device. This effect produces the optical modulation of the transmitted light through the SOA (or reflected from the PD). Finally, because the optical transmission of the SOA (in reverse bias) and the reflected light from the PD are so small, a LD-EAM modulated by the voltage across these devices are employed to obtain a higher output optical power. Experiments show that the maximum switching frequency is in MHz range and the rise/fall times lower than 1 us. The temporal response is mainly limited by the electrical capacitance of the devices and the parasitic inductances of the connecting wires. The effects of these components can be reduced in current integration technologies.

3D spectral imaging with synchrotron Fourier transform infrared spectro-microtomography

Science.gov (United States)

Michael C. Martin; Charlotte Dabat-Blondeau; Miriam Unger; Julia Sedlmair; Dilworth Y. Parkinson; Hans A. Bechtel; Barbara Illman; Jonathan M. Castro; Marco Keiluweit; David Buschke; Brenda Ogle; Michael J. Nasse; Carol J. Hirschmugl

2013-01-01

We report Fourier transform infrared spectro-microtomography, a nondestructive three-dimensional imaging approach that reveals the distribution of distinctive chemical compositions throughout an intact biological or materials sample. The method combines mid-infrared absorption contrast with computed tomographic data acquisition and reconstruction to enhance chemical...

Determination of true optical absorption and scattering coefficient of wooden cell wall substance by time-of-flight near infrared spectroscopy.

Science.gov (United States)

Kitamura, Ryunosuke; Inagaki, Tetsuya; Tsuchikawa, Satoru

2016-02-22

The true absorption coefficient (μa) and reduced scattering coefficient (μ´s) of the cell wall substance in Douglas fir were determined using time-of-flight near infrared spectroscopy. Samples were saturated with hexane, toluene or quinolone to minimize the multiple reflections of light on the boundary between pore-cell wall substance in wood. μ´s exhibited its minimum value when the wood was saturated with toluene because the refractive index of toluene is close to that of the wood cell wall substance. The optical parameters of the wood cell wall substance calculated were μa = 0.030 mm(-1) and μ´s= 18.4 mm(-1). Monte Carlo simulations using these values were in good agreement with the measured time-resolved transmittance profiles.

Phase transitions of amorphous solid acetone in confined geometry investigated by reflection absorption infrared spectroscopy.

Science.gov (United States)

Shin, Sunghwan; Kang, Hani; Kim, Jun Soo; Kang, Heon

2014-11-26

We investigated the phase transformations of amorphous solid acetone under confined geometry by preparing acetone films trapped in amorphous solid water (ASW) or CCl4. Reflection absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD) were used to monitor the phase changes of the acetone sample with increasing temperature. An acetone film trapped in ASW shows an abrupt change in the RAIRS features of the acetone vibrational bands during heating from 80 to 100 K, which indicates the transformation of amorphous solid acetone to a molecularly aligned crystalline phase. Further heating of the sample to 140 K produces an isotropic solid phase, and eventually a fluid phase near 157 K, at which the acetone sample is probably trapped in a pressurized, superheated condition inside the ASW matrix. Inside a CCl4 matrix, amorphous solid acetone crystallizes into a different, isotropic structure at ca. 90 K. We propose that the molecularly aligned crystalline phase formed in ASW is created by heterogeneous nucleation at the acetone-water interface, with resultant crystal growth, whereas the isotropic crystalline phase in CCl4 is formed by homogeneous crystal growth starting from the bulk region of the acetone sample.

Progress in the optoelectronic analog signal transfer for high energy particle detectors

International Nuclear Information System (INIS)

Tsang, T.; Radeka, V.

1992-05-01

We report the progress in the development of a radiation hard Optoelectronic analog system to transfer particle detector signals with high accuracy. We will present the motivation of this study, the operating principle of the optoelectronic system, the system noise study, the recent R ampersand D efforts on radiation effect, temperature stability, and the realization of an integrated l x l6 optical modulator. The issue of photon source for driving such a large-scale optoelectronic modulators is a major concern. We will address this problem by examining different possible photon sources and comment on other possible alternative for signal transfer

Modifying infrared scattering effects of single yeast cells with plasmonic metal mesh

Science.gov (United States)

Malone, Marvin A.; Prakash, Suraj; Heer, Joseph M.; Corwin, Lloyd D.; Cilwa, Katherine E.; Coe, James V.

2010-11-01

The scattering effects in the infrared (IR) spectra of single, isolated bread yeast cells (Saccharomyces cerevisiae) on a ZnSe substrate and in metal microchannels have been probed by Fourier transform infrared imaging microspectroscopy. Absolute extinction [(3.4±0.6)×10-7 cm2 at 3178 cm-1], scattering, and absorption cross sections for a single yeast cell and a vibrational absorption spectrum have been determined by comparing it to the scattering properties of single, isolated, latex microspheres (polystyrene, 5.0 μm in diameter) on ZnSe, which are well modeled by the Mie scattering theory. Single yeast cells were then placed into the holes of the IR plasmonic mesh, i.e., metal films with arrays of subwavelength holes, yielding "scatter-free" IR absorption spectra, which have undistorted vibrational lineshapes and a rising generic IR absorption baseline. Absolute extinction, scattering, and absorption spectral profiles were determined for a single, ellipsoidal yeast cell to characterize the interplay of these effects.

Increased Optoelectronic Quality and Uniformity of Hydrogenated p-InP Thin Films

KAUST Repository

Wang, Hsin-Ping; Sutter-Fella, Carolin M.; Lobaccaro, Peter; Hettick, Mark; Zheng, Maxwell; Lien, Der-Hsien; Miller, D. Westley; Warren, Charles W.; Roe, Ellis T; Lonergan, Mark C; Guthrey, Harvey L.; Haegel, Nancy M.; Ager, Joel W.; Carraro, Carlo; Maboudian, Roya; He, Jr-Hau; Javey, Ali

2016-01-01

The thin-film vapor-liquid-solid (TF-VLS) growth technique presents a promising route for high quality, scalable and cost-effective InP thin films for optoelectronic devices. Towards this goal, careful optimization of material properties and device performance is of utmost interest. Here, we show that exposure of polycrystalline Zn-doped TF-VLS InP to a hydrogen plasma (in the following referred to as hydrogenation) results in improved optoelectronic quality as well as lateral optoelectronic uniformity. A combination of low temperature photoluminescence and transient photocurrent spectroscopy were used to analyze the energy position and relative density of defect states before and after hydrogenation. Notably, hydrogenation reduces the intra-gap defect density by one order of magnitude. As a metric to monitor lateral optoelectronic uniformity of polycrystalline TF-VLS InP, photoluminescence and electron beam induced current mapping reveal homogenization of the grain versus grain boundary upon hydrogenation. At the device level, we measured more than 260 TF-VLS InP solar cells before and after hydrogenation to verify the improved optoelectronic properties. Hydrogenation increased the average open-circuit voltage (VOC) of individual TF-VLS InP solar cells by up to 130 mV, and reduced the variance in VOC for the analyzed devices.

Increased Optoelectronic Quality and Uniformity of Hydrogenated p-InP Thin Films

KAUST Repository

Wang, Hsin-Ping

2016-06-08

The thin-film vapor-liquid-solid (TF-VLS) growth technique presents a promising route for high quality, scalable and cost-effective InP thin films for optoelectronic devices. Towards this goal, careful optimization of material properties and device performance is of utmost interest. Here, we show that exposure of polycrystalline Zn-doped TF-VLS InP to a hydrogen plasma (in the following referred to as hydrogenation) results in improved optoelectronic quality as well as lateral optoelectronic uniformity. A combination of low temperature photoluminescence and transient photocurrent spectroscopy were used to analyze the energy position and relative density of defect states before and after hydrogenation. Notably, hydrogenation reduces the intra-gap defect density by one order of magnitude. As a metric to monitor lateral optoelectronic uniformity of polycrystalline TF-VLS InP, photoluminescence and electron beam induced current mapping reveal homogenization of the grain versus grain boundary upon hydrogenation. At the device level, we measured more than 260 TF-VLS InP solar cells before and after hydrogenation to verify the improved optoelectronic properties. Hydrogenation increased the average open-circuit voltage (VOC) of individual TF-VLS InP solar cells by up to 130 mV, and reduced the variance in VOC for the analyzed devices.

Infrared radiation models for atmospheric methane

Science.gov (United States)

Cess, R. D.; Kratz, D. P.; Caldwell, J.; Kim, S. J.

1986-01-01

Mutually consistent line-by-line, narrow-band and broad-band infrared radiation models are presented for methane, a potentially important anthropogenic trace gas within the atmosphere. Comparisons of the modeled band absorptances with existing laboratory data produce the best agreement when, within the band models, spurious band intensities are used which are consistent with the respective laboratory data sets, but which are not consistent with current knowledge concerning the intensity of the infrared fundamental band of methane. This emphasizes the need for improved laboratory band absorptance measurements. Since, when applied to atmospheric radiation calculations, the line-by-line model does not require the use of scaling approximations, the mutual consistency of the band models provides a means of appraising the accuracy of scaling procedures. It is shown that Curtis-Godson narrow-band and Chan-Tien broad-band scaling provide accurate means of accounting for atmospheric temperature and pressure variations.

Opto-electronic device for frequency standard generation and terahertz-range optical demodulation based on quantum interference

Science.gov (United States)

Georgiades, Nikos P.; Polzik, Eugene S.; Kimble, H. Jeff

1999-02-02

An opto-electronic system and technique for comparing laser frequencies with large frequency separations, establishing new frequency standards, and achieving phase-sensitive detection at ultra high frequencies. Light responsive materials with multiple energy levels suitable for multi-photon excitation are preferably used for nonlinear mixing via quantum interference of different excitation paths affecting a common energy level. Demodulation of a carrier with a demodulation frequency up to 100's THZ can be achieved for frequency comparison and phase-sensitive detection. A large number of materials can be used to cover a wide spectral range including the ultra violet, visible and near infrared regions. In particular, absolute frequency measurement in a spectrum from 1.25 .mu.m to 1.66 .mu.m for fiber optics can be accomplished with a nearly continuous frequency coverage.

Design of a sector bowtie nano-rectenna for optical power and infrared detection

Science.gov (United States)

Wang, Kai; Hu, Haifeng; Lu, Shan; Guo, Lingju; He, Tao

2015-10-01

We designed a sector bowtie nanoantenna integrated with a rectifier (Au-TiO x -Ti diode) for collecting infrared energy. The optical performance of the metallic bowtie nanoantenna was numerically investigated at infrared frequencies (5-30 μm) using three-dimensional frequency-domain electromagnetic field calculation software based on the finite element method. The simulation results indicate that the resonance wavelength and local field enhancement are greatly affected by the shape and size of the bowtie nanoantenna, as well as the relative permittivity and conductivity of the dielectric layer. The output current of the rectified nano-rectenna is substantially at nanoampere magnitude with an electric field intensity of 1 V/m. Moreover, the power conversion efficiency for devices with three different substrates illustrates that a substrate with a larger refractive index yields a higher efficiency and longer infrared response wavelength. Consequently, the optimized structure can provide theoretical support for the design of novel optical rectennas and fabrication of optoelectronic devices.

Electromagnetic radiation energy arrangement. [coatings for solar energy absorption and infrared reflection

Science.gov (United States)

Lipkis, R. R.; Vehrencamp, J. E. (Inventor)

1965-01-01

A solar energy collector and infrared energy reflector is described which comprises a vacuum deposited layer of aluminum of approximately 200 to 400 Angstroms thick on one side of a substrate. An adherent layer of titanium with a thickness of between 800 and 1000 Angstroms is vacuum deposited on the aluminum substrate and is substantially opaque to solar energy and substantially transparent to infrared energy.

High bandgap III-V alloys for high efficiency optoelectronics

Energy Technology Data Exchange (ETDEWEB)

Alberi, Kirstin; Mascarenhas, Angelo; Wanlass, Mark

2017-01-10

High bandgap alloys for high efficiency optoelectronics are disclosed. An exemplary optoelectronic device may include a substrate, at least one Al.sub.1-xIn.sub.xP layer, and a step-grade buffer between the substrate and at least one Al.sub.1-xIn.sub.xP layer. The buffer may begin with a layer that is substantially lattice matched to GaAs, and may then incrementally increase the lattice constant in each sequential layer until a predetermined lattice constant of Al.sub.1-xIn.sub.xP is reached.

Toward high-resolution optoelectronic retinal prosthesis

Science.gov (United States)

Palanker, Daniel; Huie, Philip; Vankov, Alexander; Asher, Alon; Baccus, Steven

2005-04-01

It has been already demonstrated that electrical stimulation of retina can produce visual percepts in blind patients suffering from macular degeneration and retinitis pigmentosa. Current retinal implants provide very low resolution (just a few electrodes), while several thousand pixels are required for functional restoration of sight. We present a design of the optoelectronic retinal prosthetic system that can activate a retinal stimulating array with pixel density up to 2,500 pix/mm2 (geometrically corresponding to a visual acuity of 20/80), and allows for natural eye scanning rather than scanning with a head-mounted camera. The system operates similarly to "virtual reality" imaging devices used in military and medical applications. An image from a video camera is projected by a goggle-mounted infrared LED-LCD display onto the retina, activating an array of powered photodiodes in the retinal implant. Such a system provides a broad field of vision by allowing for natural eye scanning. The goggles are transparent to visible light, thus allowing for simultaneous utilization of remaining natural vision along with prosthetic stimulation. Optical control of the implant allows for simple adjustment of image processing algorithms and for learning. A major prerequisite for high resolution stimulation is the proximity of neural cells to the stimulation sites. This can be achieved with sub-retinal implants constructed in a manner that directs migration of retinal cells to target areas. Two basic implant geometries are described: perforated membranes and protruding electrode arrays. Possibility of the tactile neural stimulation is also examined.

High efficiency optoelectronic terahertz sources

Science.gov (United States)

Lampin, Jean-François; Peytavit, Emilien; Akalin, Tahsin; Ducournau, G.; Hindle, Francis; Mouret, Gael

2010-08-01

We have developed a new generation of optoelectronic large bandwidth terahertz sources based on TEM horn antennas monolithically integrated with several types of photodetectors: low-temperature grown GaAs (LTG-GaAs) planar photoconductors, vertically integrated LTG-GaAs photoconductors on silicon substrate and uni-travelling-carrier photodiodes. Results of pulsed (time-domain) and photomixing (CW, frequency domain) experiments are presented.

Critical coupling using the hexagonal boron nitride crystals in the mid-infrared range

Energy Technology Data Exchange (ETDEWEB)

Wu, Jipeng; Wang, Hengliang; Wen, Shuangchun [Key Laboratory for Micro-/Nano-Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082 (China); Jiang, Leyong; Guo, Jun; Dai, Xiaoyu [SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Xiang, Yuanjiang, E-mail: xiangyuanjiang@126.com [Key Laboratory for Micro-/Nano-Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082 (China); SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China)

2016-05-28

We theoretically demonstrate the perfect absorption phenomena in the hexagonal boron nitride (hBN) crystals in the mid-infrared wavelength ranges by means of critical coupling with a one-dimensional photonic crystal spaced by the air. Different from the polymer absorbing layer composed by a metal-dielectric composite film, the hyperbolic dispersion characteristics of hBN can meet the condition of critical coupling and achieve the total absorption in the mid-infrared wavelength ranges. However, the critical coupling phenomenon can only appear in the hBN crystals with the type II dispersion. Moreover, we discuss the influence of the thickness of hBN, the incident angle, and the thickness and permittivity of the space dielectric on the total absorption. Ultimately, the conditions for absorption enhancement and the optimization methods of perfect absorption are proposed, and the design rules for a totally absorbing system under the different conditions are achieved.

Carbon dioxide adsorption on a ZnO(101[combining macron]0) substrate studied by infrared reflection absorption spectroscopy.

Science.gov (United States)

Buchholz, Maria; Weidler, Peter G; Bebensee, Fabian; Nefedov, Alexei; Wöll, Christof

2014-01-28

The adsorption of carbon dioxide on the mixed-terminated ZnO(101[combining macron]0) surface of a bulk single crystal was studied by UHV Infrared Reflection Absorption Spectroscopy (IRRAS). In contrast to metals, the classic surface selection rule for IRRAS does not apply to bulk oxide crystals, and hence vibrational bands can also be observed for s-polarized light. Although this fact substantially complicates data interpretation, a careful analysis allows for a direct determination of the adsorbate geometry. Here, we demonstrate the huge potential of IR-spectroscopy for investigations on oxide single crystal surfaces by considering all three components of the incident polarized light separately. We find that the tridentate (surface) carbonate is aligned along the [0001] direction. A comparison to data reported previously for CO2 adsorbed on the surfaces of ZnO nanoparticles provides important insight into the role of defects in the surface chemistry of powder particles.

Infrared spectroscopic study of the synthetic Mg-Ni talc series

Science.gov (United States)

Blanchard, Marc; Méheut, Merlin; Delon, Louise; Poirier, Mathilde; Micoud, Pierre; Le Roux, Christophe; Martin, François

2018-05-01

Five talc samples [(Mg,Ni)3Si4O10(OH)2] covering the entire Mg-Ni solid solution were synthesized following a recently developed and patented process (Dumas et al., Process for preparing a composition comprising synthetic mineral particles and composition, 2013a; Procédé de préparation d'une composition comprenant des particules minérales synthétiques et composition, 2013b), which produces sub-micron talc particles replying to industrial needs. Near- and mid-infrared spectra were collected and compared to infrared spectra modeled from first-principles calculations based on density functional theory. The good agreement between experimental and theoretical spectra allowed assigning unambiguously all absorption bands. We focused in particular on the four main OH stretching bands, which represent good probes of their local physical and chemical environment. The description of the vibrational modes at the origin of these absorption bands and the theoretical determination of absorption coefficients provide a firm basis for quantifying the talc chemical composition from infrared spectroscopy and for discussing the distribution of divalent cations in the octahedral sheet. Results confirm that these synthetic talc samples have a similar structure as natural talc, with a random distribution of Mg and Ni atoms. They only differ from natural talc by their hydrophilic character, which is due to their large proportion of reactive sites on sheet edges due to sub-micronic size of the particles. Therefore, the contribution on infrared spectra of hydroxyls adsorbed on edge sites has also been investigated by computing the infrared signature of hydroxyls of surface models.

Broadband infrared metamaterial absorber based on anodic aluminum oxide template

Science.gov (United States)

Yang, Jingfan; Qu, Shaobo; Ma, Hua; Wang, Jiafu; Yang, Shen; Pang, Yongqiang

2018-05-01

In this work, a broadband infrared metamaterial absorber is proposed based on trapezoid-shaped anodic aluminum oxide (AAO) template. Unlike traditional metamaterial absorber constructed from metal-dielectric-metal sandwich structure, our proposed absorber is composed of trapezoid-shaped AAO template with metallic nanowires inside. The infrared absorption efficiency is numerically calculated and the mechanism analysis is given in the paper. Owing to the superposition of multiple resonances produced by the nanowires with different heights, the infrared metamatrial absorber can keep high absorption efficiency during broad working wavelength band from 3.4 μm to 6.1 μm. In addition, the resonance wavelength is associated with the height of nanowires, which indicates that the resonance wavelength can be modulated flexibly through changing the heights of nanowires. This kind of design can also be adapted to other wavelength regions.

The tunneling magnetoresistance and spin-polarized optoelectronic properties of graphyne-based molecular magnetic tunnel junctions

International Nuclear Information System (INIS)

Yang, Zhi; Ouyang, Bin; Lan, Guoqing; Xu, Li-Chun; Liu, Ruiping; Liu, Xuguang

2017-01-01

Using density functional theory and the non-equilibrium Green’s function method, we investigate the spin-dependent transport and optoelectronic properties of the graphyne-based molecular magnetic tunnel junctions (MMTJs). We find that these MMTJs exhibit an outstanding tunneling magnetoresistance (TMR) effect. The TMR value is as high as 10 6 %. When the magnetization directions of two electrodes are antiparallel under positive or negative bias voltages, two kinds of pure spin currents can be obtained in the systems. Furthermore, under the irradiation of infrared, visible or ultraviolet light, spin-polarized photocurrents can be generated in the MMTJs, but the corresponding microscopic mechanisms are different. More importantly, if the magnetization directions of two electrodes are antiparallel, the photocurrents with different spins are spatially separated, appearing at different electrodes. This phenomenon provides a new way to simultaneously generate two spin currents. (paper)

Tunable electromagnetically induced absorption based on graphene

Science.gov (United States)

Cao, Maoyong; Wang, Tongling; Zhang, Huiyun; Zhang, Yuping

2018-04-01

In this paper, an electronically induced absorption (EIA) structure based on graphene at the infrared frequency is proposed. A pair of nanorods is coupled to a ring resonator, resulting in electronically induced transparency (EIT), and then, Babinet's principle is applied to transform the EIT structure into an EIA structure. Based on the bright and dark modes of the coupling schemes, the adjustment of the coupling strength between the dark and bright modes can be achieved by changing the asymmetry degree. In addition, the transparency window and the absorption peak can be tuned by changing the Fermi energy of graphene. This graphene-based EIA structure can develop the path in narrow-band filtering and, absorptive switching in the future.

Mid-infrared supercontinuum generation in the fingerprint region

DEFF Research Database (Denmark)

Møller, Uffe Visbech; Petersen, Christian Rosenberg; Kubat, Irnis

The mid-infrared spectral region is of great technical and scientific interest because most molecules display fundamental vibrational absorptions in this region, leaving distinctive spectral fingerprints. Here, we demonstrate experimentally that launching intense ultra-short pulses with a central...... the potential of fibres to emit across the mid-infrared molecular fingerprint region, which is of key importance for applications such as early cancer diagnostics, gas sensing and food quality control....

ABSORPTION-SPECTRA OF HUMAN FETAL AND ADULT OXYHEMOGLOBIN, DE-OXYHEMOGLOBIN, CARBOXYHEMOGLOBIN, AND METHEMOGLOBIN

NARCIS (Netherlands)

ZIJLSTRA, WG; MEEUWSENVANDERROEST, WP

We determined the millimolar absorptivities of the four clinically relevant derivatives of fetal and adult human hemoglobin in the visible and near-infrared spectral range (450-1000 nm). As expected, spectral absorption curves of similar shape were found, but the small differences between fetal and

Optoelectronics in TESLA, LHC and pi-of-the-sky experiments

CERN Document Server

Romaniuk, Ryszard; Simrock, Stefan; Wrochna, Grzegorz

2004-01-01

Optical and optoelectronics technologies are more and more widely used in the biggest world experiments of high energy and nuclear physics, as well as in the astronomy. The paper is a kind of a broad digest describing the usage of optoelectronics is such experiments and information about some of the involved teams. The described experiments include: TESLA linear accelerator and FEL, Compact Muon Solenoid at LHC and recently started pi-of-the-sky global gamma ray bursts (with associated optical flashes) observation experiment. Optoelectronics and photonics offer several key features which are either extending the technical parameters of existing solutions or adding quite new practical application possibilities. Some of these favorable features of photonic systems are: high selectivity of optical sensors, immunity to some kinds of noise processes, extremely broad bandwidth exchangeable for either terabit rate transmission or ultrashort pulse generation, parallel image processing capability, etc. The following g...

The Cellulose Nanofibers for Optoelectronic Conversion and Energy Storage

Directory of Open Access Journals (Sweden)

Yongfeng Luo

2014-01-01

Full Text Available Cellulose widely exists in plant tissues. Due to the large pores between the cellulose units, the regular paper is nontransparent that cannot be used in the optoelectronic devices. But some chemical and physical methods such as 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO oxidation can be used to improve the pores scale between the cellulose units to reach nanometer level. The cellulose nanofibers (CNFs have good mechanical strength, flexibility, thermostability, and low thermal expansion. The paper made of these nanofibers represent a kind of novel nanostructured material with ultrahigh transparency, ultrahigh haze, conductivity, biodegradable, reproducible, low pollution, environment friendly and so on. These advantages make the novel nanostructured paper apply in the optoelectronic device possible, such as electronics energy storage devices. This kind of paper is considered most likely to replace traditional materials like plastics and glass, which is attracting widespread attention, and the related research has also been reported. The purpose of this paper is to review CNFs which are applied in optoelectronic conversion and energy storage.

Design of a high-resolution optoelectronic retinal prosthesis.

Science.gov (United States)

Palanker, Daniel; Vankov, Alexander; Huie, Phil; Baccus, Stephen

2005-03-01

It has been demonstrated that electrical stimulation of the retina can produce visual percepts in blind patients suffering from macular degeneration and retinitis pigmentosa. However, current retinal implants provide very low resolution (just a few electrodes), whereas at least several thousand pixels would be required for functional restoration of sight. This paper presents the design of an optoelectronic retinal prosthetic system with a stimulating pixel density of up to 2500 pix mm(-2) (corresponding geometrically to a maximum visual acuity of 20/80). Requirements on proximity of neural cells to the stimulation electrodes are described as a function of the desired resolution. Two basic geometries of sub-retinal implants providing required proximity are presented: perforated membranes and protruding electrode arrays. To provide for natural eye scanning of the scene, rather than scanning with a head-mounted camera, the system operates similar to 'virtual reality' devices. An image from a video camera is projected by a goggle-mounted collimated infrared LED-LCD display onto the retina, activating an array of powered photodiodes in the retinal implant. The goggles are transparent to visible light, thus allowing for the simultaneous use of remaining natural vision along with prosthetic stimulation. Optical delivery of visual information to the implant allows for real-time image processing adjustable to retinal architecture, as well as flexible control of image processing algorithms and stimulation parameters.

Design of a high-resolution optoelectronic retinal prosthesis

Science.gov (United States)

Palanker, Daniel; Vankov, Alexander; Huie, Phil; Baccus, Stephen

2005-03-01

It has been demonstrated that electrical stimulation of the retina can produce visual percepts in blind patients suffering from macular degeneration and retinitis pigmentosa. However, current retinal implants provide very low resolution (just a few electrodes), whereas at least several thousand pixels would be required for functional restoration of sight. This paper presents the design of an optoelectronic retinal prosthetic system with a stimulating pixel density of up to 2500 pix mm-2 (corresponding geometrically to a maximum visual acuity of 20/80). Requirements on proximity of neural cells to the stimulation electrodes are described as a function of the desired resolution. Two basic geometries of sub-retinal implants providing required proximity are presented: perforated membranes and protruding electrode arrays. To provide for natural eye scanning of the scene, rather than scanning with a head-mounted camera, the system operates similar to 'virtual reality' devices. An image from a video camera is projected by a goggle-mounted collimated infrared LED-LCD display onto the retina, activating an array of powered photodiodes in the retinal implant. The goggles are transparent to visible light, thus allowing for the simultaneous use of remaining natural vision along with prosthetic stimulation. Optical delivery of visual information to the implant allows for real-time image processing adjustable to retinal architecture, as well as flexible control of image processing algorithms and stimulation parameters.

Far-infared spectroscopic observations with a Balloon-Borne infrared telescope

International Nuclear Information System (INIS)

Maihara, Toshinori; Takami, Hideki; Mizutani, Kohei

1986-01-01

The first observations of far-infrared celestial objects using the 50-cm Balloon-Borne Infrared Telescope were made in Alice Springs, Australia. Far-infrared spectrophotometric data between 45 and 115 μm were taken for the Orion-KL region, Saturn and a southern H II region RCW 38. The data including high excitation transition lines of CO for Orion-KL, O III lines for RCW 38 and a PH 3 absorption feature of Saturn will be presented. (author)

A NEW GAS CELL FOR HIGH-PRECISION DOPPLER MEASUREMENTS IN THE NEAR-INFRARED

International Nuclear Information System (INIS)

Valdivielso, L.; Esparza, P.; MartIn, E. L.; Maukonen, D.; Peale, R. E.

2010-01-01

High-resolution spectroscopy in the near-infrared could become the leading method for discovering extra-solar planets around very low mass stars and brown dwarfs. In order to help to achieve an accuracy of ∼m s -1 , we are developing a gas cell which consists of a mixture of gases whose absorption spectral lines span all over the near-infrared region. We present the most promising mixture, made of acetylene, nitrous oxide, ammonia, chloromethanes, and hydrocarbons. The mixture is contained in a small size 13 cm long gas cell and covers most of the H and K bands. It also shows small absorptions in the J band, but they are few and not sharp enough for near-infrared wavelength calibration. We describe the working method and experiments, and compare our results with the state of the art for near-infrared gas cells.

Infrared spectra of jennite and tobermorite from first-principles

Energy Technology Data Exchange (ETDEWEB)

Vidmer, Alexandre, E-mail: alexandre@vidmer.com; Sclauzero, Gabriele; Pasquarello, Alfredo

2014-06-01

The infrared absorption spectra of jennite, tobermorite 14 Å, anomalous tobermorite 11 Å, and normal tobermorite 11 Å are simulated within a density-functional-theory scheme. The atomic coordinates and the cell parameters are optimized resulting in structures which agree with previous studies. The vibrational frequencies and modes are obtained for each mineral. The vibrational density of states is analyzed through extensive projections on silicon tetrahedra, oxygen atoms, OH groups, and water molecules. The coupling with the electric field is achieved through the use of density functional perturbation theory, which yields Born effective charges and dielectric constants. The simulated absorption spectra reproduce well the experimental spectra, thereby allowing for a detailed interpretation of the spectral features in terms of the underlying vibrational modes. In the far-infrared part of the absorption spectra, the interplay between Ca and Si related vibrations leads to differences which are sensitive to the calcium/silicon ratio of the mineral.

Absorption of human skin and its detecting platform in the process of laser cosmetology

Science.gov (United States)

Zhang, Yong-Lin; Ouyang, Li; Wang, Yang

2000-10-01

Because of the melanin, hemoglobin and water molecules, etc. contained, light absorption of human skin tissue changes with wavelength of light. This is the principle used in laser cosmetology for treating pigment diseases and vascular lesion diseases as well as skin decoration such as body tattooing, eyebrow tattooing, etc. The parameters of treatment used in laser cosmetology principally come from the research of the skin tissue optical characteristics of whites, and it is not suitable for the Oriental. The absorption spectrum of yellow race alive skin has been researched. The detecting platform for use in the measuring of vivi-tissue absorption spectrum has been developed which using opto-electronic nondestructive testing and virtual instrument techniques. The degree of pathological changes of skin can be detected by this platform also, thus the shortcoming of dosage selection in laser clinical treatments which have been decided only by naked eye observation and past experience of doctors can be solved.

Vibrational Spectroscopy of Intramolecular Hydrogen Bonds in the Infrared and Near-Infrared Regions

DEFF Research Database (Denmark)

Schrøder, Sidsel Dahl

and 1,4-diaminobutane). Experimentally, the hydrogen bonds have been studied with vibrational spectroscopy in the infrared and near-infrared regions. The focus is primarily on spectra recorded in the near-infrared regions, which in these studies are dominated by O-H and N-H stretching overtones....... Overtone spectra have been recorded with intracavity laser photoacoustic laser spectroscopy and conventional long path absorption spectroscopy. Theoretically, a combination of electronic structure calculations and local mode models have been employed to guide the assignment of bands in the vibrational......,4-diaminobutane, no sign of intramolecular N-H···N hydrogen bonds were identified in the overtone spectra. However, theoretical analyzes indicate that intramolecular N-H···N hydrogen bonds are present in all three diamines if two hydrogen atoms on one of the methylene groups are substituted with triuoromethyl...

Standard cell-based implementation of a digital optoelectronic neural-network hardware.

Science.gov (United States)

Maier, K D; Beckstein, C; Blickhan, R; Erhard, W

2001-03-10

A standard cell-based implementation of a digital optoelectronic neural-network architecture is presented. The overall structure of the multilayer perceptron network that was used, the optoelectronic interconnection system between the layers, and all components required in each layer are defined. The design process from VHDL-based modeling from synthesis and partly automatic placing and routing to the final editing of one layer of the circuit of the multilayer perceptrons are described. A suitable approach for the standard cell-based design of optoelectronic systems is presented, and shortcomings of the design tool that was used are pointed out. The layout for the microelectronic circuit of one layer in a multilayer perceptron neural network with a performance potential 1 magnitude higher than neural networks that are purely electronic based has been successfully designed.

Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

Science.gov (United States)

Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

2007-12-01

Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (Petroleo (IMP) and CENICA.

Femtosecond infrared spectroscopy: study, development and applications

International Nuclear Information System (INIS)

Bonvalet, Adeline

1997-01-01

This work has been devoted to the development and the applications of a new technique of infrared (5-20 μm) spectroscopy allowing a temporal resolution of 100 fs. This technique relies on a source of ultrashort infrared pulses obtained by frequency mixing in a nonlinear material. In particular, the optical rectification of 12-fs visible pulses in gallium arsenide has allowed us to obtain 40-fs infrared pulses with a spectrum extending from 5 pm up to 15 μm. Spectral resolution has been achieved by Fourier transform spectroscopy, using a novel device we have called Diffracting FTIR. These developments allow to study inter-subband transitions in quantum-well structures. The inter-subband relaxation time has been measured by a pump-probe experiment, in which the sample was excited with a visible pulse, and the variations of inter-subband absorption probed with an infrared pulse. Besides, we have developed a method of coherent emission spectroscopy allowing to monitor the electric field emitted by coherent charge oscillations in quantum wells. The decay of the oscillations due to the loss of coherence between excited levels yields a direct measurement of the dephasing time between these levels. Other applications include biological macromolecules like reaction centers of photosynthetic bacteria. We have shown that we were able to monitor variations of infrared absorption of about 10 -4 optical densities with a temporal resolution of 100 fs. This would constitute a relevant tool to study the role of molecular vibrations during the primary steps of biological processes. (author) [fr

Near-Infrared Spectroscopic Study of Chlorite Minerals

OpenAIRE

Min Yang; Meifang Ye; Haihui Han; Guangli Ren; Ling Han; Zhuan Zhang

2018-01-01

The mineral chemistry of twenty chlorite samples from the United States Geological Survey (USGS) spectral library and two other regions, having a wide range of Fe and Mg contents and relatively constant Al and Si contents, was studied via infrared (IR) spectroscopy, near-infrared (NIR) spectroscopy, and X-ray fluorescence (XRF) analysis. Five absorption features of the twenty samples near 4525, 4440, 4361, 4270, and 4182 cm−1 were observed, and two diagnostic features at 4440 and 4280 cm−1 we...

Effect of Varying Pnictogen Elements (Pn=N, P, As, Sb, Bi) on the Optoelectronic Properties of SrZn2Pn2

Science.gov (United States)

Murtaza, G.; Yousaf, N.; Laref, A.; Yaseen, M.

2018-03-01

Pnictogen-based Zintl compounds have fascinating properties. Nowadays these compounds have gained exceptional interest in thermoelectric and optoelectronic fields. Therefore, in this work the structural, electronic and optical properties of SrZn2Pn2 (Pn=N, P, As, Sb, Bi) compounds were studied using state-of-the-art density functional theory. The optimised lattice parameters (ɑ, c, c/ɑ and bond lengths) are consistent with the experimental results. The bulk moduli and c/a showed a decrease when changing the Pnictogen (Pn) anion from N to Bi in SrZn2Pn2 (Pn=N, P, As, Sb, Bi). The modified Becke-Johnson potential is used for band structure calculations. All compounds show semiconducting behaviour except SrZn2Bi2, which is metallic. Pn-p, Zn-d and Sr-d play an important role in defining the electronic structure of the compounds. The optical conductivity and absorption coefficient strength are high in visible and ultraviolet regions. These band structures and optical properties clearly show that SrZn2Pn2 compounds are potential candidates in the fields of optoelectronic and photonic devices.

Progress in complementary metal–oxide–semiconductor silicon photonics and optoelectronic integrated circuits

International Nuclear Information System (INIS)

Chen Hongda; Zhang Zan; Huang Beiju; Mao Luhong; Zhang Zanyun

2015-01-01

Silicon photonics is an emerging competitive solution for next-generation scalable data communications in different application areas as high-speed data communication is constrained by electrical interconnects. Optical interconnects based on silicon photonics can be used in intra/inter-chip interconnects, board-to-board interconnects, short-reach communications in datacenters, supercomputers and long-haul optical transmissions. In this paper, we present an overview of recent progress in silicon optoelectronic devices and optoelectronic integrated circuits (OEICs) based on a complementary metal–oxide–semiconductor-compatible process, and focus on our research contributions. The silicon optoelectronic devices and OEICs show good characteristics, which are expected to benefit several application domains, including communication, sensing, computing and nonlinear systems. (review)

Structural and Optoelectronic Properties of Cubic CsPbF3 for Novel Applications

International Nuclear Information System (INIS)

Murtaza, G.; Ahmad, Iftikhar; Maqbool, M.; Rahnamaye Aliabad, H. A.; Afaq, A.

2011-01-01

Chemical bonding as well as structural, electronic and optical properties of CsPbF 3 are calculated using the highly accurate full potential linearized augmented plane-wave method within the framework of density functional theory (DFT). The calculated lattice constant is found to be in good agreement with the experimental results. The electron density plots reveal strong ionic bonding in Cs-F and strong covalent bonding in Pb-F. The calculations show that the material is a direct and wide bandgap semiconductor with a fundamental gap at the R-symmetry point. Optical properties such as the real and imaginary parts of the dielectric function, refractive index, extinction coefficient, reflectivity, optical conductivity and absorption coefficient are also calculated. Based on the calculated wide and direct bandgap, as well as other optical properties of the compound, it is predicted that CsPbF 3 is suitable for optoelectronic devices and anti-reflecting coatings. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Structure and dynamics in liquid water from x-ray absorption spectroscopy

International Nuclear Information System (INIS)

Wernet, Philippe

2009-01-01

Oxygen K-edge x-ray absorption spectra of water are discussed. The spectra of gas-phase water, liquid water and ice illustrate the sensitivity of oxygen K-edge x-ray absorption spectroscopy to hydrogen bonding in water. Transmission mode spectra of amorphous and crystalline ice are compared to x-ray Raman spectra of ice. The good agreement consolidates the experimental spectrum of crystalline ice and represents an incentive for theoretical calculations of the oxygen K-edge absorption spectrum of crystalline ice. Time-resolved infrared-pump and x-ray absorption probe results are finally discussed in the light of this structural interpretation.

Infrared laser spectroscopic trace gas sensing

Science.gov (United States)

Sigrist, Markus

2016-04-01

Chemical sensing and analyses of gas samples by laser spectroscopic methods are attractive owing to several advantages such as high sensitivity and specificity, large dynamic range, multi-component capability, and lack of pretreatment or preconcentration procedures. The preferred wavelength range comprises the fundamental molecular absorption range in the mid-infared between 3 and 15 μm, whereas the near-infrared range covers the (10-100 times weaker) higher harmonics and combination bands. The availability of near-infrared and, particularly, of broadly tunable mid-infrared sources like external cavity quantum cascade lasers (EC-QCLs), interband cascade lasers (ICLs), difference frequency generation (DFG), optical parametric oscillators (OPOs), recent developments of diode-pumped lead salt semiconductor lasers, of supercontinuum sources or of frequency combs have eased the implementation of laser-based sensing devices. Sensitive techniques for molecular absorption measurements include multipass absorption, various configurations of cavity-enhanced techniques such as cavity ringdown (CRD), or of photoacoustic spectroscopy (PAS) including quartz-enhanced (QEPAS) or cantilever-enhanced (CEPAS) techniques. The application requirements finally determine the optimum selection of laser source and detection scheme. In this tutorial talk I shall discuss the basic principles, present various experimental setups and illustrate the performance of selected systems for chemical sensing of selected key atmospheric species. Applications include an early example of continuous vehicle emission measurements with a mobile CO2-laser PAS system [1]. The fast analysis of C1-C4 alkanes at sub-ppm concentrations in gas mixtures is of great interest for the petrochemical industry and was recently achieved with a new type of mid-infrared diode-pumped piezoelectrically tuned lead salt vertical external cavity surface emitting laser (VECSEL) [2]. Another example concerns measurements on short

Mid-infrared GaSb-based resonant tunneling diode photodetectors for gas sensing applications

Science.gov (United States)

Rothmayr, F.; Pfenning, A.; Kistner, C.; Koeth, J.; Knebl, G.; Schade, A.; Krueger, S.; Worschech, L.; Hartmann, F.; Höfling, S.

2018-04-01

We present resonant tunneling diode-photodetectors (RTD-PDs) with GaAs0.15Sb0.85/AlAs0.1Sb0.9 double barrier structures combined with an additional quaternary Ga0.64In0.36As0.33Sb0.67 absorption layer covering the fingerprint absorption lines of various gases in the mid-infrared wavelength spectral region. The absorption layer cut-off wavelength is determined to be 3.5 μm, and the RTD-PDs show peak-to-valley current ratios up to 4.3 with a peak current density of 12 A/cm-2. The incorporation of the quaternary absorption layer enables the RTD-PDs to be sensitive to illumination with light up to the absorption lines of HCl at 3395 nm. At this wavelength, the detector shows a responsivity of 6.3 mA/W. At the absorption lines of CO2 and CO at 2004 nm and 2330 nm, respectively, the RTD-PDs reach responsivities up to 0.97 A/W. Thus, RTD-PDs pave the way towards high sensitive mid-infrared detectors that can be utilized in tunable laser absorption spectroscopy.

Infrared absorption study of hydrogen incorporation in thick nanocrystalline diamond films

International Nuclear Information System (INIS)

Tang, C.J.; Neves, A.J.; Carmo, M.C.

2005-01-01

We present an infrared (IR) optical absorbance study of hydrogen incorporation in nanocrystalline diamond films. The thick nanocrystalline diamond films were synthesized by microwave plasma-assisted chemical vapor deposition and a high growth rate about 3.0 μm/h was achieved. The morphology, phase quality, and hydrogen incorporation were assessed by means of scanning electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Large amount of hydrogen bonded to nanocrystalline diamond is clearly evidenced by the huge CH stretching band in the FTIR spectrum. The mechanism of hydrogen incorporation is discussed in light of the growth mechanism of nanocrystalline diamond. This suggests the potential of nanocrystalline diamond for IR electro-optical device applications

Nonlinear absorption and receptivity of the third order in InAs infrared region

International Nuclear Information System (INIS)

Musayev, M.A.

2005-01-01

Nonlinear absorption and receptivity of the third order and coefficient nonlinear absorption in InAs n-type with different degree of alloying was measured. Obtained score considerably exceed sense, calculated on the basis of the models describing nonlinear receptivity of electrons, situated in the nonparabolic area of conductivity. It was shown that, observable deviations withdraw; if in the calculation apply energy dissipation of electrons. Growth of the efficiency under four-wave interaction in low-energy-gap semiconductors confines nonlinear absorption of interacting waves

Optoelectronic and nonlinear optical processes in low dimensional ...

Indian Academy of Sciences (India)

Optoelectronic process; nonlinear optical process; semiconductor. Quest for ever faster and intelligent information processing technologies has sparked ..... Schematic energy level diagram for the proposed 4-level model. States other than the.

Influence of Water Activated by Far infrared Porous Ceramics on Nitrogen Absorption in the Pig Feed.

Science.gov (United States)

Meng, Junping; Liu, Jie; Liang, Jinsheng; Zhang, Hongchen; Ding, Yan

2016-04-01

Under modern and, intensive feeding livestock and poultry density has increased, and brought a deterioration of the farm environment. The livestock and their excrement generate harmful gases such as ammonia, etc. which restricted the sustainable development and improvement of production efficiency of animal husbandry. In this paper, a new kind of far infrared porous ceramics was prepared to activate, the animal drinking water. The activated water and common water were then supplied to pigs, and the fresh pig feces of experimental group and:control group were collected on a regular basis. The residual protein content in feces was tested by Kjeldahl nitrogen method to study the influence law of the porous ceramics on absorbing nitrogen element in animal feces. The results showed that compared with the control group, the protein content in the experimental group decreased on average by 39.2%. The activated drinking water was conducive to the absorption of nitrogen in pig feed. The clusters of water molecules became smaller under the action of the porous ceramics. Hence, they were easy to pass through the water protein channel on the cell membrane for speeding up the metabolism.

Monocrystalline halide perovskite nanostructures for optoelectronic applications

NARCIS (Netherlands)

Khoram, P.

2018-01-01

Halide perovskites are a promising class of materials for incorporation in optoelectronics with higher efficiency and lower cost. The solution processability of these materials provides unique opportunities for simple nanostructure fabrication. In the first half of the thesis (chapter 2 and 3) we

High temperature infrared absorption cross sections of methane near 3.4 μm in Ar and CO2 mixtures

Science.gov (United States)

Koroglu, Batikan; Neupane, Sneha; Pryor, Owen; Peale, Robert E.; Vasu, Subith S.

2018-02-01

The absorption cross-sections of CH4 at two wavelengths in the mid-IR region: λpeak = 3403.4 nm and λvalley = 3403.7 nm were measured. Data were taken using three different compositions of non-reactive gas mixtures comprising CH4/Ar/CO2 between 700 laser. Also, broadband room temperature methane cross section measurements were performed using a Fourier transform infrared spectrometer and the cascade laser to gain a better insight into the changes of the line shapes in various bath gasses (Ar, CO2, and N2). An application of the high-temperature cross-section data was demonstrated to determine the concentration of methane during oxy-methane combustion in a mixture of CO2, O2, and Ar. Current measurements will be valuable addition to the spectroscopy database for methane- an important fuel used for power generation and heating around the world.

Modelling of optoelectronic circuits based on resonant tunneling diodes

Science.gov (United States)

Rei, João. F. M.; Foot, James A.; Rodrigues, Gil C.; Figueiredo, José M. L.

2017-08-01

Resonant tunneling diodes (RTDs) are the fastest pure electronic semiconductor devices at room temperature. When integrated with optoelectronic devices they can give rise to new devices with novel functionalities due to their highly nonlinear properties and electrical gain, with potential applications in future ultra-wide-band communication systems (see e.g. EU H2020 iBROW Project). The recent coverage on these devices led to the need to have appropriated simulation tools. In this work, we present RTD based optoelectronic circuits simulation packages to provide circuit signal level analysis such as transient and frequency responses. We will present and discuss the models, and evaluate the simulation packages.

Variable Emittance Electrochromics Using Ionic Electrolytes and Low Solar Absorptance Coatings

Science.gov (United States)

Chandrasekhar, Prasanna

2011-01-01

One of the last remaining technical hurdles with variable emittance devices or skins based on conducting polymer electrochromics is the high solar absorptance of their top surfaces. This high solar absorptance causes overheating of the skin when facing the Sun in space. Existing technologies such as mechanical louvers or loop heat pipes are virtually inapplicable to micro (solar absorption to Alpha(s) of between 0.30 and 0.46. Coupled with the emittance properties of the variable emittance skins, this lowers the surface temperature of the skins facing the Sun to between 30 and 60 C, which is much lower than previous results of 100 C, and is well within acceptable satellite operations ranges. The performance of this technology is better than that of current new technologies such as microelectromechanical systems (MEMS), electrostatics, and electrophoretics, especially in applications involving micro and nano spacecraft. The coatings are deposited inside a high vacuum, layering multiple coatings onto the top surfaces of variable emittance skins. They are completely transparent in the entire relevant infrared region (about 2 to 45 microns), but highly reflective in the visible-NIR (near infrared) region of relevance to solar absorptance.

Photodetector of ultraviolet radiation

International Nuclear Information System (INIS)

Dorogan, V.; Branzari, V.; Vieru, T.; Manole, M.; Canter, V.

2000-01-01

The invention relates to photodetectors on base of semiconductors of ultraviolet radiation and may be used in optoelectronic system for determining the intensity and the dose of ultraviolet radiation emitted by the Sun or other sources. Summary of the invention consists in the fact that in the photodetector of ultraviolet radiation the superficial potential barrier is divided into two identical elements, electrically isolated each of the other, one of them being covered with a layer of transparent material for visible and infrared radiation and absorption the ultra violet radiation. The technical result consists in mutual compensation of visible and infrared components of the radiation spectrum

Generation of pulsed far-infrared radiation and its application for far-infrared time-resolved spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Kondo, Yasuhiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

1996-07-01

So-called time-resolved spectroscopy technique has been used from old time as the means for studying the dynamic optical property, light-induced reaction and so on of matters. As an example, there is the method called pump and probe, and here, the wavelength of this probe light is the problem. If the object energy region is limited to about 0.1 eV, fast time-resolved spectroscopy is feasible relatively easily. However, energy region is extended to low energy region, the light source which is available as the pulsed probe light having sufficient intensity is limited. In this paper, the attempt of time-resolved spectroscopy utilizing coherent radiation, which has ended in failure, and the laser pulse-induced far-infrared radiation which can be utilized as new far-infrared probe light are reported. The reason why far-infrared radiation is used is explained. The attempt of time-resolved spectroscopy using NaCl crystals is reported on the equipment, the method of measuring absorption spectra and the results. Laser pulse-induced far-infrared radiation and the method of generating it are described. The multi-channel detector for far-infrared radiation which was made for trial is shown. (K.I.)

Basic opto-electronics on silicon for sensor applications

NARCIS (Netherlands)

Joppe, J.L.; Bekman, H.H.P.Th.; de Krijger, A.J.T.; Albers, H.; Chalmers, J.; Chalmers, J.D.; Holleman, J.; Ikkink, T.J.; Ikkink, T.; van Kranenburg, H.; Zhou, M.-J.; Zhou, Ming-Jiang; Lambeck, Paul

1994-01-01

A general platform for integrated opto-electronic sensor systems on silicon is proposed. The system is based on a hybridly integrated semiconductor laser, ZnO optical waveguides and monolithic photodiodes and electronic circuiry.

77 FR 65713 - Certain Optoelectronic Devices for Fiber Optic Communications, Components Thereof, and Products...

Science.gov (United States)

2012-10-30

... Fiber Optic Communications, Components Thereof, and Products Containing the Same; Notice of Institution... certain optoelectronic devices for fiber optic communications, components thereof, and products containing... optoelectronic devices for fiber optic communications, components thereof, and products containing the same that...

Tuning the optical response in carbon doped boron nitride nanodots

KAUST Repository

Mokkath, Junais Habeeb

2014-09-04

Time dependent density functional theory and the hybrid B3LYP functional are used to investigate the structural and optical properties of pristine and carbon doped hexagonal boron nitride nanodots. In agreement with recent experiments, the embedded carbon atoms are found to favor nucleation. Our results demonstrate that carbon clusters of different shapes promote an early onset of absorption by generating in-gap states. The nanodots are interesting for opto-electronics due to their tunable optical response in a wide energy window. We identify cluster sizes and shapes with optimal conversion efficiency for solar radiation and a wide absorption range form infrared to ultraviolet. This journal is

Nanoantennas for visible and infrared radiation

International Nuclear Information System (INIS)

Biagioni, Paolo; Huang, Jer-Shing; Hecht, Bert

2012-01-01

Nanoantennas for visible and infrared radiation can strongly enhance the interaction of light with nanoscale matter by their ability to efficiently link propagating and spatially localized optical fields. This ability unlocks an enormous potential for applications ranging from nanoscale optical microscopy and spectroscopy over solar energy conversion, integrated optical nanocircuitry, opto-electronics and density-of-states engineering to ultra-sensing as well as enhancement of optical nonlinearities. Here we review the current understanding of metallic optical antennas based on the background of both well-developed radiowave antenna engineering and plasmonics. In particular, we discuss the role of plasmonic resonances on the performance of nanoantennas and address the influence of geometrical parameters imposed by nanofabrication. Finally, we give a brief account of the current status of the field and the major established and emerging lines of investigation in this vivid area of research.

Nanoantennas for visible and infrared radiation

Energy Technology Data Exchange (ETDEWEB)

Biagioni, Paolo [CNISM-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Huang, Jer-Shing [Department of Chemistry and Frontier Research Center on Fundamental and Applied Science of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Hecht, Bert [Nano-Optics and Biophotonics Group, Department of Experimental Physics 5, Wilhelm Conrad Roentgen Research Center for Complex Material Systems (RCCM), Physics Institute, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany)

2012-02-15

Nanoantennas for visible and infrared radiation can strongly enhance the interaction of light with nanoscale matter by their ability to efficiently link propagating and spatially localized optical fields. This ability unlocks an enormous potential for applications ranging from nanoscale optical microscopy and spectroscopy over solar energy conversion, integrated optical nanocircuitry, opto-electronics and density-of-states engineering to ultra-sensing as well as enhancement of optical nonlinearities. Here we review the current understanding of metallic optical antennas based on the background of both well-developed radiowave antenna engineering and plasmonics. In particular, we discuss the role of plasmonic resonances on the performance of nanoantennas and address the influence of geometrical parameters imposed by nanofabrication. Finally, we give a brief account of the current status of the field and the major established and emerging lines of investigation in this vivid area of research.

Feasibility of infrared analysis of iron in zircon

International Nuclear Information System (INIS)

Heard, I. Jr.

1980-05-01

A feasibility study has concluded that quantitative infrared analysis can be employed to determine the concentration of iron in zircon. The spectral transmission curves have shown that the iron absorption band is located at 1.15 microns. These curves also revealed a second absorption band at 1.49 microns. The source of this second peak is not known; but it exhibits some features which suggest its dependance on natural α-recoil damage. 23 references, 14 figures, 2 tables

Near-infrared water vapour self-continuum at close to room temperature

International Nuclear Information System (INIS)

Ptashnik, I.V.; Petrova, T.M.; Ponomarev, Yu.N.; Shine, K.P.; Solodov, A.A.; Solodov, A.M.

2013-01-01

The gaseous absorption of solar radiation within near-infrared atmospheric windows in the Earth's atmosphere is dominated by the water vapour continuum. Recent measurements by Baranov et al. (2011) [17] in 2500 cm −1 (4 μm) window and by Ptashnik et al. (2011) [18] in a few near-infrared windows revealed that the self-continuum absorption is typically an order of magnitude stronger than given by the MT C KD continuum model prior to version 2.5. Most of these measurements, however, were made at elevated temperatures, which makes their application to atmospheric conditions difficult. Here we report new laboratory measurements of the self-continuum absorption at 289 and 318 K in the near-infrared spectral region 1300–8000 cm −1 , using a multipass 30 m base cell with total optical path 612 m. Our results confirm the main conclusions of the previous measurements both within bands and in windows. Of particular note is that we present what we believe to be the first near-room temperature measurement using Fourier Transform Spectrometry of the self-continuum in the 6200 cm −1 (1.6 μm) window, which provides tentative evidence that, at such temperatures, the water vapour continuum absorption may be as strong as it is in 2.1 μm and 4 μm windows and up to 2 orders of magnitude stronger than the MT C KD-2.5 continuum. We note that alternative methods of measuring the continuum in this window have yielded widely differing assessment of its strength, which emphasises the need for further measurements. -- Highlights: ► New lab measurements of the near-infrared water vapour self-continuum absorption. ► First room-temperature data on the self-continuum in the 1.6 μm window. ► In the 1.6 μm window the new data exceed MT C KD-2.5 model by 2 orders of magnitude

Peculiarities of infrared absorption in V/sub 3/Si

Energy Technology Data Exchange (ETDEWEB)

Nomerovannaya, L V; Marchenko, V A [AN SSSR, Sverdlovsk. Inst. Fiziki Metallov

1985-01-01

Using the polarimetry method, optical properties of V/sub 3/Si monocrystals have been studied in the 0.07... 500 eV (lambda = 17...0.25 ..mu..m) spectrum range at room temperature. An anomalous frequency dependence of the optical conductivity, sigma(..omega..), in the infrared region of spectrum at the energies E < 0.1 eV is detected which is manifested in the increase of sigma(..omega..) with the frequency ..omega... Possible reasons of such frequency dependence are discussed.

Terahertz optoelectronics with surface plasmon polariton diode.

Science.gov (United States)

Vinnakota, Raj K; Genov, Dentcho A

2014-05-09

The field of plasmonics has experience a renaissance in recent years by providing a large variety of new physical effects and applications. Surface plasmon polaritons, i.e. the collective electron oscillations at the interface of a metal/semiconductor and a dielectric, may bridge the gap between electronic and photonic devices, provided a fast switching mechanism is identified. Here, we demonstrate a surface plasmon-polariton diode (SPPD) an optoelectronic switch that can operate at exceedingly large signal modulation rates. The SPPD uses heavily doped p-n junction where surface plasmon polaritons propagate at the interface between n and p-type GaAs and can be switched by an external voltage. The devices can operate at transmission modulation higher than 98% and depending on the doping and applied voltage can achieve switching rates of up to 1 THz. The proposed switch is compatible with the current semiconductor fabrication techniques and could lead to nanoscale semiconductor-based optoelectronics.

GaAs photovoltaics and optoelectronics using releasable multilayer epitaxial assemblies.

Science.gov (United States)

Yoon, Jongseung; Jo, Sungjin; Chun, Ik Su; Jung, Inhwa; Kim, Hoon-Sik; Meitl, Matthew; Menard, Etienne; Li, Xiuling; Coleman, James J; Paik, Ungyu; Rogers, John A

2010-05-20

Compound semiconductors like gallium arsenide (GaAs) provide advantages over silicon for many applications, owing to their direct bandgaps and high electron mobilities. Examples range from efficient photovoltaic devices to radio-frequency electronics and most forms of optoelectronics. However, growing large, high quality wafers of these materials, and intimately integrating them on silicon or amorphous substrates (such as glass or plastic) is expensive, which restricts their use. Here we describe materials and fabrication concepts that address many of these challenges, through the use of films of GaAs or AlGaAs grown in thick, multilayer epitaxial assemblies, then separated from each other and distributed on foreign substrates by printing. This method yields large quantities of high quality semiconductor material capable of device integration in large area formats, in a manner that also allows the wafer to be reused for additional growths. We demonstrate some capabilities of this approach with three different applications: GaAs-based metal semiconductor field effect transistors and logic gates on plates of glass, near-infrared imaging devices on wafers of silicon, and photovoltaic modules on sheets of plastic. These results illustrate the implementation of compound semiconductors such as GaAs in applications whose cost structures, formats, area coverages or modes of use are incompatible with conventional growth or integration strategies.

Optoelectronic properties of higher acenes, their BN analogue and substituted derivatives

International Nuclear Information System (INIS)

Armaković, Stevan; Armaković, Sanja J.; Holodkov, Vladimir; Pelemiš, Svetlana

2016-01-01

We have investigated optoelectronic properties of higher acenes: pentacene, hexacene, heptacene, octacene, nonacene, decacene and their boron-nitride (BN) analogues, within the framework of density functional theory (DFT). We have also investigated the optoelectronic properties of acenes modified by BN substitution. Calculated optoelectronic properties encompasses: oxidation and reduction potentials, electron and hole reorganization energies and energy difference between excited first singlet and triplet states ΔE(S_1−T_1). Oxidation and reduction potentials indicate significantly better stability of BN analogues, comparing with their all-carbon relatives. Although higher acenes possess lower electron and hole reorganization energies, with both best values much lower than 0.1 eV, their BN analogues also have competitive values of reorganization energies, especially for holes for which reorganization energy is also lower than 0.1 eV. On the other hand ΔE(S_1−T_1) is much better for BN analogues, having values that indicate that BN analogues are possible applicable for thermally activated delayed fluorescence. - Highlights: • Optoelectronic properties of structures based on higher acenes have been investigated. • Oxidation and reduction potentials together with reorganization energies are calculated. • TADF is analyzed through calculation of ΔE(S_1−T_1), which is much better for BN analogues. • Reorganization energies of acenes improve with the increase of number of benzene rings.

Enhancing electronic and optoelectronic performances of tungsten diselenide by plasma treatment.

Science.gov (United States)

Xie, Yuan; Wu, Enxiu; Hu, Ruixue; Qian, Shuangbei; Feng, Zhihong; Chen, Xuejiao; Zhang, Hao; Xu, Linyan; Hu, Xiaodong; Liu, Jing; Zhang, Daihua

2018-06-21

Transition metal dichalcogenides (TMDCs) have recently become spotlighted as nanomaterials for future electronic and optoelectronic devices. In this work, we develop an effective approach to enhance the electronic and optoelectronic performances of WSe2-based devices by N2O plasma treatment. The hole mobility and sheet density increase by 2 and 5 orders of magnitude, reaching 110 cm2 V-1 s-1 and 2.2 × 1012 cm-2, respectively, after the treatment. At the same time, the contact resistance (Rc) between WSe2 and its metal electrode drop by 5 orders of magnitude from 1.0 GΩ μm to 28.4 kΩ μm. The WSe2 photoconductor exhibits superior performance with high responsivity (1.5 × 105 A W-1), short response time (106). We have also built a lateral p-n junction on a single piece of WSe2 flake by selective plasma exposure. The junction reaches an exceedingly high rectifying ratio of 106, an excellent photoresponsivity of 2.49 A W-1 and a fast response of 8 ms. The enhanced optoelectronic performance is attributed to band-engineering through the N2O plasma treatment, which can potentially serve as an effective and versatile approach for device engineering and optimization in a wide range of electronic and optoelectronic devices based on 2D materials.

Optoelectronic properties of XIn2S4 (X = Cd, Mg) thiospinels through highly accurate all-electron FP-LAPW method coupled with modified approximations

International Nuclear Information System (INIS)

Yousaf, Masood; Dalhatu, S.A.; Murtaza, G.; Khenata, R.; Sajjad, M.; Musa, A.; Rahnamaye Aliabad, H.A.; Saeed, M.A.

2015-01-01

Highlights: • Highly accurate all-electron FP-LAPW+lo method is used. • New physical parameters are reported, important for the fabrication of optoelectronic devices. • A comparative study that involves FP-LAPW+lo method and modified approximations. • Computed band gap values have good agreement with the experimental values. • Optoelectronic results of fundamental importance can be utilized for the fabrication of devices. - Abstract: We report the structural, electronic and optical properties of the thiospinels XIn 2 S 4 (X = Cd, Mg), using highly accurate all-electron full potential linearized augmented plane wave plus local orbital method. In order to calculate the exchange and correlation energies, the method is coupled with modified techniques such as GGA+U and mBJ-GGA, which yield improved results as compared to the previous studies. GGA+SOC approximation is also used for the first time on these compounds to examine the spin orbit coupling effect on the band structure. From the analysis of the structural parameters, robust character is predicted for both materials. Energy band structures profiles are fairly the same for GGA, GGA+SOC, GGA+U and mBJ-GGA, confirming the indirect and direct band gap nature of CdIn 2 S 4 and MgIn 2 S 4 materials, respectively. We report the trend of band gap results as: (mBJ-GGA) > (GGA+U) > (GGA) > (GGA+SOC). Localized regions appearing in the valence bands for CdIn 2 S 4 tend to split up nearly by ≈1 eV in the case of GGA+SOC. Many new physical parameters are reported that can be important for the fabrication of optoelectronic devices. Optical spectra namely, dielectric function (DF), refractive index n(ω), extinction coefficient k(ω), reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω) and electron loss function are discussed. Optical’s absorption edge is noted to be 1.401 and 1.782 for CdIn 2 S 4 and MgIn 2 S 4 , respectively. The prominent peaks in the electron energy spectrum

A Simple, Student-Built Spectrometer to Explore Infrared Radiation and Greenhouse Gases

Science.gov (United States)

Bruce, Mitchell R. M.; Wilson, Tiffany A.; Bruce, Alice E.; Bessey, S. Max; Flood, Virginia J.

2016-01-01

In this experiment, students build a spectrometer to explore infrared radiation and greenhouse gases in an inquiry-based investigation to introduce climate science in a general chemistry lab course. The lab is based on the exploration of the thermal effects of molecular absorption of infrared radiation by greenhouse and non-greenhouse gases. A…

Far infrared polarimetry of W51A and M42

Energy Technology Data Exchange (ETDEWEB)

Cudlip, W; Furniss, I; King, K J; Jennings, R E [University Coll., London (UK). Dept. of Physics and Astronomy

1982-09-01

A far infrared polarimeter has been designed for use with a balloon-borne telescope. It uses a rapidly rotating wire grid polarizer with the chopping secondary mirror of the telescope synchronized to the rate of rotation. Observations of M42 using this system show a far infrared polarization of 2.2 +- 0.4 per cent, nearly orthogonal to the near infrared polarization which is usually attributed to dust absorption. Observations of W51A show a much smaller value of the polarization of 0.8 +- 0.5 per cent.

MID-INFRARED PROPERTIES OF OH MEGAMASER HOST GALAXIES. I. SPITZER IRS LOW- AND HIGH-RESOLUTION SPECTROSCOPY

International Nuclear Information System (INIS)

Willett, Kyle W.; Darling, Jeremy; Spoon, Henrik W. W.; Charmandaris, Vassilis; Armus, Lee

2011-01-01

We present mid-infrared spectra and photometry from the Infrared Spectrograph on the Spitzer Space Telescope for 51 OH megamasers (OHMs), along with 15 galaxies confirmed to have no megamaser emission above L OH = 10 2.3 L sun . The majority of galaxies display moderate-to-deep 9.7 μm amorphous silicate absorption, with OHM galaxies showing stronger average absorption and steeper 20-30 μm continuum emission than non-masing galaxies. Emission from multiple polycyclic aromatic hydrocarbons (PAHs), especially at 6.2, 7.7, and 11.3 μm, is detected in almost all systems. Fine-structure atomic emission (including [Ne II], [Ne III], [S III], and [S IV]) and multiple H 2 rotational transitions are observed in more than 90% of the sample. A subset of galaxies show emission from rarer atomic lines, such as [Ne V], [O IV], and [Fe II]. Fifty percent of the OHMs show absorption from water ice and hydrogenated amorphous carbon grains, while absorption features from CO 2 , HCN, C 2 H 2 , and crystalline silicates are also seen in several OHMs. Column densities of OH derived from 34.6 μm OH absorption are similar to those derived from 1667 MHz OH absorption in non-masing galaxies, indicating that the abundance of masing molecules is similar for both samples. This data paper presents full mid-infrared spectra for each galaxy, along with measurements of line fluxes and equivalent widths, absorption feature depths, and spectral indices.

Mid-Infrared Properties of OH Megamaser Host Galaxies. I. Spitzer IRS Low- and High-Resolution Spectroscopy

Science.gov (United States)

Willett, Kyle W.; Darling, Jeremy; Spoon, Henrik W. W.; Charmandaris, Vassilis; Armus, Lee

2011-03-01

We present mid-infrared spectra and photometry from the Infrared Spectrograph on the Spitzer Space Telescope for 51 OH megamasers (OHMs), along with 15 galaxies confirmed to have no megamaser emission above L OH = 102.3 L sun. The majority of galaxies display moderate-to-deep 9.7 μm amorphous silicate absorption, with OHM galaxies showing stronger average absorption and steeper 20-30 μm continuum emission than non-masing galaxies. Emission from multiple polycyclic aromatic hydrocarbons (PAHs), especially at 6.2, 7.7, and 11.3 μm, is detected in almost all systems. Fine-structure atomic emission (including [Ne II], [Ne III], [S III], and [S IV]) and multiple H2 rotational transitions are observed in more than 90% of the sample. A subset of galaxies show emission from rarer atomic lines, such as [Ne V], [O IV], and [Fe II]. Fifty percent of the OHMs show absorption from water ice and hydrogenated amorphous carbon grains, while absorption features from CO2, HCN, C2H2, and crystalline silicates are also seen in several OHMs. Column densities of OH derived from 34.6 μm OH absorption are similar to those derived from 1667 MHz OH absorption in non-masing galaxies, indicating that the abundance of masing molecules is similar for both samples. This data paper presents full mid-infrared spectra for each galaxy, along with measurements of line fluxes and equivalent widths, absorption feature depths, and spectral indices.

A mid-infrared laser absorption sensor for carbon monoxide and temperature measurements

Science.gov (United States)

Vanderover, Jeremy

A mid-infrared (mid-IR) absorption sensor based on quantum cascade laser (QCL) technology has been developed and demonstrated for high-temperature thermometry and carbon monoxide (CO) measurements in combustion environments. The sensor probes the high-intensity fundamental CO ro-vibrational band at 4.6 mum enabling sensitive measurement of CO and temperature at kHz acquisition rates. Because the sensor operates in the mid-IR CO fundamental band it is several orders of magnitude more sensitive than most of the previously developed CO combustion sensors which utilized absorption in the near-IR overtone bands and mature traditional telecommunications-based diode lasers. The sensor has been demonstrated and validated under operation in both scanned-wavelength absorption and wavelength-modulation spectroscopy (WMS) modes in room-temperature gas cell and high-temperature shock tube experiments with known and specified gas conditions. The sensor has also been demonstrated for CO and temperature measurements in an atmospheric premixed ethylene/air McKenna burner flat flame for a range of equivalence ratios (phi = 0.7-1.4). Demonstration of the sensor under scanned-wavelength direct absorption operation was performed in a room-temperature gas cell (297 K and 0.001-1 atm) allowing validation of the line strengths and line shapes predicted by the HITRAN 2004 spectroscopic database. Application of the sensor in scanned-wavelength mode, at 1-2 kHz acquisition bandwidths, to specified high-temperature shock-heated gases (950-3400 K, 1 atm) provided validation of the sensor for measurements under the high-temperature conditions found in combustion devices. The scanned-wavelength shock tube measurements yielded temperature determinations that deviated by only +/-1.2% (1-sigma deviation) with the reflected shock temperatures and CO mole fraction determinations that deviated by that specified CO mole fraction by only +/-1.5% (1-sigma deviation). These deviations are in fact smaller

Use of absorption spectroscopy for refined petroleum product discrimination

Science.gov (United States)

Short, Michael

1991-07-01

On-line discrimination between arbitrary petroleum products is necessary for optimal control of petroleum refinery and pipeline operation and process control involving petroleum distillates. There are a number of techniques by which petroleum products can be distinguished from one another. Among these, optical measurements offer fast, non-intrusive, real-time characterization. The application examined here involves optically monitoring the interface between dissimilar batches of fluids in a gasoline pipeline. After examination of near- infrared and mid-infrared absorption spectroscopy and Raman spectroscopy, Fourier transform mid-infrared (FTIR) spectroscopy was chosen as the best candidate for implementation. On- line FTIR data is presented, verifying the applicability of the technique for batch interface detection.

Crystalline Molybdenum Oxide Thin-Films for Application as Interfacial Layers in Optoelectronic Devices

DEFF Research Database (Denmark)

Fernandes Cauduro, André Luis; dos Reis, Roberto; Chen, Gong

2017-01-01

The ability to control the interfacial properties in metal-oxide thin films through surface defect engineering is vital to fine-tune their optoelectronic properties and thus their integration in novel optoelectronic devices. This is exemplified in photovoltaic devices based on organic, inorganic...... or hybrid technologies, where precise control of the charge transport properties through the interfacial layer is highly important for improving device performance. In this work, we study the effects of in situ annealing in nearly stoichiometric MoOx (x ∼ 3.0) thin-films deposited by reactive sputtering. We...... with structural characterizations, this work addresses a novel method for tuning, and correlating, the optoelectronic properties and microstructure of device-relevant MoOx layers....

Fringes in FTIR spectroscopy revisited: understanding and modelling fringes in infrared spectroscopy of thin films.

Science.gov (United States)

Konevskikh, Tatiana; Ponossov, Arkadi; Blümel, Reinhold; Lukacs, Rozalia; Kohler, Achim

2015-06-21

The appearance of fringes in the infrared spectroscopy of thin films seriously hinders the interpretation of chemical bands because fringes change the relative peak heights of chemical spectral bands. Thus, for the correct interpretation of chemical absorption bands, physical properties need to be separated from chemical characteristics. In the paper at hand we revisit the theory of the scattering of infrared radiation at thin absorbing films. Although, in general, scattering and absorption are connected by a complex refractive index, we show that for the scattering of infrared radiation at thin biological films, fringes and chemical absorbance can in good approximation be treated as additive. We further introduce a model-based pre-processing technique for separating fringes from chemical absorbance by extended multiplicative signal correction (EMSC). The technique is validated by simulated and experimental FTIR spectra. It is further shown that EMSC, as opposed to other suggested filtering methods for the removal of fringes, does not remove information related to chemical absorption.

The influence of local electric fields on photoinduced absorption in dye-sensitized solar cells.

Science.gov (United States)

Cappel, Ute B; Feldt, Sandra M; Schöneboom, Jan; Hagfeldt, Anders; Boschloo, Gerrit

2010-07-07

The dye-sensitized solar cell (DSC) challenges conventional photovoltaics with its potential for low-cost production and its flexibility in terms of color and design. Transient absorption spectroscopy is widely used to unravel the working mechanism of DSCs. A surprising, unexplained feature observed in these studies is an apparent bleach of the ground-state absorption of the dye, under conditions where the dye is in the ground state. Here, we demonstrate that this feature can be attributed to a change of the local electric field affecting the absorption spectrum of the dye, an effect related to the Stark effect first reported in 1913. We present a method for measuring the effect of an externally applied electric field on the absorption of dye monolayers adsorbed on flat TiO(2) substrates. The measured signal has the shape of the first derivative of the absorption spectra of the dyes and reverses sign along with the reversion of the direction of the change in dipole moment upon excitation relative to the TiO(2) surface. A very similar signal is observed in photoinduced absorption spectra of dye-sensitized TiO(2) electrodes under solar cell conditions, demonstrating that the electric field across the dye molecules changes upon illumination. This result has important implications for the analysis of transient absorption spectra of DSCs and other molecular optoelectronic devices and challenges the interpretation of many previously published results.

Sintering effect on the optoelectronic characteristics of HgSe nanoparticle films on plastic substrates

International Nuclear Information System (INIS)

Byun, Kwangsub; Cho, Kyoungah; Kim, Sangsig

2010-01-01

The optoelectronic characteristics of HgSe nanoparticle films spin-coated on flexible plastic substrates are investigated under the illumination of 1.3 μm wavelength light. The sintering process improves the optoelectronic characteristics of the HgSe nanoparticle films. The photocurrent of the sintered HgSe nanoparticle films under the illumination of 1.3 μm wavelength light is approximately 20 times larger in magnitude than that of the non-sintered films in air at room temperature. Moreover, the endurance of the flexible optoelectronic device investigated by the continuous substrate bending test reveals that the photocurrent efficiency changes negligibly up to 250 cycles.

Effects of laser radiation parameters of the infrared multiphoton dissociation of protonated trichloroethylene

International Nuclear Information System (INIS)

Ungureanu, C.; Almasan, V.

1994-01-01

The favorable properties of the infrared multiphoton absorption and dissociation of trichloroethylene-H, (C 2 HCl 3 ), by TEA-CO 2 laser radiation and rapid isotopic exchange between this molecule and water, indicate that it can be a promising further candidate for the final enrichment of heavy water (> 98% D 2 O), by laser method. We present the results obtained in the isotopic selectivity of multiphoton absorption measurements and in the study of the pulse energy and frequency laser radiation influence on the infrared multiphoton dissociation of C 2 HCl 3 in isotopic mixture with C 2 DCl 3 . (Author)

Infrared thermal annealing device

International Nuclear Information System (INIS)

Gladys, M.J.; Clarke, I.; O'Connor, D.J.

2003-01-01

A device for annealing samples within an ultrahigh vacuum (UHV) scanning tunneling microscopy system was designed, constructed, and tested. The device is based on illuminating the sample with infrared radiation from outside the UHV chamber with a tungsten projector bulb. The apparatus uses an elliptical mirror to focus the beam through a sapphire viewport for low absorption. Experiments were conducted on clean Pd(100) and annealing temperatures in excess of 1000 K were easily reached

Enhancement of absorption and color contrast in ultra-thin highly absorbing optical coatings

Science.gov (United States)

Kats, Mikhail A.; Byrnes, Steven J.; Blanchard, Romain; Kolle, Mathias; Genevet, Patrice; Aizenberg, Joanna; Capasso, Federico

2013-09-01

Recently a new class of optical interference coatings was introduced which comprises ultra-thin, highly absorbing dielectric layers on metal substrates. We show that these lossy coatings can be augmented by an additional transparent subwavelength layer. We fabricated a sample comprising a gold substrate, an ultra-thin film of germanium with a thickness gradient, and several alumina films. The experimental reflectivity spectra showed that the additional alumina layer increases the color range that can be obtained, in agreement with calculations. More generally, this transparent layer can be used to enhance optical absorption, protect against erosion, or as a transparent electrode for optoelectronic devices.

High-temperature measurements of methane and acetylene using quantum cascade laser absorption near 8μm

KAUST Repository

Sajid, M.B.; Javed, Tamour; Farooq, Aamir

2015-01-01

The mid-infrared wavelength region near 8 mu m contains absorption bands of several molecules such as water vapor, hydrogen peroxide, nitrous oxide, methane and acetylene. A new laser absorption sensor based on the v(4) band of methane and the v(4

Hydrogen, oxygen and hydroxyl on porous silicon surface: A joint density-functional perturbation theory and infrared spectroscopy approach

International Nuclear Information System (INIS)

Alfaro, Pedro; Palavicini, Alessio; Wang, Chumin

2014-01-01

Based on the density functional perturbation theory (DFPT), infrared absorption spectra of porous silicon are calculated by using an ordered pore model, in which columns of silicon atoms are removed along the [001] direction and dangling bonds are initially saturated with hydrogen atoms. When these atoms on the pore surface are gradually replaced by oxygen ones, the ab-initio infrared absorption spectra reveal oxygen, hydroxyl, and coupled hydrogen–oxygen vibrational modes. In a parallel way, freestanding porous silicon samples were prepared by using electrochemical etching and they were further thermally oxidized in a dry oxygen ambient. Fourier transform infrared spectroscopy was used to investigate the surface modifications caused by oxygen adsorption. In particular, the predicted hydroxyl and oxygen bound to the silicon pore surface are confirmed. Finally, a global analysis of measured transmittance spectra has been performed by means of a combined DFPT and thin-film optics approach. - Highlights: • The density functional perturbation theory is used to study infrared absorption. • An ordered pore model is used to investigate the oxidation in porous silicon (PSi). • Infrared transmittance spectra of oxidized PSi freestanding samples are measured

Absorption spectroscopic studies of carbon dioxide conversion in a low pressure glow discharge using tunable infrared diode lasers

International Nuclear Information System (INIS)

Hempel, F; Roepcke, J; Miethke, F; Wagner, H-E

2002-01-01

The time and spatial dependence of the chemical conversion of CO 2 to CO were studied in a closed glow discharge reactor (p = 50 Pa, I = 2-30 mA) consisting of a small plasma zone and an extended stationary afterglow. Tunable infrared diode laser absorption spectroscopy has been applied to determine the absolute ground state concentrations of CO and CO 2 . After a certain discharge time an equilibrium of the concentrations of both species could be observed. The spatial dependence of the equilibrium CO concentration in the afterglow was found to be varying less than 10%. The feed gas was converted to CO more predominantly between 43% and 60% with increasing discharge current, forming so-called quasi-equilibrium states of the stable reaction products. The formation time of the stable gas composition also decreased with the current. For currents higher than 10 mA the conversion rate of CO 2 to CO was estimated to be 1.2x10 13 molecules J -1 . Based on the experimental results, a plasma chemical modelling has been established

Advanced infrared optically black baffle materials

International Nuclear Information System (INIS)

Seals, R.D.; Egert, C.M.; Allred, D.D.

1990-01-01

Infrared optically black baffle surfaces are an essential component of many advanced optical systems. All internal surfaces in advanced infrared optical sensors that require stray light management to achieve resolution are of primary concern in baffle design. Current industrial materials need improvements to meet advanced optical sensor systems requirements for optical, survivability, and endurability. Baffles are required to survive and operate in potentially severe environments. Robust diffuse-absorptive black surfaces, which are thermally and mechanically stable to threats of x-ray, launch, and in-flight maneuver conditions, with specific densities to allow an acceptable weight load, handleable during assembly, cleanable, and adaptive to affordable manufacturing, are required as optical baffle materials. In this paper an overview of recently developed advanced infrared optical baffle materials, requirements, manufacturing strategies, and the Optics MODIL (Manufacturing Operations Development and Integration Laboratory) Advanced Baffle Program are discussed

Graphene-based mid-infrared room-temperature pyroelectric bolometers with ultrahigh temperature coefficient of resistance.

Science.gov (United States)

Sassi, U; Parret, R; Nanot, S; Bruna, M; Borini, S; De Fazio, D; Zhao, Z; Lidorikis, E; Koppens, F H L; Ferrari, A C; Colli, A

2017-01-31

There is a growing number of applications demanding highly sensitive photodetectors in the mid-infrared. Thermal photodetectors, such as bolometers, have emerged as the technology of choice, because they do not need cooling. The performance of a bolometer is linked to its temperature coefficient of resistance (TCR, ∼2-4% K -1 for state-of-the-art materials). Graphene is ideally suited for optoelectronic applications, with a variety of reported photodetectors ranging from visible to THz frequencies. For the mid-infrared, graphene-based detectors with TCRs ∼4-11% K -1 have been demonstrated. Here we present an uncooled, mid-infrared photodetector, where the pyroelectric response of a LiNbO 3 crystal is transduced with high gain (up to 200) into resistivity modulation for graphene. This is achieved by fabricating a floating metallic structure that concentrates the pyroelectric charge on the top-gate capacitor of the graphene channel, leading to TCRs up to 900% K -1 , and the ability to resolve temperature variations down to 15 μK.

Enhancing the Responsivity of Uncooled Infrared Detectors Using Plasmonics for High-Performance Infrared Spectroscopy

Directory of Open Access Journals (Sweden)

Amr Shebl Ahmed

2017-04-01

Full Text Available A lead zirconate titanate (PZT;Pb(Zr0.52Ti0.48O3 layer embedded infrared (IR detector decorated with wavelength-selective plasmonic crystals has been investigated for high-performance non-dispersive infrared (NDIR spectroscopy. A plasmonic IR detector with an enhanced IR absorption band has been designed based on numerical simulations, fabricated by conventional microfabrication techniques, and characterized with a broadly tunable quantum cascade laser. The enhanced responsivity of the plasmonic IR detector at specific wavelength band has improved the performance of NDIR spectroscopy and pushed the limit of detection (LOD by an order of magnitude. In this paper, a 13-fold enhancement in the LOD of a methane gas sensing using NDIR spectroscopy is demonstrated with the plasmonic IR detector.

Optoelectronic Characterization by Advanced Ab-Initio Methods of Novel Photovoltaic Intermediate Band Materials = Caracterización optoelectrónica por métodos ab-initio avanzados de nuevos materiales fotovoltaicos de banda intermedia

OpenAIRE

Aguilera Bonet, Irene

2011-01-01

Intermediate-band materials represent nowadays one of the most promising proposals in the quest for more efficient, lower-cost solar cells. In this thesis we present a deep study of transition-metal substituted semiconductors based on their optoelectronic properties. These materials were proposed as high efficiency photovoltaic absorbers for intermediate-band solar cells for showing a partiallyfilled band placed inside the band gap of the parent semiconductor which enables the absorption of p...

Optoelectronic properties of higher acenes, their BN analogue and substituted derivatives

Energy Technology Data Exchange (ETDEWEB)

Armaković, Stevan, E-mail: stevan.armakovic@df.uns.ac.rs [University of Novi Sad, Faculty of Sciences, Department of Physics, Trg Dositeja Obradovića 4, 21000, Novi Sad (Serbia); Armaković, Sanja J. [University of Novi Sad, Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg Dositeja Obradovića 3, 21000, Novi Sad (Serbia); Holodkov, Vladimir [Educons University, Faculty of Sport and Tourism - TIMS, Radnička 30a, 21000, Novi Sad (Serbia); Pelemiš, Svetlana [University of East Sarajevo, Faculty of Technology, Karakaj bb, 75400, Zvornik, Republic of Srpska, Bosnia and Herzegovina (Bosnia and Herzegovina)

2016-02-15

We have investigated optoelectronic properties of higher acenes: pentacene, hexacene, heptacene, octacene, nonacene, decacene and their boron-nitride (BN) analogues, within the framework of density functional theory (DFT). We have also investigated the optoelectronic properties of acenes modified by BN substitution. Calculated optoelectronic properties encompasses: oxidation and reduction potentials, electron and hole reorganization energies and energy difference between excited first singlet and triplet states ΔE(S{sub 1}−T{sub 1}). Oxidation and reduction potentials indicate significantly better stability of BN analogues, comparing with their all-carbon relatives. Although higher acenes possess lower electron and hole reorganization energies, with both best values much lower than 0.1 eV, their BN analogues also have competitive values of reorganization energies, especially for holes for which reorganization energy is also lower than 0.1 eV. On the other hand ΔE(S{sub 1}−T{sub 1}) is much better for BN analogues, having values that indicate that BN analogues are possible applicable for thermally activated delayed fluorescence. - Highlights: • Optoelectronic properties of structures based on higher acenes have been investigated. • Oxidation and reduction potentials together with reorganization energies are calculated. • TADF is analyzed through calculation of ΔE(S{sub 1}−T{sub 1}), which is much better for BN analogues. • Reorganization energies of acenes improve with the increase of number of benzene rings.

Transport Measurements and Synchrotron-Based X-Ray Absorption Spectroscopy of Iron Silicon Germanide Grown by Molecular Beam Epitaxy

Science.gov (United States)

Elmarhoumi, Nader; Cottier, Ryan; Merchan, Greg; Roy, Amitava; Lohn, Chris; Geisler, Heike; Ventrice, Carl, Jr.; Golding, Terry

2009-03-01

Some of the iron-based metal silicide and germanide phases have been predicted to be direct band gap semiconductors. Therefore, they show promise for use as optoelectronic materials. We have used synchrotron-based x-ray absorption spectroscopy to study the structure of iron silicon germanide films grown by molecular beam epitaxy. A series of Fe(Si1-xGex)2 thin films (2000 -- 8000å) with a nominal Ge concentration of up to x = 0.04 have been grown. X-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) measurements have been performed on the films. The nearest neighbor co-ordination corresponding to the β-FeSi2 phase of iron silicide provides the best fit with the EXAFS data. Temperature dependent (20 coefficient was calculated. Results suggest semiconducting behavior of the films which is consistent with the EXAFS results.

Conformational aspects of proteins at the air/water interface studied by infrared reflection-adsorption spectroscopy

NARCIS (Netherlands)

Martin, A.H.; Meinders, M.B.J.; Bos, M.A.; Cohen Stuart, M.A.; Vliet, van T.

2003-01-01

From absorption spectra obtained with infrared reflection-absorption spectroscopy (IRRAS), it is possible to obtain information on conformational changes at a secondary folding level of proteins adsorbed at the air/water interface. In addition, information on protein concentration at the interface

Impact effects of gamma irradiation on the optical and FT infrared absorption spectra of some Nd3+-doped soda lime phosphate glasses

Science.gov (United States)

Marzouk, M. A.; Elkashef, I. M.; Elbatal, H. A.

2018-04-01

The main aim of the present work is to study by two collective optical and FTIR spectral measurements some prepared Nd2O3-doped soda lime phosphate glasses before and after gamma irradiation with dose (9 Mrad). The spectral data reveal two strong UV absorption peaks which are correlated with unavoidable trace iron impurities beside extended additional characteristic bands due to Nd3+ ions. Gamma irradiation on the undoped glass produces slight decrease of the intensity of the UV absorption and the generation of an induced visible band and these effects are controlled with two photochemical reduction of some Fe3+ ions to Fe2+ ions together with the formation of nonbridging oxygen hole center (NBOHC) or phosphorous oxygen hole center (POHC). The impact effect of gamma irradiation on the spectra of Nd2O3-doped glasses is limited due to suggested shielding behavior of neodymium ions. FT-infrared spectra show vibrational modes due to main Q2-Q3 phosphate groups and the response of gamma irradiation of the IR spectra is low and the limited variations are related to suggested changes in some bond angles and bond lengths which cause the observed decrease to the intensities of some IR bands.

Recent advances in flexible and wearable organic optoelectronic devices

Science.gov (United States)

Zhu, Hong; Shen, Yang; Li, Yanqing; Tang, Jianxin

2018-01-01

Flexible and wearable optoelectronic devices have been developing to a new stage due to their unique capacity for the possibility of a variety of wearable intelligent electronics, including bendable smartphones, foldable touch screens and antennas, paper-like displays, and curved and flexible solid-state lighting devices. Before extensive commercial applications, some issues still have to be solved for flexible and wearable optoelectronic devices. In this regard, this review concludes the newly emerging flexible substrate materials, transparent conductive electrodes, device architectures and light manipulation methods. Examples of these components applied for various kinds of devices are also summarized. Finally, perspectives about the bright future of flexible and wearable electronic devices are proposed. Project supported by the Ministry of Science and Technology of China (No. 2016YFB0400700).

Determination of carbon content of UO2, (U, Gd)O2 and (U, Pu)O2 powders and sintered pellets - Combustion in a high-frequency induction furnace -Infrared absorption spectrometry

International Nuclear Information System (INIS)

2008-01-01

This International Standard describes a method for determining the carbon content in UO 2 , (U,Gd)O 2 and (U,Pu)O 2 powder and sintered pellets by combustion in an induction furnace and infrared absorption spectroscopy measurement. It is applicable for determining 10 μg/g to 500 μg/g of carbon in UO 2 , (U,Gd)O 2 and (U,Pu)O 2 powder and pellets. The sample is heated to a temperature above 1500 deg. C in an induction furnace, under pure oxygen atmosphere, to convert any carbon compounds to carbon dioxide gas. The resulting carbon dioxide gas is filtered and dried before measurement using infrared spectroscopy to measure the carbon dioxide signal at 2350 cm -1 . The result is converted into the carbon content of the material analysed

Propionaldehyde infrared cross-sections and band strengths

Science.gov (United States)

Köroğlu, Batikan; Loparo, Zachary; Nath, Janardan; Peale, Robert E.; Vasu, Subith S.

2015-02-01

The use of oxygenated biofuels reduces the greenhouse gas emissions; however, they also result in increased toxic aldehyde by-products, mainly formaldehyde, acetaldehyde, acrolein, and propionaldehyde. These aldehydes are carcinogenic and/or toxic and therefore it is important to understand their formation and destruction pathways in combustion and atmospheric systems. Accurate information about their infrared cross-sections and integrated strengths are crucially needed for development of quantitative detection schemes and modeling tools. Critical to the development of such diagnostics are accurate characterization of the absorption features of these species. In this study, the gas phase infrared spectra of propionaldehyde (also called propanal, CH3-CH2-CHO), a saturated three carbon aldehyde found in the exhaust emissions of biodiesel or diesel fuels, was studied using high resolution Fourier Transform Infrared (FTIR) spectroscopy over the wavenumber range of 750-3300 cm-1 and at room temperature 295 K. The absorption cross sections of propionaldehyde were recorded at resolutions of 0.08 and 0.096 cm-1 and at seven different pressures (4-33 Torr). The calculated band-strengths were reported and the integrated band intensity results were compared with values taken from the Pacific Northwest National Laboratory (PNNL) database (showing less than 2% discrepancy). The peak positions of the 19 different vibrational bands of propionaldehyde were also compared with previous studies taken at a lower resolution of 1 cm-1. To the best of our knowledge, the current FTIR measurements provide the first highest resolution infrared cross section data for propionaldehyde.

Commercialization issues and funding opportunities for high-performance optoelectronic computing modules

Science.gov (United States)

Hessenbruch, John M.; Guilfoyle, Peter S.

1997-01-01

Low power, optoelectronic integrated circuits are being developed for high speed switching and data processing applications. These high performance optoelectronic computing modules consist of three primary components: vertical cavity surface emitting lasers, diffractive optical interconnect elements, and detector/amplifier/laser driver arrays. Following the design and fabrication of an HPOC module prototype, selected commercial funding sources will be evaluated to support a product development stage. These include the formation of a strategic alliance with one or more microprocessor or telecommunications vendors, and/or equity investment from one or more venture capital firms.

Metal Halide Perovskite Single Crystals: From Growth Process to Application

Directory of Open Access Journals (Sweden)

Shuigen Li

2018-05-01

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

An Electronic Structure Approach to Charge Transfer and Transport in Molecular Building Blocks for Organic Optoelectronics

Science.gov (United States)

Hendrickson, Heidi Phillips

A fundamental understanding of charge separation in organic materials is necessary for the rational design of optoelectronic devices suited for renewable energy applications and requires a combination of theoretical, computational, and experimental methods. Density functional theory (DFT) and time-dependent (TD)DFT are cost effective ab-initio approaches for calculating fundamental properties of large molecular systems, however conventional DFT methods have been known to fail in accurately characterizing frontier orbital gaps and charge transfer states in molecular systems. In this dissertation, these shortcomings are addressed by implementing an optimally-tuned range-separated hybrid (OT-RSH) functional approach within DFT and TDDFT. The first part of this thesis presents the way in which RSH-DFT addresses the shortcomings in conventional DFT. Environmentally-corrected RSH-DFT frontier orbital energies are shown to correspond to thin film measurements for a set of organic semiconducting molecules. Likewise, the improved RSH-TDDFT description of charge transfer excitations is benchmarked using a model ethene dimer and silsesquioxane molecules. In the second part of this thesis, RSH-DFT is applied to chromophore-functionalized silsesquioxanes, which are currently investigated as candidates for building blocks in optoelectronic applications. RSH-DFT provides insight into the nature of absorptive and emissive states in silsesquioxanes. While absorption primarily involves transitions localized on one chromophore, charge transfer between chromophores and between chromophore and silsesquioxane cage have been identified. The RSH-DFT approach, including a protocol accounting for complex environmental effects on charge transfer energies, was tested and validated against experimental measurements. The third part of this thesis addresses quantum transport through nano-scale junctions. The ability to quantify a molecular junction via spectroscopic methods is crucial to their

Electron microscopy study of advanced heterostructures for optoelectronics

NARCIS (Netherlands)

Katcki, J.; Ratajczak, J.; Phillipp, F.; Muszalski, J.; Bugajski, M.; Chen, J.X.; Fiore, A.

2003-01-01

The application of cross-sectional transmission electron microscopy and SEM to the investigation of optoelectronic devices are reviewed. Special attention was paid to the electron microscopy assessment of the growth perfection of such crucial elements of the devices like quantum wells, quantum dots,

Nanocrystalline CsPbBr3 thin films: a grain boundary opto-electronic study

Science.gov (United States)

Conte, G.; Somma, F.; Nikl, M.

2005-01-01

CsPbBr3 thin films with nanocrystalline morphology were studied by using optoelectronic techniques to infer the grain boundary region in respect of the crystallite's interior performance. Co-evaporation of puri-fied powders or crushed Bridgman single crystals were used to deposit materials and compare recombina-tion mechanism and dielectric relaxation processes within them. Nanosecond photoconduction decay was observed on both materials as well as activated hopping transport. An asymmetric Debye-like peak was evaluated from impedance spectroscopy with a FWHM value, which remains constant for 1.25 +/- 0.02 deca-des, addressing the presence of a tight conductivity relaxation times distribution. The evaluated activation energy, equal to 0.72 +/- 0.05 eV, similar to that estimated by DC measurements, is well smaller then that expected for an intrinsic material with exciton absorption at 2.36 eV. A simple model based on Voigt's elements was used to model the electronic characteristics of these nanostructured materials, to discuss observed results and define the role played by grain boundaries.

Dual-band absorber for multispectral plasmon-enhanced infrared photodetection

International Nuclear Information System (INIS)

Yu, Peng; Ashalley, Eric; Wang, Zhiming; Wu, Jiang; Govorov, Alexander

2016-01-01

For most of the reported metamaterial absorbers, the peak absorption only occurs at one single wavelength. Here, we investigated a dual-band absorber which is based on simple gold nano-rings. Two absorption peaks can be readily achieved in 3–5 µ m and 8–14 µ m via tuning the width and radius of gold nano-rings and dielectric constant. The average maximum absorption of two bands can be as high as 95.1% (−0.22 dB). Based on the simulation results, the perfect absorber with nano-rings demonstrates great flexibility to create dual-band or triple-band absorption, and thus holds potential for further applications in thermophotovoltaics, multicolor infrared focal plane arrays, optical filters, and biological sensing applications. (paper)

The infrared properties of reusable surface insulations.

Science.gov (United States)

Schmitt, R. J.; Linford, R. M. F.; Dillow, C. F.; Hughes, T. A.

1973-01-01

The total infrared scattering and absorption cross sections of both flexible and rigidized high temperature fibrous insulations have been measured. The methods for accomplishing these measurements are described. Infrared reflection and transmission spectra were obtained to study the dependence of the total cross sections on the spectral characteristics of the transported radiation. These results are applied to steady-state effective thermal conductivity measurements via a four-flux model of radiative heat transfer to separate the radiative component and to calculate the effective thermal conductivity under transient heating conditions. Data for both silica and mullite fibers are presented.

Repetitively Mode-Locked Cavity-Enhanced Absorption Spectroscopy (RML-CEAS for Near-Infrared Gas Sensing

Directory of Open Access Journals (Sweden)

Qixin He

2017-12-01

Full Text Available A Pound-Drever-Hall (PDH-based mode-locked cavity-enhanced sensor system was developed using a distributed feedback diode laser centered at 1.53 µm as the laser source. Laser temperature scanning, bias control of the piezoelectric ceramic transducer (PZT and proportional-integral-derivative (PID feedback control of diode laser current were used to repetitively lock the laser modes to the cavity modes. A gas absorption spectrum was obtained by using a series of absorption data from the discrete mode-locked points. The 15 cm-long Fabry-Perot cavity was sealed using an enclosure with an inlet and outlet for gas pumping and a PZT for cavity length tuning. The performance of the sensor system was evaluated by conducting water vapor measurements. A linear relationship was observed between the measured absorption signal amplitude and the H2O concentration. A minimum detectable absorption coefficient of 1.5 × 10–8 cm–1 was achieved with an averaging time of 700 s. This technique can also be used for the detection of other trace gas species by targeting the corresponding gas absorption line.

THE EXTENDED HIGH A ( V ) QUASAR SURVEY: SEARCHING FOR DUSTY ABSORBERS TOWARD MID-INFRARED-SELECTED QUASARS

Energy Technology Data Exchange (ETDEWEB)

Krogager, J.-K.; Noterdaeme, P. [Institut d’Astrophysique de Paris, CNRS-UPMC, UMR7095, 98bis bd Arago, F-75014 Paris (France); Fynbo, J. P. U.; Heintz, K. E.; Vestergaard, M. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Geier, S. [Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife (Spain); Ledoux, C. [European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago 19 (Chile); Møller, P. [European Southern Observatory, Karl-Schwarzschildstrasse 2, D-85748 Garching bei München (Germany); Venemans, B. P. [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

2016-11-20

We present the results of a new spectroscopic survey for dusty intervening absorption systems, particularly damped Ly α absorbers (DLAs), toward reddened quasars. The candidate quasars are selected from mid-infrared photometry from the Wide-field Infrared Survey Explorer combined with optical and near-infrared photometry. Out of 1073 candidates, we secure low-resolution spectra for 108 using the Nordic Optical Telescope on La Palma, Spain. Based on the spectra, we are able to classify 100 of the 108 targets as quasars. A large fraction (50%) is observed to have broad absorption lines (BALs). Moreover, we find six quasars with strange breaks in their spectra, which are not consistent with regular dust reddening. Using template fitting, we infer the amount of reddening along each line of sight ranging from A ( V ) ≈ 0.1 to 1.2 mag (assuming a Small Magellanic Cloud extinction curve). In four cases, the reddening is consistent with dust exhibiting the 2175 Å feature caused by an intervening absorber, and for two of these, an Mg ii absorption system is observed at the best-fit absorption redshift. In the rest of the cases, the reddening is most likely intrinsic to the quasar. We observe no evidence for dusty DLAs in this survey. However, the large fraction of BAL quasars hampers the detection of absorption systems. Out of the 50 non-BAL quasars, only 28 have sufficiently high redshift to detect Ly α in absorption.

Optoelectronics-related competence building in Japanese and Western firms

Science.gov (United States)

Miyazaki, Kumiko

1992-05-01

In this paper, an analysis is made of how different firms in Japan and the West have developed competence related to optoelectronics on the basis of their previous experience and corporate strategies. The sample consists of a set of seven Japanese and four Western firms in the industrial, consumer electronics and materials sectors. Optoelectronics is divided into subfields including optical communications systems, optical fibers, optoelectronic key components, liquid crystal displays, optical disks, and others. The relative strengths and weaknesses of companies in the various subfields are determined using the INSPEC database, from 1976 to 1989. Parallel data are analyzed using OTAF U.S. patent statistics and the two sets of data are compared. The statistical analysis from the database is summarized for firms in each subfield in the form of an intra-firm technology index (IFTI), a new technique introduced to assess the revealed technology advantage of firms. The quantitative evaluation is complemented by results from intensive interviews with the management and scientists of the firms involved. The findings show that there is a marked variation in the way firms' technological trajectories have evolved giving rise to strength in some and weakness in other subfields for the different companies, which are related to their accumulated core competencies, previous core business activities, organizational, marketing, and competitive factors.

Effects of intermolecular interactions on absorption intensities of the fundamental and the first, second, and third overtones of OH stretching vibrations of methanol and t-butanol‑d9 in n-hexane studied by visible/near-infrared/infrared spectroscopy

Science.gov (United States)

Morisawa, Yusuke; Suga, Arisa

2018-05-01

Visible (Vis), near-infrared (NIR) and IR spectra in the 15,600-2500 cm- 1 region were measured for methanol, methanol-d3, and t-butanol-d9 in n-hexane to investigate effects of intermolecular interaction on absorption intensities of the fundamental and the first, second, and third overtones of their OH stretching vibrations. The relative area intensities of OH stretching bands of free and hydrogen-bonded species were plotted versus the vibrational quantum number using logarithm plots (V = 1-4) for 0.5 M methanol, 0.5 M methanol‑d3, and 0.5 M t-butanol-d9 in n-hexane. In the logarithm plots the relative intensities of free species yield a linear dependence irrespective of the solutes while those of hydrogen-bonded species deviate significantly from the linearity. The observed results suggest that the modifications in dipole moment functions of the OH bond induced by the formation of the hydrogen bondings change transient dipole moment, leading to the deviations of the dependences of relative absorption intensities on the vibrational quantum number from the linearity.

Mid-infrared quantum cascade laser spectroscopy probing of the ...

Indian Academy of Sciences (India)

Aparajeo Chattopadhyay

2018-05-07

May 7, 2018 ... cm3 molecule. −1 s. −1 ... Quantum cascade laser; time-resolved mid-infrared spectroscopy; transient absorption; peroxy radicals .... peak of the laser emission profile. .... cal with O2 is a termolecular reaction (Eq. 3) and the.

Injection-seeded tunable mid-infrared pulses generated by difference frequency mixing

Science.gov (United States)

Miyamoto, Yuki; Hara, Hideaki; Masuda, Takahiko; Hiraki, Takahiro; Sasao, Noboru; Uetake, Satoshi

2017-03-01

We report on the generation of nanosecond mid-infrared pulses having frequency tunability, a narrow linewidth, and a high pulse energy. These pulses are obtained by frequency mixing between injection-seeded near-infrared pulses in potassium titanyl arsenate crystals. A continuous-wave external cavity laser diode or a Ti:sapphire ring laser is used as a tunable seeding source for the near-infrared pulses. The typical energy of the generated mid-infrared pulses is in the range of 0.4-1 mJ/pulse. The tuning wavelength ranges from 3142 to 4806 nm. A narrow linewidth of 1.4 GHz and good frequency reproducibility of the mid-infrared pulses are confirmed by observing a rovibrational absorption line of gaseous carbon monoxide at 4587 nm.

A whole-process progressive training mode to foster optoelectronic students' innovative practical ability

Science.gov (United States)

Zhong, Hairong; Xu, Wei; Hu, Haojun; Duan, Chengfang

2017-08-01

This article analyzes the features of fostering optoelectronic students' innovative practical ability based on the knowledge structure of optoelectronic disciplines, which not only reveals the common law of cultivating students' innovative practical ability, but also considers the characteristics of the major: (1) The basic theory is difficult, and the close combination of science and technology is obvious; (2)With the integration of optics, mechanics, electronics and computer, the system technology is comprehensive; (3) It has both leading-edge theory and practical applications, so the benefit of cultivating optoelectronic students is high ; (4) The equipment is precise and the practice is costly. Considering the concept and structural characteristics of innovative and practical ability, and adhering to the idea of running practice through the whole process, we put forward the construction of three-dimensional innovation and practice platform which consists of "Synthetically Teaching Laboratory + Innovation Practice Base + Scientific Research Laboratory + Major Practice Base + Joint Teaching and Training Base", and meanwhile build a whole-process progressive training mode to foster optoelectronic students' innovative practical ability, following the process of "basic experimental skills training - professional experimental skills training - system design - innovative practice - scientific research project training - expanded training - graduation project": (1) To create an in - class practical ability cultivation environment that has distinctive characteristics of the major, with the teaching laboratory as the basic platform; (2) To create an extra-curricular innovation practice activities cultivation environment that is closely linked to the practical application, with the innovation practice base as a platform for improvement; (3) To create an innovation practice training cultivation environment that leads the development of cutting-edge, with the scientific

Synchrotron-based far-infrared spectroscopy of nickel tungstate

International Nuclear Information System (INIS)

Kalinko, A.; Kuzmin, A.; Roy, P.; Evarestov, R.A.

2016-01-01

Monoclinic antiferromagnetic NiWO 4 was studied by far-infrared (30-600 cm -1 ) absorption spectroscopy in the temperature range of 5-300 K using the synchrotron radiation from SOLEIL source. Two isomorphous CoWO 4 and ZnWO 4 tungstates were investigated for comparison. The phonon contributions in the far-infrared range of tungstates were interpreted using the first-principles spin-polarized linear combination of atomic orbital calculations. No contributions from magnetic excitations were found in NiWO 4 and CoWO 4 below their Neel temperatures down to 5 K.

Noninvasive Optoelectronic Assessment of Induced Sagittal Imbalance Using the Vicon System.

Science.gov (United States)

Ould-Slimane, Mourad; Latrobe, Charles; Michelin, Paul; Chastan, Nathalie; Dujardin, Franck; Roussignol, Xavier; Gauthé, Rémi

2017-06-01

Spinal diseases often induce gait disorders with multifactorial origins such as lumbar pain, radicular pain, neurologic complications, or spinal deformities. However, radiography does not permit an analysis of spinal dynamics; therefore, sagittal balance dynamics during gait remain largely unexplored. This prospective and controlled pilot study assessed the Vicon system for detecting sagittal spinopelvic imbalance, to determine the correlations between optoelectronic and radiographic parameters. Reversible anterior sagittal imbalance was induced in 24 healthy men using a thoracolumbar corset. Radiographic, optoelectronic, and comparative analyses were conducted. Corset wearing induced significant variations in radiographic parameters indicative of imbalance; the mean C7-tilt and d/D ratio increased by 15° ± 7.4° and 359%, respectively, whereas the mean spinosacral angle decreased by 16.8° ± 8° (all P imbalance; the mean spinal angle increased by 15.4° ± 5.6° (P imbalance detected using the Vicon system. Optoelectronic C7'S1' correlated with radiographic C7-tilt and d/D ratio. Copyright © 2017 Elsevier Inc. All rights reserved.

Optical and Optoelectronic Property Analysis of Nanomaterials inside Transmission Electron Microscope.

Science.gov (United States)

Fernando, Joseph F S; Zhang, Chao; Firestein, Konstantin L; Golberg, Dmitri

2017-12-01

In situ transmission electron microscopy (TEM) allows one to investigate nanostructures at high spatial resolution in response to external stimuli, such as heat, electrical current, mechanical force and light. This review exclusively focuses on the optical, optoelectronic and photocatalytic studies inside TEM. With the development of TEMs and specialized TEM holders that include in situ illumination and light collection optics, it is possible to perform optical spectroscopies and diverse optoelectronic experiments inside TEM with simultaneous high resolution imaging of nanostructures. Optical TEM holders combining the capability of a scanning tunneling microscopy probe have enabled nanomaterial bending/stretching and electrical measurements in tandem with illumination. Hence, deep insights into the optoelectronic property versus true structure and its dynamics could be established at the nanometer-range precision thus evaluating the suitability of a nanostructure for advanced light driven technologies. This report highlights systems for in situ illumination of TEM samples and recent research work based on the relevant methods, including nanomaterial cathodoluminescence, photoluminescence, photocatalysis, photodeposition, photoconductivity and piezophototronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Apparatus and method for transient thermal infrared emission spectrometry

Science.gov (United States)

McClelland, John F.; Jones, Roger W.

1991-12-24

A method and apparatus for enabling analysis of a solid material (16, 42) by applying energy from an energy source (20, 70) top a surface region of the solid material sufficient to cause transient heating in a thin surface layer portion of the solid material (16, 42) so as to enable transient thermal emission of infrared radiation from the thin surface layer portion, and by detecting with a spectrometer/detector (28, 58) substantially only the transient thermal emission of infrared radiation from the thin surface layer portion of the solid material. The detected transient thermal emission of infrared radiation is sufficiently free of self-absorption by the solid material of emitted infrared radiation, so as to be indicative of characteristics relating to molecular composition of the solid material.

Development of a differential infrared absorption method to measure the deuterium content of natural water

International Nuclear Information System (INIS)

D'Alessio, Enrique; Bonadeo, Hernan; Karaianev de Del Carril, Stiliana.

1975-07-01

A system to measure the deuterium content of natural water using differential infrared spectroscopy is described. Parameters conducing to an optimized design are analyzed, and the construction of the system is described. A Perkin Elmer 225 infrared spectrometer, to which a scale expansion system has been added, is used. Sample and reference waters are alternatively introduced by a pneumatical-mechanical system into a unique F Ca thermostatized infrared cell. Results and calibration curves shown prove that the system is capable of measuring deuterium content with a precision of 1 part per million. (author)

INFRARED STUDIES OF HUMAN SALIVA. IDENTIFICATION OF A FACTOR IN HUMAN SALIVA PRODUCING AN INFRARED ABSORBANCE MAXIMUM AT 4.9 MICRONS

Science.gov (United States)

An absorption maximum was observed at 4.9 microns in infrared spectra of human parotid saliva. The factor causing this absorbance was found to be a...nitrate, and heat stability. Thiocyanate was then determined in 16 parotid saliva samples by a spectrophotometric method, which involved formation of

Optoelectronic properties of XIn{sub 2}S{sub 4} (X = Cd, Mg) thiospinels through highly accurate all-electron FP-LAPW method coupled with modified approximations

Energy Technology Data Exchange (ETDEWEB)

Yousaf, Masood [Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia); Dalhatu, S.A. [Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia); Murtaza, G. [Department of Physics, Islamia College, Peshawar, KPK (Pakistan); Khenata, R. [Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, 29000 Mascara (Algeria); Sajjad, M. [School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Musa, A. [Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia); Rahnamaye Aliabad, H.A. [Department of Physics, Hakim Sabzevari University (Iran, Islamic Republic of); Saeed, M.A., E-mail: saeed@utm.my [Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia)

2015-03-15

Highlights: • Highly accurate all-electron FP-LAPW+lo method is used. • New physical parameters are reported, important for the fabrication of optoelectronic devices. • A comparative study that involves FP-LAPW+lo method and modified approximations. • Computed band gap values have good agreement with the experimental values. • Optoelectronic results of fundamental importance can be utilized for the fabrication of devices. - Abstract: We report the structural, electronic and optical properties of the thiospinels XIn{sub 2}S{sub 4} (X = Cd, Mg), using highly accurate all-electron full potential linearized augmented plane wave plus local orbital method. In order to calculate the exchange and correlation energies, the method is coupled with modified techniques such as GGA+U and mBJ-GGA, which yield improved results as compared to the previous studies. GGA+SOC approximation is also used for the first time on these compounds to examine the spin orbit coupling effect on the band structure. From the analysis of the structural parameters, robust character is predicted for both materials. Energy band structures profiles are fairly the same for GGA, GGA+SOC, GGA+U and mBJ-GGA, confirming the indirect and direct band gap nature of CdIn{sub 2}S{sub 4} and MgIn{sub 2}S{sub 4} materials, respectively. We report the trend of band gap results as: (mBJ-GGA) > (GGA+U) > (GGA) > (GGA+SOC). Localized regions appearing in the valence bands for CdIn{sub 2}S{sub 4} tend to split up nearly by ≈1 eV in the case of GGA+SOC. Many new physical parameters are reported that can be important for the fabrication of optoelectronic devices. Optical spectra namely, dielectric function (DF), refractive index n(ω), extinction coefficient k(ω), reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω) and electron loss function are discussed. Optical’s absorption edge is noted to be 1.401 and 1.782 for CdIn{sub 2}S{sub 4} and MgIn{sub 2}S{sub 4}, respectively. The

Nustar Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231

Science.gov (United States)

Teng, Stacy H.; Brandt. W. N.; Harrison, F. A.; Luo, B.; Alexander, D. M.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.;

Importance of the green color, absorption gradient, and spectral absorption of chloroplasts for the radiative energy balance of leaves.

Science.gov (United States)

Kume, Atsushi

2017-05-01

Terrestrial green plants absorb photosynthetically active radiation (PAR; 400-700 nm) but do not absorb photons evenly across the PAR waveband. The spectral absorbance of photosystems and chloroplasts is lowest for green light, which occurs within the highest irradiance waveband of direct solar radiation. We demonstrate a close relationship between this phenomenon and the safe and efficient utilization of direct solar radiation in simple biophysiological models. The effects of spectral absorptance on the photon and irradiance absorption processes are evaluated using the spectra of direct and diffuse solar radiation. The radiation absorption of a leaf arises as a consequence of the absorption of chloroplasts. The photon absorption of chloroplasts is strongly dependent on the distribution of pigment concentrations and their absorbance spectra. While chloroplast movements in response to light are important mechanisms controlling PAR absorption, they are not effective for green light because chloroplasts have the lowest spectral absorptance in the waveband. With the development of palisade tissue, the incident photons per total palisade cell surface area and the absorbed photons per chloroplast decrease. The spectral absorbance of carotenoids is effective in eliminating shortwave PAR (solar radiation. However, most of the near infrared radiation is unabsorbed and heat stress is greatly reduced. The incident solar radiation is too strong to be utilized for photosynthesis under the current CO 2 concentration in the terrestrial environment. Therefore, the photon absorption of a whole leaf is efficiently regulated by photosynthetic pigments with low spectral absorptance in the highest irradiance waveband and through a combination of pigment density distribution and leaf anatomical structures.

Far-infrared spectral studies of magnesium and aluminum co ...

Indian Academy of Sciences (India)

Far-infrared absorption spectroscopy has been used to study the occurrence of var- ... density of the products was found to be about 83% of the X-ray density. ..... [15] B D Cullity, Elements of X-ray diffraction (Addison-Wesley Press, Reading, ...

Investigation of the effects of different carotenoids on the absorption and CD signals of light harvesting 1 complexes

NARCIS (Netherlands)

Georgakopoulou, S.; van der Zwan, G.; Olsen, J.D.; Hunter, C.N.; Niederman, R.A.; van Grondelle, R.

2006-01-01

Absorption and circular dichroism (CD) spectra of light-harvesting (LH)1 complexes from the purple bacteria Rhodobacter (Rba.) sphaeroides and Rhodospirillum (Rsp.) rubrum are presented. The complexes exhibit very low intensity, highly nonconservative, near-infrared (NIR) CD spectra. Absorption and

Cultivation of students' engineering designing ability based on optoelectronic system course project

Science.gov (United States)

Cao, Danhua; Wu, Yubin; Li, Jingping

2017-08-01

We carry out teaching based on optoelectronic related course group, aiming at junior students majored in Optoelectronic Information Science and Engineering. " Optoelectronic System Course Project " is product-designing-oriented and lasts for a whole semester. It provides a chance for students to experience the whole process of product designing, and improve their abilities to search literature, proof schemes, design and implement their schemes. In teaching process, each project topic is carefully selected and repeatedly refined to guarantee the projects with the knowledge integrity, engineering meanings and enjoyment. Moreover, we set up a top team with professional and experienced teachers, and build up learning community. Meanwhile, the communication between students and teachers as well as the interaction among students are taken seriously in order to improve their team-work ability and communicational skills. Therefore, students are not only able to have a chance to review the knowledge hierarchy of optics, electronics, and computer sciences, but also are able to improve their engineering mindset and innovation consciousness.

Fluorene-based macromolecular nanostructures and nanomaterials for organic (opto)electronics.

Science.gov (United States)

Xie, Ling-Hai; Yang, Su-Hui; Lin, Jin-Yi; Yi, Ming-Dong; Huang, Wei

2013-10-13

Nanotechnology not only opens up the realm of nanoelectronics and nanophotonics, but also upgrades organic thin-film electronics and optoelectronics. In this review, we introduce polymer semiconductors and plastic electronics briefly, followed by various top-down and bottom-up nano approaches to organic electronics. Subsequently, we highlight the progress in polyfluorene-based nanoparticles and nanowires (nanofibres), their tunable optoelectronic properties as well as their applications in polymer light-emitting devices, solar cells, field-effect transistors, photodetectors, lasers, optical waveguides and others. Finally, an outlook is given with regard to four-element complex devices via organic nanotechnology and molecular manufacturing that will spread to areas such as organic mechatronics in the framework of robotic-directed science and technology.

Infrared Line Intensities for Formaldehyde from Simultaneous Measurements in the Infrared and Far Infrared Spectral Ranges

Science.gov (United States)

Fissiaux, L.; Földes, T.; Tchana, F. Kwabia; Daumont, L.; Lepère, M.; Vander Auwera, J.

2011-06-01

Formaldehyde (H_2CO) is an important intermediate compound in the degradation of the volatile organic compounds (VOCs), including methane, in the terrestrial troposphere. Its observation using optical remote sensing in the infrared range relies on the 3.6 and 5.7 μm absorption bands. Band and individual line intensities have been reported in both ranges. With the present work, we aim to also derive infrared line intensities for formaldehyde, however relying on pure rotation line intensities and the known electric dipole moment to determine the particle density. Indeed, because formaldehyde polymerizes or degrades easily, the gas phase may contain polymerization or degradation products. Spectra of H_2CO diluted in 10 hPa of N_2 were therefore simultaneously recorded in the 20-60 Cm-1 and 3.6 μm ranges, respectively using a Bruker IFS125HR Fourier transform spectrometer and a tunable diode laser. see A. Perrin, D. Jacquemart, F. Kwabia Tchana, N. Lacome, J. Quant. Spectrosc. Radiat. Transfer 110 (2009) 700-716, and references therein

Study of Material Moisture Measurement Method and Instrument by the Combination of Fast Neutron Absorption and γ Absorption

International Nuclear Information System (INIS)

Hou Chaoqin; Gong Yalin; Zhang Wei; Shang Qingmin; Li Yanfeng; Gou Qiangyuan; Yin Deyou

2010-01-01

To solve the problem of on-line sinter moisture measurement in the iron making plant, we developed material moisture measurement method and instrument by the combination of fast neutron absorption and y-absorption. It overcomes the present existed problems of other moisture meters for the sinter. Compare with microwave moisture meter, the measurement dose not affected by conductance and magnetism of material; to infrared moisture meter, the measurement result dose not influenced by colour and light-reflect performance of material surface, dose not influenced by changes of material kind; to slow neutron scatter moisture meter, the measurement dose not affected by density of material and thickness of hopper wall; to the moisture measurement meter which combined by slow neutron penetrate through and y-absorption, there are definite math model and good linear relation between the measurement values, and the measurement dose not affected by material thickness, changes of material form and component. (authors)

Bimodal Exciplex Formation in Bimolecular Photoinduced Electron Transfer Revealed by Ultrafast Time-Resolved Infrared Absorption.

Science.gov (United States)

Koch, Marius; Licari, Giuseppe; Vauthey, Eric

2015-09-03

The dynamics of a moderately exergonic photoinduced charge separation has been investigated by ultrafast time-resolved infrared absorption with the dimethylanthracene/phthalonitrile donor/acceptor pair in solvents covering a broad range of polarity. A distinct spectral signature of an exciplex could be identified in the -C≡N stretching region. On the basis of quantum chemistry calculations, the 4-5 times larger width of this band compared to those of the ions and of the locally excited donor bands is explained by a dynamic distribution of exciplex geometry with different mutual orientations and distances of the constituents and, thus, with varying charge-transfer character. Although spectrally similar, two types of exciplexes could be distinguished by their dynamics: short-lived, "tight", exciplexes generated upon static quenching and longer-lived, "loose", exciplexes formed upon dynamic quenching in parallel with ion pairs. Tight exciplexes were observed in all solvents, except in the least polar diethyl ether where quenching is slower than diffusion. The product distribution of the dynamic quenching depends strongly on the solvent polarity: whereas no significant loose exciplex population could be detected in acetonitrile, both exciplex and ion pair are generated in less polar solvents, with the relative population of exciplex increasing with decreasing solvent polarity. These results are compared with those reported previously with donor/acceptor pairs in different driving force regimes to obtain a comprehensive picture of the role of the exciplexes in bimolecular photoinduced charge separation.

Nuclear physics and optoelectronics presence in industry, medicine and environment

International Nuclear Information System (INIS)

Robu, Maria; Peteu, Gh.

2000-01-01

This paper reveals applications of Nuclear Physics and Optoelectronics in numerous fields of interest in industry, medicine, environment. In the first part of the work basic elements are analyzed, among which: - the large possibilities offered by the investigation, analysis and testing techniques based on nuclear physics and optoelectronics; - the superior qualitative and quantitative characteristics of these techniques, with varied applicability in fields from industry, medicine and environment. These applications refers to: - elemental analyses of content and impurities; - non-destructive testing with X and gamma radiations; - investigations with radioactive and activable tracers in trophic chains as for instance, ground-vegetation-products-consumers-environment, including also the systemic pollution factors; - complex investigations in the interface tritium-vegetation-environment-humans; - techniques and radiopharmaceutical products for medical investigations; - determinations and automatic control for levels, density, thickness, humidity, surfaces covering; - monitoring by means of remote sensing for the evaluation of the environment, vegetation and pollution factors; - applications and production of laser and UV installations; - connections through optical fibres resistant to radiations; - imaging and medical bioengineering; - advances in X ray, laser and ultrasonic radiology; - monitoring with radiations beams. In the final part, there are presented examples of optoelectronics and nuclear physics applications in fields in industry, medicine and environment, with special stress on their basic characteristics and efficiency. (authors)

Surface science station of the infrared beamline at SPring-8

International Nuclear Information System (INIS)

Sakurai, M.; Moriwaki, T.; Kimura, H.; Nishida, S.; Nanba, T.

2001-01-01

An experimental station for surface science has been constructed at the infrared beamline (BL43IR) of SPring-8, Japan. The station utilizes synchrotron radiation in the energy range of 100-20000 cm -1 to perform infrared reflection absorption spectroscopy (IRAS) of surfaces. It consists of an experimental section, a preparation chamber, gas handling equipment and a pair of focusing optics. In situ observation of vibrational spectra is possible using both IRAS and high-resolution electron energy loss spectroscopy

The mechanism and properties of bio-photon emission and absorption in protein molecules in living systems

Science.gov (United States)

Pang, Xiao-feng

2012-05-01

The mechanism and properties of bio-photon emission and absorption in bio-tissues were studied using Pang's theory of bio-energy transport, in which the energy spectra of protein molecules are obtained from the discrete dynamic equation. From the energy spectra, it was determined that the protein molecules could both radiate and absorb bio-photons with wavelengths of energy level transitions of the excitons. These results were consistent with the experimental data; this consisted of infrared absorption data from collagen, bovine serum albumin, the protein-like molecule acetanilide, plasma, and a person's finger, and the laser-Raman spectra of acidity I-type collagen in the lungs of a mouse, and metabolically active Escherichia coli. We further elucidated the mechanism responsible for the non-thermal biological effects produced by the infrared light absorbed by the bio-tissues, using the above results. No temperature rise was observed; instead, the absorbed infrared light promoted the vibrations of amides as well the transport of the bio-energy from one place to other in the protein molecules, which changed their conformations. These experimental results, therefore, not only confirmed the validity of the mechanism of bio-photon emission, and the newly developed theory of bio-energy transport mentioned above, but also explained the mechanism and properties of the non-thermal biological effects produced by the absorption of infrared light by the living systems.

New Phases of YBaCuGeO Superconductors Identified from X-ray Diffraction and Infra-red Absorption Measurements

Science.gov (United States)

Abo-Arais, Ahmed; Dawoud, Mohamad Ahmad Taher

2005-01-01

X-ray powder diffraction patterns and infra-red absorption spectra have been evaluated and analysed for the Y1 Ba2 Cu3 O7-d - Gex compound samples prepared by the solid state reaction with x values ranging from 0.0 to 1.13. All samples show bulk superconductivity above liquid nitrogen temperature using the levitation test (Meissner effect). Samples with Ge content up to x = 0.2 have offset Tc between 83K and 92K while the sample with x = 1.13 shows semiconducting behavior above 100K. As a result of the solid state interaction between YBCO and Ge, new phases are observed and determined, mainly three phases are concluded from X-ray powder diffraction analysis: (i) Ba2GeO4 (ii) Y2BaCuO5 (iii) BaCO3. The unit cell parameters a, b and c of the orthorhombic superconducting phase are calculated for all the prepared samples. The anisotropy factor is evaluated and related to the new structural phases in YBCO-Ge composite system. The I-R absorption spectra for the samples with orthorhombic symmetry have been determined. The phonon modes between ~ 400 cm-1 and 630 cm-1 are attributed to the Cu - O octahedron and pyramid vibrations for the CuO2 -planes and CuO-chains, while the peaks in the range from ~ 700 cm-1 to ~ 860 cm-1 may be due to defects such as the new phase Ba2GeO4 and the green phase Y2BaCuO5. The obtained results are discussed according to the superconductor - semi-conductor composite model and with the phonon-mediated charge transfer between CuO2 -planes and CuO- chains through apex oxygen (BaO).

High-resolution far-infrared observations of the galactic center

International Nuclear Information System (INIS)

Harvey, P.M.; Campbell, M.F.; Hoffmann, W.F.

1976-01-01

A map at 53 μ with 17'' resolution and three-color observations at 53 μ, 100 μ, and 175 μ with approx.30'' beams of Sgr A are presented. Sagittarius A is resolved into two main sources, one associated with the cluster of strong 10 μ sources and another approx.45'' to the southwest coincident with a weak 10 μ source. The dust temperature peaks near the strong 10 μ sources, but the 100 μ and 175 μ fluxes and the far-infrared optical depth are greatest near the southwest source. The amount of dust required to explain the far-infrared emission is comparable to that observed in absorption in the near-infrared

Optoelectronic properties of doped hydrothermal ZnO thin films

KAUST Repository

Mughal, Asad J.; Carberry, Benjamin; Oh, Sang Ho; Myzaferi, Anisa; Speck, James S.; Nakamura, Shuji; DenBaars, Steven P.

2017-01-01

, or In were evaluated for their optoelectronic properties. Inductively coupled plasma atomic emission spectroscopy was used to determine the concentration of dopants within the ZnO films. While Al and Ga-doped films showed linear incorporation rates

Fourier-transform infrared spectroscopic studies of dithia ...

Indian Academy of Sciences (India)

We present here infrared absorption spectra of dithia tetraphenylporphine and its cation in the 450-1600 and 2900-3400 cm-1 regions. Most of the allowed IR bands are observed in pairs due to overall 2ℎ point group symmetry of the molecule. The observed bands have been assigned to the porphyrin skeleton and phenyl ...

Advances in wide bandgap SiC for optoelectronics

DEFF Research Database (Denmark)

Ou, Haiyan; Ou, Yiyu; Argyraki, Aikaterini

2014-01-01

Silicon carbide (SiC) has played a key role in power electronics thanks to its unique physical properties like wide bandgap, high breakdown field, etc. During the past decade, SiC is also becoming more and more active in optoelectronics thanks to the progress in materials growth and nanofabrication...

Transparency of Semi-Insulating, n-Type, and p-Type Ammonothermal GaN Substrates in the Near-Infrared, Mid-Infrared, and THz Spectral Range

OpenAIRE

Robert Kucharski; Łukasz Janicki; Marcin Zajac; Monika Welna; Marcin Motyka; Czesław Skierbiszewski; Robert Kudrawiec

2017-01-01

GaN substrates grown by the ammonothermal method are analyzed by Fast Fourier Transformation Spectroscopy in order to study the impact of doping (both n- and p-type) on their transparency in the near-infrared, mid-infrared, and terahertz spectral range. It is shown that the introduction of dopants causes a decrease in transparency of GaN substrates in a broad spectral range which is attributed to absorption on free carriers (n-type samples) or dopant ionization (p-type samples). In the mid-in...

Spectroscopy of the 4.6 - 4.7 micron interstellar absorption features

International Nuclear Information System (INIS)

Geballe, T.R.

1984-01-01

Perhaps the most successful application of spectroscopy to the study of interstellar solid state infrared absorption features has been in the case of the previously unidentified feature near 4.6 μm first seen in absorption toward the protostar W33A. Whereas the original spectrum of this object, obtained at a resolving power of 70, revealed only a single deep absorption feature, a later spectrum, using a single channel grating spectrometer at ten times the resolving power, indicates that it is made up of three separate components. The central narrow absorption feature at 2140 cm -1 (4.67 μm) coincides in wavelength precisely with that of solid CO. It and its unresolved shoulder at just lower frequency have now been seen quite commonly in absorption toward other protostars. The broad absorption seen in W33A at 2165 cm -1 (4.62 μm) is apparently much less common. (author)

Graduate studies on optoelectronics in Argentina: an experience

Science.gov (United States)

Fernández, Juan C.; Garea, María. T.; Isaurralde, Silvia; Perez, Liliana I.; Raffo, Carlos A.

2014-07-01

The number of graduate programs in Optoelectronics in Argentina is scarce. The current Optics and Photonics Education Directory lists only three programs. One of them was launched in 2001 in the Facultad de Ingeniería (College of Engineering), Universidad de Buenos Aires (UBA). This was the first graduate program in the field, leading to a Master Degree in Optoelectronics. This decision arose from the demand of telecommunications industries and several estate- or private-funded research institutions working with us in the fields of lasers, optics, remote sensing, etc. A great bonus was the steady work, during several decades, of research groups in the College on the development of different type of lasers and optical non destructive tests and their engineering applications. As happened in many engineering graduate programs in Argentina at that time, few non full-time students could finish their studies, which called for 800 hours of traditional lecture-recitation classes, and the Master Thesis. In recent years Argentine Education authorities downsized the Master programs to 700 hours of blended learning and we redesigned the Graduate Optoelectronic Engineering Program to meet the challenge, dividing it in two successive one year programs, the first aimed at a professional training for almost immediate insertion in the labor market (called Especialización en Ingeniería Optoelectrónica), and the second (called Maestría en Ingeniería Optoelectrónica y Fotónica) aimed at a more academic and research target to comply with the UBA standards for Master degrees. The present work is a presentation of the new program design, which has begun in the current year.

Opto-electronic devices from block copolymers and their oligomers.

NARCIS (Netherlands)

Hadziioannou, G

1997-01-01

This paper presents research activities towards the development of polymer materials and devices for optoelectronics, An approach to controlling the conjugation length and transferring the luminescence properties of organic molecules to polymers through black copolymers containing well-defined

Photoionization-driven Absorption-line Variability in Balmer Absorption Line Quasar LBQS 1206+1052

Energy Technology Data Exchange (ETDEWEB)

Sun, Luming; Zhou, Hongyan; Ji, Tuo; Jiang, Peng; Liu, Bo; Pan, Xiang; Shi, Xiheng; Zhang, Shaohua [Polar Research Institute of China, 451 Jinqiao Road, Shanghai (China); Liu, Wenjuan; Wang, Jianguo [Yunnan Observatories, Chinese Academy of Sciences, Kunming, Yunnan (China); Wang, Tinggui; Yang, Chenwei [Department of Astronomy, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui (China); Miller, Lauren P., E-mail: lmsun@mail.ustc.edu.cn [Lehigh University, 27 Memorial Drive West, Bethlehem, PA 18015 (United States)

2017-04-01

In this paper we present an analysis of absorption-line variability in mini-BAL quasar LBQS 1206+1052. The Sloan Digital Sky Survey spectrum demonstrates that the absorption troughs can be divided into two components of blueshift velocities of ∼700 and ∼1400 km s{sup −1} relative to the quasar rest frame. The former component shows rare Balmer absorption, which is an indicator of high-density absorbing gas; thus, the quasar is worth follow-up spectroscopic observations. Our follow-up optical and near-infrared spectra using MMT, YFOSC, TSpec, and DBSP reveal that the strengths of the absorption lines vary for both components, while the velocities do not change. We reproduce all of the spectral data by assuming that only the ionization state of the absorbing gas is variable and that all other physical properties are invariable. The variation of ionization is consistent with the variation of optical continuum from the V -band light curve. Additionally, we cannot interpret the data by assuming that the variability is due to a movement of the absorbing gas. Therefore, our analysis strongly indicates that the absorption-line variability in LBQS 1206+1052 is photoionization driven. As shown from photoionization simulations, the absorbing gas with blueshift velocity of ∼700 km s{sup −1} has a density in the range of 10{sup 9} to 10{sup 10} cm{sup −3} and a distance of ∼1 pc, and the gas with blueshift velocity of ∼1400 km s{sup −1} has a density of 10{sup 3} cm{sup −3} and a distance of ∼1 kpc.

A parameterization for the absorption of solar radiation by water vapor in the earth's atmosphere

Science.gov (United States)