bluuebunny/crossref_metadata_2025 huggingface dataset:
Near-field optical characterization of quantum wells and nanostructures
Authors: Hess Harald F.
Published: February 2023

A spatial distribution of luminescent centers with sharp (<0.1meV), spectrally distinct emission lines are revealed in a GaAs/AlGaAs quantum wells[1] using low temperature nearfield scanning optical microscopy [2], a technique where a subwavelength source and/or detector of light in close proximity (<40nm) to the sample is used to probe with a resolution beyond the diffraction limit. These centers are the energy eigenstate components that comprise the inhomogeneously broadened line shape observed in standard far-field photoluminescence. Measurements as a function of temperature, magnetic field, and well width establish that these centers arise from excitons localized by quantum well thickness fluctuations. For sufficiently narrow wells, virtually all emission originates from such centers. Quantities such as diffusion (both thermal and tunneling), lateral confinement energies, lifetimes, g-factors from magnetic field induced spin splittings, diamagnetic energy coefficients of the luminescent states can now be measured at a site-by-site individual quantum level rather than averaged over a statistical distribution. This information can be used in turn to provide a direct local picture of the interface fluctuations and how they vary under different MBE growth conditions. Near-field microscopy/spectroscopy provides a means to access energies and homogeneous line widths for the individual eigenstates of these centers, and thus allows the luminescent components to be identified and characterized with the extraordinary detail previously limited to the realm of atomic physics.
Photon-Assisted Tunneling through a Quantum Dot
Authors: Jauhar S. , Orenstein J. , McEuen P. L. , Kouwenhoven L.P. , Nagamune Y. , Motohisa J. , Sakaki H.
Published: February 2023

It is now possible to confine electrons in all three dimensions in semiconductors, resulting in the formation of what is commonly called a quantum dot. Electrons in these dots exhibit striking classical and quantum effects. Because of their small size, quantum dots have low capacitance C, which leads to a non-negligible electrostatic energy change upon addition or subtraction of an electron from a dot. This energy e2/C, typically 0.5 meV, suppresses fluctuations in electron number, allowing for the controlled addition of electrons to the dot by applying a voltage to a gate electrode. Measuring the current through the dot as a function of this gate voltage results in observation of highly regular current peaks, the so-called classical Coulomb Blockade oscillations. As the electrons are completely localized, the energy spacing between levels in a dot may also be relevant. If this energy Δε is comparable to e2/C, features may be present in the current due to these so-called 0D states. The interplay between the classical Coulomb Blockade and the quantum states of a dot has been extensively studied by dc transport measurements [1].
Coherent Nonlinear Optical Spectroscopy of Semiconductor Microcavities
Authors: Wang Hailin , Shah Jagdeep , Damen T.C. , Jan W.Y. , Cunningham J.E.
Published: February 2023

In semiconductor microcavities, quantization of the photon modes can lead to a unique system where excitons couple coherendy to a single mode of photons. In this paper we present the first coherent nonlinear optical study of a composite exciton-cavity system. The results reveal coherent dynamical behaviors that are not accessible to linear measurements.
AlAs/AlGaAs intracavity Saturable Bragg Reflector for Femtosecond self-starting passive mode-locking
Authors: Knox W. H. , Tsuda S. , de Souza E. A. , Jan W. Y. , Cunningham J. E.
Published: February 2023

We introduce a new semiconductor structure and demonstrate its use as an intracavity femtosecond mode-locker. The structure consists of an AlAs/AlGaAs quarter-wave dielectric stack grown by molecular beam epitaxy. We insert a single quantum well into a quarter wave layer, as shown in Fig. 1a. The reflectivity spectrum (Fig. 1b) shows a characteristic Bragg reflection with a small dip at the exciton wavelength of 850 nm.
Simulation of High-Power Mid-IR Interband Cascade Laser
Authors: Vurgaftman I. , Meyer J. R. , Felix C. L. , Ram-Mohan L. R.
Published: February 2023

There is a critical need for high-power mid-infrared diode lasers to be used in such military and commercial applications as IR countermeasures, IR illumination, and long-range chemical sensing. To date, the highest reported cw output power from a semiconductor diode emitting in the 3-5 μm spectral region has been 215 mW/facet. This was obtained from a 250-μm stripe at 80 K,1 and cw operation has never been observed in a III-V diode laser above 175 K.2 Although output powers exceeding 1 W are readily attainable from near-IR (λ ≈ 1 μm) lasers operating at or near ambient temperature, mid-IR emitters are inherently at a disadvantage due to the inverse scaling of the differential slope efficiency (dP/dI) with wavelength. That is, while the same current is required to inject one electron-hole pair as in a near-IR diode laser, the energy of the photon that results is 3-5 times smaller. A recent breakthrough has been the demonstration that this fundamental limitation may be circumvented by employing a cascade geometry. The unipolar quantum cascade laser (QCL) of Faist et al.,3 which achieves lasing due to optical intersubband transitions, can in principle emit as many photons for each injected electron as there are periods in the structure. However, high cw operating temperatures and large cw output powers have not yet been reported, in part because the threshold current density is inevitably rather large owing to a rapid nonradiative phonon relaxation of the population inversion.
Femtosecond luminescence of semiconductor nanostructures
Authors: Deveaud B. , Haacke S. , Hartig M. , Ambigapathy R. , Joseph I. Bar , Taylor R.A.
Published: February 2023

Luminescence has been quite widely used for the study of semiconductor nanostructures, and more especially time resolved luminescence, due to the ease to get a luminescence signal. The interpretation of the results however is sometimes quite complex, and one generally finds that some care has to be taken for the results to be meaningful. In particular, the homogeneity of the excited density over the detected luminescence signal is a quite important parameter, also it is often desirable to work at the lowest possible densities.
Coulomb Contributions to Exciton Saturation in Room Temperature GaAs-AlxGa1-xAs Multiple Quantum Wells
Authors: Holden M. , Kennedy GT , Miller A.
Published: February 2023

A number of optoelectronic device applications of quantum well semiconductors depend on the saturation of exciton absorption features. Studies of exciton saturation at room temperature have resolved exciton-exciton interactions on timescales less than 300fs, and two distinct mechanisms based on phase space filling (PSF) and Coulomb effects caused by free carriers on longer timescales. Nonequilibrium carrier distributions were originally employed to separate Pauli exclusion and long range Coulomb effects [1]. More recently, optically induced circular dichroism was used to identify PSF and Coulomb exchange contributions [2]. However, Coulomb contributions can arise from both screening and collisional broadening. In this work, we have extended the use of circularly polarised ultrashort pulses to distinguish the two related Coulomb effects of screening and broadening and in addition, compared the relative contributions of excitons and free carriers to Coulomb contributions.
Locking of the Stimulated Emission of a Microcavity Laser to the Electron Spin Precession Clock
Authors: Berger J.D. , Hallstein S. , Schneider C. , Hilpert M. , Rühle W.W. , Gibbs H.M. , Khitrova G. , Jahnke F. , Koch S.W. , Oestreich M.
Published: February 2023

Spontaneous and stimulated emission properties of electronic states depend intimately on the electromagnetic environment to which they are coupled. Microcavities are of great fundamental and practical interest largely thanks to their ability to influence these emission properties. In the weak coupling regime of cavity quantum electrodynamics, a microcavity can either enhance or inhibit spontaneous emission, while the strong coupling regime is characterized by reversible vacuum Rabi oscillations. Stimulated emission properties are also greatly influenced by the nature of the intracavity field.
Spin-Gratings and In-Well Carrier Transport Measurements in GaAs/AlGaAs Multiple Quantum Wells
Authors: Riblet P. , Cameron AR , Miller A.
Published: February 2023

We have recently demonstrated [1] that transient electron spin gratings created by cross-polarised excitation pulses at a wavelength resonant with the heavy hole exciton, can provide a new and unique way of measuring in-well electron drift mobilities in semiconductor multiple quantum well structures. This compares with the usual transient grating method in which only the ambipolar diffusion coefficient can be determined [2]. A comparison of concentration and spin grating decay rates allows the direct measurement of both the electron and hole drift mobilities in the same sample. In this work we extend these measurements to GaAs/AlGaAs multiple quantum wells with different well widths and compare results obtained under conditions of exciton saturation and broadening.
High Resolution Nonlinear Laser Spectroscopy of Excitation and Relaxation Near the Band Edge in GaAs Quantum Well Structures
Authors: Steel D.G. , Bhattacharya P.K. , Remillard J.T. , Wang Hailin , Webb M.D. , Pamulapati J. , Oh J.
Published: February 2023

The linear and nonlinear optical properties near the fundamental band edge of GaAs quantum well structures are important for applications of these materials to devices as well as providing new insight into the effects of quantum confinement. Excitons dominate the optical spectrum in this region, however, the coupling of excitons to the applied radiation field is modified by dynamical interactions due to the coupling of the exciton to the surrounding crystal lattice and the vacuum radiation field. At room temperature, the exciton is quickly ionized by phonons resulting in an electron-hole plasma which modifies the optical properties due to the effects of bandfilling and exchange that lead to strong optical nonlinearities.1 At low temperature, the exciton is more stable and other effects such as spontaneous emission, tunneling, diffusion, and scattering from phonons and defects modify the optical properties. These processes can result in decay of the excitation as well as decay of the coherence or induced polarization between the initial and the excited state. In this paper, we describe the use of high resolution nonlinear laser spectroscopy based on four-wave mixing (FWM) to obtain lineshapes associated with the nonlinear susceptibility. The measurements provide new understanding of the physical processes associated with the relaxation of the exciton and the dynamics of the optical response. At low temperatures, FWM can often eliminate inhomogeneous broadening leading to a direct measurement of the exciton homogeneous lineshape.
Optically Detected Nuclear Magnetic Resonance of Nuclei within a Quantum Well
Authors: Flinn G.P. , Harley R.T. , Snelling M.J. , Tropper A.C. , Kerr T.M.
Published: February 2023

Despite the fact that spectra of nuclear resonances provide a powerful microscopic probe of condensed matter, NMR techniques have not hitherto been applied to the study of semiconductor heterostructures. The reason is that only a tiny fraction of the nuclei of the sample lie in the portion of interest and are not distinguishable in conventional NMR. We have demonstrated that the problem can be solved by using optical pumping and detection techniques, and have obtained NMR spectra of spatially selected lattice nuclei in a 200Å GaAs quantum well.
Demonstration of an Integrated Multiquantum Well Heterojunction Bipolar Transistor with Gain for Efficient Low Power Optical Switching
Authors: Hong S. C. , Li W. , Oh J. E. , Bhattacharya P. K. , Singh J.
Published: February 2023

An integrated low power optical device with cascadable properties is essential for general purpose optical processing systems. We propose and demonstrate such a device by placing an intrinsic GaAs/AlGaAs multiquantum well structure in the base collector region of an n- p-i-n heterojunction bipolar transistor. A gain of 50 is obtained by the MBE grown devices and efficient switching occurs due to the amplification of the negative resistance region of the exciton based photocurrent.
Excitonic Optical Nonlinearity in Two- and Three-Dimensional Semiconductors
Authors: Hiroshima Tohya
Published: February 2023

Recently, excitonic optical nonlinearities in direct-gap-semiconductors have attracted much attention and have been studied extensively [1]. Of particular interest are the nonresonant excitonic nonlinearities for their potential applications to ultrafast all-optical devices. The nonlinear optical properties of exciton systems result, in general, from the deviation of excitons from non-interacting ideal bosons. Not only the mutual interaction between excitons, but also the anharmonic excitonphoton interaction, contribute to the excitonic optical nonlinearity. In this paper we develope a simple theory for nonresonant excitonic optical nonlinearity in two- and three-dimensional semiconductors, treating the above mentioned two kinds of anharmonicity on an equal basis.
Dynamics and Linewidth Enhancement Factor in Long Wavelength Strained Layer Lasers
Authors: Ghiti A. , Batty W. , O’Reilly E. P. , Heasman K. C. , Adams A. R.
Published: February 2023

We have shown previously the benefits of strained layer structures for low threshold current, high quantum efficiency, long wavelength lasers with high To [1]. In this paper we briefly review the benefits and consider the influence of strain on the relaxation oscillation frequency fr and the linewidth enhancement factor α. We find the relaxation oscillation frequency is enhanced in a strained layer laser, while α is reduced by comparison with a lattice-matched quantum well laser.
Limits to Normal Incidence Electroabsorption Modulation in GaInAs/InP Multiple Quantum Well Diodes
Authors: Stevens P.J. , Parry G.
Published: February 2023

We have recently developed a technique for optimizing the design of GaAs/(GaAl)As MQW electroabsorption modulators and investigating their potential performance [1]. In this paper, we develop the same technique for the (GaIn)As/InP system whose operating wavelength of around 1600nm is close to that of the low loss window of optical fibres.
InGaAs-InP MQW Electro-Absorption Modulators
Authors: Guy DRP , Besgrove DD , Taylor LL , Apsley N , Bass SJ
Published: February 2023

InGaAs-InP multiple quantum well (MQW) structures are of particular interest for electro-absorption modulator applications because they offer the prospect of small, fast, monolithic spatial light modulator arrays compatible with the low loss optical fibre waveband at wavelength ~1.55μm. However, the QW absorption coefficients found in the InGaAs-InP system1 are significantly lower than those in the more widely studied GaAs-AlGaAs system2. This limits the changes in absorption coefficient provided by the quantum-confined Stark effect (QCSE) in InGaAs-InP, and hence the modulation attainable in single-pass structures3,4. A careful study of the QCSE in InGaAs—InP is therefore necessary to ensure that the full potential of this technologically important system is realised.
Cathodoluminescence Studies of Quantum Dots Etched from Single Quantum Well GaAs/AlGaAs
Authors: Clausen E. M. , Craighead H. G. , Harbison J. P. , Schiavone L. M. , Van Der Gaag B. , Florez L.
Published: February 2023

High resolution electron beam lithography combined with reactive ion etching has enabled the creation of GaAs structures a few tens of nanometers in lateral dimension.1 There have been several studies of luminescence from GaAs "quantum dot and wire" structures. However, reports differ as to the luminescence efficiency, peak shifts and spectral character. Photoluminescence studies of structures etched from GaAs/AlGaAs quantum well material have shown that nonradiative surface recombination typically results in no observable luminescence for quantum dots smaller than ~ 60 nm.2,3 Multiple quantum well wires have been fabricated with dimensions as small as 20 nm in cross section which still luminesce with an efficiency not degraded by the fabrication process.4 Photoluminescence measurements have indicated a spatial quantization in dots as large as 250 nm.5 Other photoluminescence measurements of various size dots show no decrease in luminescence efficiency,2 compared to unpatterned material and different spectral structure attributed to quantization effects for diameters around 60 nm.6 In contrast, Forchel et al. monitored the GaAs free exciton emission from a 4 nm thick quantum well etched into wires and observed a marked decrease in luminescence intensity with decreasing wire width.7
Ultrafast Optical Studies of Tunneling and Perpendicular Transport in Semiconductor Microstructures
Authors: Shah Jagdeep
Published: February 2023

Novel electronic properties of superlattices, double barrier diodes and other semiconductor microstructures have generated considerable current interest from fundamental as well as device points of views. One of the driving forces behind this interest is the possibility of novel high speed devices; e.g. Sollner et al [1] have shown very high frequency response for double barrier diodes. There are also a number of very interesting fundamental issues as proposed in the original work of Esaki and Tsu [2]. Some of this work has been recently reviewed by Esaki [3] and Capasso et al [4].
Electron Tunneling Times in Coupled Quantum Wells
Authors: Oberli D. Y. , Shah J. , Damen T. C. , Tu C. W. , Miller D. A. B.
Published: February 2023

The work by Esaki and Tsu on tunneling in superlattices1 has generated a considerable interest for the potential application of tunneling to real devices. The rapid progress of epitaxial growth techniques has led to the creation of novel semiconductor structures which exhibit quantum-size effects and tunneling such as the double-barrier resonnant tunneling structures or the superlattice p-i-n diodes2. Transport studies in these structures demonstrated Bloch transport through the superlattice minibands3, negative differential resistance in double barrier diodes4, field induced localization5. More recently, optical measurements have been performed in double barrier structures in order to gain some insight on space-charge buildup6 and escape rates7.
The Effect of Quasibound State Lifetime on the Speed of Resonant-Tunneling Diodes
Authors: Brown E.R. , Parker C.D. , Sollner T.C.L.G. , Huang C.I. , Stutz C.E.
Published: February 2023

Recent optical experiments have directly measured the quasibound-state lifetime in resonant-tunneling structures [1]. The results indicate that this lifetime is close to that predicted by the coherent model of the process. The present paper deals with the effect of this lifetime on the electrical response of the double-barrier diode at high frequencies.
Electric Field Dependence of the Tunneling Escape Time of Electrons from a Quantum Well
Authors: Norris T.B. , Song X.J. , Wicks G. , Schaff W.J. , Eastman L.F. , Mourou G.A.
Published: February 2023

Tunneling of electrons through thin barriers in semiconductor heterostructures is usually studied via the tunnel current through multiple barrier structures.1,2 Time-resolved photoluminescence has also been used to investigate the tunneling escape rate of an electron from a quantum well (QW) bounded on each side by a thin barrier.3 We have applied the same technique to investigate the electric field dependence of this tunneling.
Executive Summary
Authors: Maclin Arlene P.
Published: February 2023

The Research Center for Optical Physics (RCOP) held its inaugural forum on September 22-23, 1993. More than 100 people from industry, universities and federal agencies attended. Mr. Paul Holloway, Director of NASA Langley Research Center gave the keynote address and Dr. William Harvey, President of Hampton University gave the Welcome Address. Invited technical talks were given by Dr. Anthony Johnson from AT&T Bell Laboratories on Ultrafast Laser Spectroscopy ; Dr. Peter Delfyett from Bellcore on Photonic Networks and Dr. Donald Lyons from Hampton University on Fiber Optic Sensors.
Luminescence of Eu3+ :Y2O3 Powder Thermally Diffused into an Optical Fiber for Distributed Thermal Sensing
Authors: Bryant Alvin , Albin Sacharia , Buoncristiani A. M. , Rogowski R. S.
Published: February 2023

The lifetime, the linewidth and the integrated intensity of emission from lanthanide rare earths ions, substitutionally doped into crystalline hosts is sensitive to changes in the temperature and provides a good basis for thermometry. We have begun development of distributed temperature sensor integrated into an optical fiber using this temperature dependent emission spectra. Eu3+: Y2O3 powder was thermally diffused into an optical fiber; the fiber was placed in an oven, optically pumped, and the resulting luminescence entrained within the fiber was measured as it emerged from the fiber. We report here on a study of the temperature dependent lineshape of the emission at 611 nm which clearly shows a strong and regular dependence on temperature over the range of 300 to 1000 K. We describe the physical characteristics of the Y2O3 crystalline host and the Eu3+ luminescence center. A good fit to the measured temperature dependence of linewidth is obtained using a single phonon model. The strong temperature dependence of the observed linewidth suggests that there may be enhanced emission, which can be explained as the emission from two nearby Stark level transitions.
Continuous Wave Laser Output Dependence on the Crystal Length of a Tm:Ho:YLF Laser
Authors: Lee Hyung R. , Hwang In H.
Published: February 2023

A Tm:Ho:YLF(thulium:holmium:yttrium lithium fluoride) laser crystals with 6 at.% Tm and 0.5 at.% Ho doped has been investigated for 2.1 µm laser performance at room temperature. A 3 watts CW GaAlAs diode laser was used as the pump source for the longitudinal pump geometry. The laser output power and slope efficiency were measured with laser rods of different length. The 340 mW output power with 26% slope efficiency is obtained from a 4 mm long crystal.
Radiative Properties of Molecular Nitrogen Ions Produced by Penning Ionization and Argon Effects
Authors: Kim Suchan , Tabibi Bagher M. , Song Kyo D. , Choi Sang H. , Lee Ja H.
Published: February 2023

Molecular nitrogen ions,
N2+, are generated by the helium Penning ionization in a glow discharge chamber. In the B-X system of
N2+ the rotational lines of the most prominent band, 391.44 nm (0,0), are resolved by a 0.5 m-long scanning monochromator. Four vibrational lines of
N2+ are measured. A rotational temperature of tr = 304.6 K and a vibrational temperature of about 12000 K were measured. To define argon effects on the
N2+ emission, the 391.44 nm line intensity was analyzed.
N2+ radiation is reduced to half as argon added up to 50% to N2. This could be resulted in quenching or/and the charge exchange with either
N2+ or
N2+* by argon.
Scattering of Optical Radiation Propagating through the Atmosphere
Authors: Carswell Allan I.
Published: February 2023

Scattering processes in the atmosphere are summarized and their applications to remote sensing systems are reviewed. The development of new measurement techniques with laser sources are discussed.
Measurements of Free Radicals in the Atmosphere: Recent Advances in Laser Fluorescence Techniques
Authors: Anderson James G.
Published: February 2023

A fundamental understanding of the chemical transformations taking place in the Earth s atmosphere is only possible given detailed knowledge of the chain carrying free radicals responsible for those transformations. Recent advances in laser techniques for the detection of those radicals is reviewed.
Analysis of the DMSP-SSH/2 Sounder
Authors: Rosenberg A. , Hogan D. B. , Kleespies T. J. , Chahine M. T.
Published: February 2023

The SSH-2 infrared sounder aboard the DMSP satellite contains eight water vapor sounding channels: seven in the 18 µm - 28 µm region and one centered around 12.5 µm. The central frequencies of these channels and their spectral bandwidths1 are shown in Table 1. The information content, i.e.: the relative contribution to the measured radiance from different atmospheric layers, of the water vapor sounding channels and their sensitivity to changes in humidity and temperature at different layers has been analyzed. It is shown that while some of the channels measure radiation emitted from the lower troposphere, none of the channels is sensitive to changes in the water vapor amount near the surface. This is due to the fact that the changes in the atmospheric and the earth contribution to the radiance, as a result of a change in the surface humidity, tend to cancel each other, in particular if the temperature gradient near the surface is small.
Measurements of the Absorption Coefficients of Chlorine-Dioxide at CO2-Laser Wavelengths
Authors: Lundqvist S. , Ahlberg H. , Eng S.T.
Published: February 2023

The increasing amount of toxic compounds in the working environment has created a strong interest in developing new monitoring techniques that can measure the average, long term exposure to these species. A CO2-laser long-path differential absorption instrument is ideally suited for this purpose since it has a short response time and gives the path average concentration of the measured gas [1,2].
Radiance Pattern Recognition Method for Satellite Temperature Profile Retrieval
Authors: Thompson Owen E.
Published: February 2023

During various phases of research and study of the satellite temperature retrieval problem, the author has become increasingly intrigued by the influence of the first guess field on satellite retrievals. The general influence has been recognized fairly widely. In an early phase of operations, NOAA/NESS scientists were sufficiently concerned to use a numerical forecast profile as first guess rather than a climtological mean, as had been customary. The philosophy was that the result is significantly dependent on the first guess and that one would do better by entering the problem with a more accurate estimate of the ambient atmosphere when doing retrievals.
Speckle Phenomena in Laser Remote Sensing
Authors: Churnside J. H. , Yura H. T.
Published: February 2023

In a number of remote sensing applications, a laser pulse is transmitted into the atmosphere where it is scattered by aerosol particles. The backscattered portion is collected by the receiver and the detected signal is processed to obtain the quantity of interest. Since atmospheric aerosols are typically separated by many wavelengths of the illuminating light, laser speckle can be observed in the backscattered signal. A number of physical processes combine to determine the characteristics of the aerosol speckle pattern. The most important of these are discussed, along with their effects on the correlation properties of the backscattered light.
Performance of the MAPS Carbon Monoxide Experiment
Authors: Reichle Henry G. , Hesketh Wilfred D. , Holland J. Alvin , Sherrill Robert T. , Wallio H. Andrew , Casas Joseph C.
Published: February 2023

The MAPS (Measurement of Air Pollution from Satellites) experiment, which flew as part of the OSTA-1 payload on the second flight of the Space Shuttle (STS-2) during early November 1981, was the first attempt to measure a known air pollutant in the troposphere from an orbiting platform. The experiment was designed to remotely measure the mixing ratio of carbon monoxide in the middle and upper troposphere using a gas filter radiometer as the sensing instrument.
Phase function measurements of premier grade diesel fuel smoke
Authors: Winchester L. W.
Published: February 2023

Scattering of light by obscurants such as smoke particles has both civilian and military applications. Knowledge of the phase function or angular scattering pattern of the smoke is of great importance in the computation of radiative transfer in a smoke cloud as well as in characterizing the smoke particles. In order to calculate the phase function of a smoke particle, the size, shape, and complex index of refraction of the particle must be known. Once the phase function of a smoke cloud is known, the scattering corrections to measured attenuation coefficients may be computed. Since the size, shape and complex index of refraction of volatile and evolving smokes are hard to measure, measurements of the phase function of a smoke cloud will provide some information on particle properties such as size and shape as well as characeterize the scattering process.
Advanced Moisture and Temperature Sounder (AMTS) Multichannel Grating Spectrometer
Authors: Evans N. L. , Gilbert V.
Published: February 2023

For the past several years the Jet Propulsion Laboratory has supported the NASA in the conceptual design and performance evaluation of a passive infrared "Advanced Moisture and Temperature Sounder" (AMTS) atmospheric sounding system. Based on AMTS system performance simulation results, a set of goal AMTS instrument requirements were specified. A detailed conceptual design for a multichannel grating spectrometer instrument was then developed as a baseline for examining instrument and system performance interactions.
Remote Measurement of Atmospheric Species Using Gas Filter Correlation Spectroscopy
Authors: Russell James M.
Published: February 2023

The principles of gas filter correlation spectroscopy have been applied in several satellite experiments to measure atmospheric temperature and constituents. This paper describes the approaches used.
Tests of an Inversion Algorithm for Spectrally Resolved Limb Emission
Authors: Sharma R. D. , Zachor A. S.
Published: February 2023

Spectrally resolved infrared radiance profiles of the Earth's limb can be inverted to obtain vertical distributions of temperature and species concentration. The atmosphere below approximately 70 km, where LTE prevails and the undissociated CO2 distribution is known, can be probed using broadband limb measurements, as demonstrated by House and Ohring (1969), Gille et al (1975), Russell et al (1979), and others. The added dimension of spectral resolution offers the potential of obtaining umambiguous information in the non-LTE altitude regime. Zachor, Sharma, Nadile and Stair (1981), hereafter referred to as ZSNS, used a direct nonlinear technique to recover vertical profiles of excited nitric oxide concentration and kinetic temperature above 100 km altitude from spectral data obtained by the rocket-borne SPIRE CVF spectrometer (cf. Nadile et al (1977) and Stair et al (1981)).
Laser PRF Considerations in Coherent DIAL Applications
Authors: Harney R. C.
Published: February 2023

Coherent differential absorption lidar (DIAL) systems employing infrared lasers (such as CO2 or Ni:MgF2) promise to be extremely useful tools for remote sensing of atmospheric pollutants. Most research to date has concentrated on systems employing transverse electric discharge, atmospheric pressure (TEA) CO2 lasers. These are low pulse repetition frequency (PRF), high pulse energy devices and can be used to make DIAL measurements at very long ranges. However, it will be shown that in many applications TEA laser DIAL systems have greatly inferior performance to high-PRF repetitively Q-switched, cw discharge CO2 laser DIAL systems. Laser PRF is a major factor in determining coherent DIAL performance. In this paper we will quantify the effects of laser PRF on concentration measurement accuracy, maximum usable range, and ambiguous range.
All-Sky Image Tube Photographs of OH Airglow Phenomena during the July 5-6, 1982 Total Lunar Eclipse
Authors: Peterson Alan W. , Adams Gene W.
Published: February 2023

In preparation for joint observations of the mesosphere, preliminary observations were carried out during the July 5-6, 1982 lunar eclipse at both Albuquerque, N.M. and Brighton, Colorado. At Albuquerque, the almost cloud-less sky was photographed in the near infrared (650 to 850 nm), with a two stage electrostatically focused image tube viewing the entire sky through an 8-mm Nikon fish eye lens. Exposures of 3 and 10 sec were made every 5 minutes during the total phase of this long eclipse. A zenith photometer monitored the OH 8-3 band at 730 nm and sky background at 710 nm.
Aerosol Backscatter Measurements with a Coherent CO2 Laser Radar
Authors: Biron D. G.
Published: February 2023

One potential approach to monitoring atmospheric pollutants is the use of differential absorption lidar (DIAL). In this technique two laser pulses are transmitted: one laser pulse on a resonant absorption of the species being monitored and the other off resonance. The CO2 TEA laser has been successfully used to obtain path-averaged concentration measurements using a retroreflector or a topographical target1. The usefulness of this technique would be greatly increased by using a distributed scatterer such as the naturally occurring atmospheric aerosols. A CO2 TEA laser can provide sufficient peak power to perform this task; however data collection is limited by the low PRF's (1-100Hz) available. A possible alternative is a low pressure Q-switched CO2 laser in conjunction with a heterodyne receiver such as is currently being used for existing CO2 laser radar systems2. Heterodyne detection lowers the required transmitter power while the high PRF (20-50kHz) of a Q-switched laser reduces the data collection time. Such a system designed for DIAL operation could provide range-resolved blanket area coverage with high up-date rates (~1 per min.).
Remote Sensing by Infrared Heterodyne Spectroscopy
Authors: Mumma Michael J.
Published: February 2023

Infrared heterodyne spectroscopy provides a convenient and sensitive method for measuring the true intensity profiles of atmospheric absorption lines. Application of radiative transfer theory to the measured line shapes can then permit retrieval of either abundance or temperature profiles. Notable success has been achieved for the atmospheres of Mars, Venus, Jupiter, and the Earth. The principles and state-of-the-art of heterodyne spectroscopy will be reviewed and its usefulness will be demonstrated by discussing recent results.
Numerical Inversion Techniques for Passive Infrared and Microwave Atmosphere Remote Sensing
Authors: Chahine Moustafa T.
Published: February 2023

After over 20 years of experience with the interpretation of remote sensing data from weather satellites we still find our attention directed towards methods of inversion of infrared and microwave temperature (and moisture) sounding data. This is due in part to the fact that the mathematical problem here is fundamentally incomplete, and the accuracy of the solution invariably depends on the use of some forms of mathematical or physical constraints. Furthermore, in dealing with real data we encounter the problems of noise in observations, uncertainties about the optical properties of the atmosphere, and the presence of clouds and aerosols.
Troposphere: Weather and Climate
Authors: Susskind Joel
Published: February 2023

Weather and climate research involve the study and prediction of meteorological atmospheric properties, with regard to either short term fluctuations, or their mean values in space and time. A detailed understanding of the absorption and emission properties of the earth's atmosphere is essential to two major areas of weather and climate research. The first utilizes atmospheric absorption and emission properties to provide global monitoring of atmospheric conditions such as temperature, humidity, ozone, surface pressure and cloud cover, and ground conditions such as temperature, ground wetness and/or snow cover, and albedo. The second computes the radiative contribution to atmospheric and surface heating or cooling as a function of the above parameters. The following sections will briefly describe some of the major considerations in these areas. It will be shown that broad banded continuum features due to absorption from wings of distant lines, pressure induced absorption, or possible other sources such as water dimer absorption, are of primary importance for meteorological applications.
Atmospheric Problems in the Stratosphere and Mesosphere
Authors: Hudson Robert D.
Published: February 2023

Considerable interest has been engendered both within the scientific community and within the general public on the effects of anthropogenic disturbances on the stratosphere. The fact that life on the earth's surface depends upon a rather small amount of ozone in the stratosphere has been known for some time. This ozone layer filters harmful ultraviolet radiation from reaching the earth and life as we know it has developed within these restraints. It is only recently, however, that scientists have understood that the amount of ozone in the stratosphere is controlled by trace amounts of substances other than ozone. These substances can be roughly broken down into families, the nitrogen, oxygen, chlorine, hydrogen and sulfur families. The concern is as to whether human activities can add significantly to the natural trace substances in the stratosphere and affect the balance of ozone.
FT-IR Measurements of Cryo-Condensed Inert Trace Air Pollutants*
Authors: Cranos R. L. , Shaw M. , Long F. , Miller K. , Damon E. , Nordstrom R.
Published: February 2023

Many of the atmospheric gaseous pollutants which may affect the environment, such as chlorofluorocarbons, occur at concentrations between 1 ppt and 1 ppb. A number of methods to identify these pollutants and to determine their abundance quantitatively have been proposed. Hanst1,2 has described a cryogenic concentration technique which can provide quantitative estimates for a number of relatively inert gases which occur at the ppb level1’2 by using infrared spectroscopy.
Characterization of a UV Laser Induced Fluorescence System for Detecting Atmospheric NO
Authors: Bradshaw J.D. , Rodgers M.O. , Fischer S.D. , Davis D.D.
Published: February 2023

UV laser fluorescence detection of trace atmospheric gases under airborne conditions has been proven to be capable of detecting atmospheric OH in the sub-part-per-trillion (ppt) range.1 This system used a Nd:YAG pumped dye laser to produce <.5 mJ at 2819Å (via SHG) in order to pump the v′=−1 manifold of the A2Σ+ excited state of OH. The resulting fluorescence was monitored at 3095Å using a high throughput optical collection scheme. Davis, et al. recently reported the requirements necessary for detecting ppt levels of the atmospheric trace gases NO, SO2 and CH2O based on their already proven OH detection system.2 Presented here are the experimental details of such a system which has detected NO at the ppt level under atmospheric conditions.
Application of Spectroscopic Data To The Interpretation of Stratospheric Spectra
Authors: Mankin William G. , Coffey M. T. , Goldman Aaron
Published: February 2023

Infrared spectroscopy is one of the most powerful diagnostic methods for the study of atmospheric composition. One of its useful attributes is the ability to remotely sense portions of the atmosphere far from the instrument. This attribute is particularly useful when measuring strato-stratospheric trace gases as a function of latitude, since at many atitudes, especially in the tropics, there are no convenient balloon launch locations for in situ measurements.
Ground-Based mm-Wave Heterodyne Spectroscopy of Stratospheric Chlorine Oxide
Authors: deZafra R.L. , Barrett J. , Parrish A. , Solomon P. , Carlson E.R.
Published: February 2023

Chlorine oxide, formed in the catalytic cycle is an important monitor of the conversion of ozone to O2 by free chlorine in the stratosphere. Current models predict mixing ratios for CℓO peaking at a value < 1:109 near 35 km altitude (1), and model profiles give an integrated column density towards the zenith of < 2.5 × 1014 cm-2, making radiometric detection of emission lines extremely difficult through the intervening atmosphere. Heretofore, experimental detection has relied on balloon-born in-situ measurements (2) or on attempts at remote mm-wave (3) or IR detection (4) from high-flying aircraft or balloon platforms. We have developed and successfully used a ground-based mm-wave spectrometer employing some novel features to detect the J = 11/2 → 9/2 rotational transition of CℓO in emission at 204.352 GHz. Our observations were conducted near Amherst, Mass, (elevation ~ 300 m) above sea level) during the period mid-January to mid-April 1980.
Wavelength Dependence of Photochemical Hole-Burning Efficiency and Vibronic Structure in an Absorption Band
Authors: Horie Kazuyuki , Murase Norio , Ikemoto Makoto
Published: February 2023

Photochemical hole-burning(PHB) is a good tool for understanding the dynamics of host polymers as well as for realizing a high performance optical storage. The quantum efficiency for persistent hole formation, ϕ, is one of the essential parameters for the PHB phenomenon. If one is aware of some kinds of application, its value is preferable to be large. This is why the quantum efficiencies for several series of substances are measured and the efforts to find out the dominant factor for controlling these values are continued.1) As ever, these values are measured near the peaks of the lowest energy absorption bands. However, we noticed recently very large difference in quantum efficiencies of hole formation, ϕ, between the cases when the hole is burnt on the higher frequency slope or on the lower frequency slope of the lowest energy inhomogeneous absorption peak in the Q band of free base tetraphenylporphin derivatives.2) We also found out the wavelength dependences of the formation rate of satellite holes, which originate from the vibronic excitations of the dye molecules accompanied by the electronic excitation. These facts suggest that the lowest energy inhomogeneous absorption band is actually composed of several kinds of vibronic dye transitions, and the 0-0 absorption component is one of the portion of this absorption band.
Correlations between Dynamical Processes and Electric Field Effects in Perylene/n-Heptane Probed by Persistent Spectral Holes
Authors: Bogner U. , Attenberger T. , Bauer R.
Published: February 2023

Persistent spectral hole-burning (PSIIB) and thermally induced hole refilling in the Shpol‘skii system perylene/n-heptane and in the amorphous regions of polyethylene (PE) doped with perylene provides a microscopic model of the physical nature of the asymmetric double-well potentials (ADWP), which are characteristic for amorphous systems and crystalline solids with local disorder [1]. These ADWP have been originally introduced in order to explain anomalous acoustic and thermal properties of amorphous materials by the socalled two level systems, the existence of which is due to tunneling in double-well potentials (DWP) with appropriate parameters. In connection with phonon detection by hole refilling, meassured after irradiation of nanosecond heat pulses, a model for photophysical PSHB was presented which is based on spectral jumps (matrix-shift variations) caused by crossing over the barriers of ADWP [2]. Recently spectral jumps have been observed for single molecules [3].
The Mechanism Of The Irreversible Burning In Infrared Spectral Line By Laser Action On Silicates
Authors: Bondar Anatolii M. , Mukhamedgalieva Anel F. , Swedov Igor M.
Published: February 2023

The mechanism of infrared spectral line burning by the continuous and pulsed CO2 laser action on the silicates have been investigated. It has been established the selective excitation of localized vibrational mode up to breaking of covalent bonds with the selective sublimation of Si-O groups.
Stochastic theory of the transient hole burning in the systems with homo- and heterogeneous broadening
Authors: Kilin S.Ya. , Nizovtsev A.P.
Published: February 2023

Transient hole burning in the impurity crystals is studied by stochastic laser-dependent dephasing theory using the two random telegraph processes model for the frequency fluctuations.
Stimulated Echo Signal Processing
Authors: Kachru R.
Published: February 2023

High-speed signal processing is essential in many applications where large amounts of analog or digital data need to be analyzed and processed in real time. The existing techniques, however, suffer from either very limited capacity for storing reference signals or the lack of a rapid reprogramming capability, both of which are of vital importance in high-speed signal processing.
Experimental Tests of the Optical Bloch Equations for Solids
Authors: Szabo Alex
Published: February 2023

Following a brief review of laser frequency and time domain techniques for overcoming inhomogeneous broadening of optical transitions in solids, recent studies on the failure of the optical Bloch equations (OBE) in describing saturation and coherent transient phenomena in ruby will be discussed. Experiments using free induction decay (FID), as in the original work on the system Pr3+:LaF3 by DeVoe and Brewer1, as well as extensions to rotary echos2 and hole-burning3 will be described. At low fields (~ 0.4 T), the time and frequency domain linewidth variation with Rabi frequency agree provided care is taken to avoid line broadening caused by spectral diffusion4. Recent work at high fields (~ 5 T), where Cr-Cr electron spin flipping is suppressed5, shows that spectral diffusion decreases and the dephasing time increases. Observed frequency domain hole widths as narrow as 18 kHz (FWHM) have been obtained for the 4
A2(−1/2)→E¯(−1/2) optical transition in dilute ruby using a pump-probe technique4. Work with such narrow holes emphasizes the fundamental limits imposed by the uncertainty principle and as an aside, a thought experiment where single photons are transmitted through "frequency slits" will be discussed.
Spectral Hole-Burning and Holography in a Y2SiO5:Pr3+ Crystal
Authors: Holliday Keith , Croci Mauro , Vauthey Eric , Wild Urs P.
Published: February 2023

Plane wave holography is a method of producing and detecting weak spectral holes with very low background [1]. Its success relies upon hole-burning materials of excellent optical quality with strongly absorbing zero phonon lines such as dye doped polymers which have been extensively studied [2 and references therein]. Through an extension of this technique, image storage [3] and data manipulation [4] have been demonstrated in such materials. Here, we report the application of plane wave holography to a crystalline material, Y2SiO5:Pr3+, for the first time. Spectroscopic measurements of Y2SiO5:Pr3+ have not previously been reported.
Technical Limits of Absorptive PHB Memories
Authors: Ao R. , Kümmerl L. , Haarer D.
Published: February 2023

Frequency Domain Optical Storage (FDOS) based on the method of the Photochemical Hole-Burning (PHB) can be discussed as a possible successor of the present conventional optical storage schemes. The possibility of storing data in the frequency domain in addition to the two spatial dimensions enhances both the storage densities and the pertinent data access rates by more than one order of magnitude.
Low-Frequency Modes of Polymers Studied by Laser-Induced Fluorescence Line-Narrowing Technique
Authors: Kanematsu Y. , Ahn J.S. , Saikan S. , Kushida T.
Published: February 2023

The weighted density of the ’phonon’-states (WDOS), i.e., the density of states of low-frequency host modes weighted by the coupling strength between the optical center and individual host modes is important because it gives us valuable information on the dynamics of host materials. However, the WDOS in disordered systems has not been reported yet, because it is not easy to obtain it on account of large inhomogeneous broadening of the optical spectra.