bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous electron and hole tunneling in coupled triple quantum wells
Authors: Tobin M.S. , Bryant G.W. , Leavitt R.P. , Bradshaw J.L.
Published: February 2023

We are investigating triple quantum-well (TQW) structures, in which carrier generation occurs in the central well and charge transfer occurs to the wells on either side of the central well. These structures should provide greater flexibility than coupled double-well structures for the control of charge transfer between the wells. Using effective mass and tight-binding models, we have designed TQW GaAs/AlGaAS structures to have a simultaneous resonance such that resonant electron transfer occurs to one side well and resonant hole transfer occurs to the other side well at the same bias. We have grown by MBE TQW structures designed to have a simultaneous electron-hole resonance and, for comparison, samples with only an electron resonance and others with only a hole resonance. The resonances have been identified by photocurrent spectroscopy. The dynamics of carrier recombination and charge transfer have been investigated by time-resolved photoluminescence and will be described.
Peripheral color vision—one size scale or many?
Authors: Gordon James
Published: February 2023

Color vision in the periphery is improved by increasing stimulus size. However, can the sizes of peripheral stimuli be scaled to elicit equivalent sensory functions? Is it possible to equate peripheral functions to each other even though none of them is like the foveal function? Many of the size scales that have been developed simply specify the factors by which peripheral stimuli have to be increased. However, the specified peripheral sizes may not be necessary—smaller may be sufficient at any locus: these scales should be referred to the minimal size for a particular foveal function. We will reexamine existing discrimination and matching data, as well as our own estimates of color appearance from hue and saturation scaling. We will show that the size scales are not the same for all sensory qualities: different aspects of peripheral color vision may be determined at different levels of the visual system. We will describe the necessary constraints imposed by these findings on physiological models by using a very general opponent-process model, the spectral loci of the unique hues can be used to derive the ratios of the different cone types and test how their combinations are affected by size at each of the peripheral locations.
Joint transform multi-target recognition via spatial domain synthesis and frequency domain filtering
Authors: Yu Francis T. S. , Cheng Feng , Gregory Don A.
Published: February 2023

There are two major drawbacks in a conventional joint transform correlator (JTC) for multi-target pattern recognition, i.e., the broad correlation profiles and the low energy efficiency. We have shown recently, by using an inverse reference power spectrum in the frequency domain for a JTC, that the output autocorrelation profiles can be sharpened dramatically. However, this technique was mainly used in a single reference function. For multi-target detection, the joint transform spectra should be compensated by each inverse reference spectrum. Since it is inefficient to perform this task in the frequency domain, in this paper we have used a spatially separable synthesis method to overcome this impediment, by which one-step peak-sharpening compensation can be achieved. To suppress the adverse spectral contents and remove some unwanted diffractions, frequency domain manipulation is also introduced. The effects due to the spectral dynamic range limit, the noise, and cluttering have been investigated. As compared with the conventional JTC, we have shown that the proposed system offers higher accuracy of detection, higher reliability, and higher diffraction efficiency.
Nonlinear correlation of two images based on their Fourier phases using binary joint transform correlation
Authors: Javidi B. , Wang J. , Tang Q.
Published: February 2023

The correlation performance of the binary joint transform correlator (JTC) is dependent on the threshold that is used to binarize the joint power spectrum in the Fourier plane.1 One type of threshold function is the sum of the power spectrum of the reference signal and the power spectrum of the input scene.1 Applying this threshold function in the binary JTC removes the Fourier magnitudes of both the reference signal and the input image. In other words, the Fourier magnitudes of the input signal and the reference signal are set to unity. It results in a nonlinear correlation between two images based on their Fourier phases only. This nonlinear correlator is different from the phase-only filter technique in which only the Fourier magnitude of the reference signal is set to unity. The thresholding function provides an optimal correlation performance by maximizing the autocorrelation peak intensity and eliminating the even-order harmonic terms in the output plane. Computer simulation and experiment results will be presented to illustrate the optimal correlation performance of the binary JTC using the thresholding function. Several different thresholding methods are also described and compared in the presentation.
Low-threshold diode laser arrays for holographic optical interconnects
Authors: Raja M. Y. A. , Srinivasan S. , Hersee S. , Sun S. , Brueck S. R. J.
Published: February 2023

For multichip modules (MCMs) holographic optical interconnects offer several advantages. Here, we present the design and fabrication of diode laser arrays for MCMs. In our case, the packing densities and the astigmatic beam are not the key issues; that is why edge-emitting arrays are chosen over vertical cavity surface-emitting lasers. 1-D arrays are fabricated from a single quantum well GRIN-SCH structure, designed to operate around 780 nm for detection efficiency of Si photodetectors integrated with the processing elements (PEs). Arrays are composed of 300 μm long 32/16 elements at 250/500 μm pitch, respectively. For data transmission between the PEs, the laser elements are independently addressable. Major features include low-threshold, mode stability, wavelength uniformity, and self-aligned bonding pads for integration with PEs, holographic elements, and Si mirror chips. Results will be presented to address these issues.
A video rate confocal laser scanning microscope
Authors: Kinzer David
Published: February 2023

A video rate confocal laser scanning microscope (CLSM) for biological applications has been developed for manufacture. This microscope is used for viewing thin "optical sections" of a sample by rejecting the signal from out-of-focus planes. The microscope consists of a multiline argon ion laser, a galvanometer and acousto-optic deflector (AOD) for video-rate scanning, and a lens system for coupling into a standard optical microscope stand. Performance of better than 1/4 wave peak-to-peak OPD is achieved for visible wavelengths, and operation has been extended to the UV (364 nm) for UV flash photolysis studies. This presentation will describe the design, performance tests, and experiences in manufacture of the CLSM. Techniques for handling chromatic aberration and the wavelength-dependent scan of the AOD will be presented.
Radiative lifetimes and energy transfer in CN(A2Πi)
Authors: Halpern Joshua B.
Published: February 2023

Radiative lifetimes were measured for the v′ = 2…7 levels of CN(A2Π
i
). The results were lower than predicted by theory, although the expected decrease in lifetime with increasing vibrational excitation was observed. Rapid collisional vibrational and electronic energy transfer was also seen. Ground state CN radicals were formed by the excimer laser photolysis of C2N2, followed by dye laser excitation of CN(A). Vibrational cascading in the A state was monitored by following the emission from A state vibrational levels. Electronic energy transfer was followed by exciting LIF from high vibrational levels of the ground state.
Temperature dependence of NO (A2∑+) electronic quenching by combustion species
Authors: Thoman J.W. , Gray J.A. , Durant J.L. , Paul P.H.
Published: February 2023

We report rate coefficients for electronic quenching of NO (A
2
∑
+
, v' = 0) by CH4, CO, CO2,H2O, O2, N2, Ar, and NO (X2∏) measured behind reproducible shock waves at temperatures in the range 1400 to 2300 K. High-temperature quenching cross-sections for CH4, Ar, O2, and NO (X2∏) are similar to those measured at room temperature. Cross-sections for H2O and CO2decrease, while those for N2 and CO increase with temperature. Modeling based on an ion-pair intermediate for the collision quantitatively predicts quenching rates for all reactant and product species in combustion environments.
Optical bistability in nonlinear periodic structures
Authors: Herbert Christopher J. , Malcuit Michelle S.
Published: February 2023

Optical bistability has been predicted to occur in periodic structures with a nonlinear index of refraction. This switching is expected to occur for frequencies within the stop gap of these structures at high intensities. We present the results of an experimental study of optical bistability in a distributive feedback structure with a large, thermal, nonlinear index of refraction. The structure we used was a 100 μm thick colloidal crystal consisting of 86 nm diameter, charged microspheres suspended in a solution of water and an absorptive dye. Optical switching to a highly transmitting state was found to occur at an incident intensity of approximately 300 kW/cm2, while switching back to a low transmitting state occurred at ≈150 kW/cm2. The dependence of the optical switching on the frequency detuning from the center of the stop gap and the time dependence of the switching have been studied, and these results will be presented. Our experimental results are compared to theoretical predictions of the transmission properties of nonlinear periodic structures, and good agreement is found between the theoretical predictions and the experimental results.
Direct measurements of total losses in vapor grown quartz glasses
Authors: Bukhshtab Michael
Published: February 2023

Results of studying low absorption plus scattering losses in pure glasses' bulk by direct attenuation measurements with very small numerical aperture NA
g
= 0.006 ÷ 0.012 in reflected laser radiation at λ = 632.8 nm are presented. In all studied glasses, including Corning-7940, an order of higher attenuation related to the same coefficient in fibers with NA
f
= 0.4 was observed. Experiment indicates the presence of essential small–angle scattering within the direction between NA
f
and NA
g
. Mean losses were about 80 dB/km at NAg =0.006 and 40 dB/km at NA
g
= 0.012. There are large inclusions compared with laser wavelength, and so higher attenuation (up to 120–200 dB/km) was found in vacuum pressure deposited quartz glass with low OH− content. In unclad fiber with NA
f
= 0.4 drawn from the last samples the total losses at λ = 1.3 and λ = 1.55 μm consisted of 1.6 and 0.9 dB/km, correspondingly. The lowest bulk attenuation found at NA
g
= 0.006 in fused quartz KV for region VI in 10 cm long sample that consisted of 16 ± 1 dB/km at a surface reflectance stability ±0.005%/h.
Capacity of wavelength multiplexed holographic memory
Authors: Gu Claire , Hong John
Published: February 2023

The use of various multiplexing methods to store data in volume holograms has been considered for high capacity data storage where compactness and large capacity are required. The two most prominent multiplexing methods are angular multiplexing1and wavelength multiplexing.2The capacity of angularly multiplexed volume holograms as limited by cross talk in readout has been shown3to be favorable for actual applications calling for gigabyte capacities. In this paper, we present new results in characterizing the capacity of wavelength multiplexed holographic memory. We describe the optimum geometry for implementing such a system and give expressions describing the output signal to cross talk ratio as a function of the number of stored holograms. The results will be compared with those for angularly multiplexed holograms.
Information capacity of cross talk free holograms
Authors: Pawluczyk Romuald
Published: February 2023

By considering a single, diffraction limited spot as a single bit of information and taking into account that the diffraction limited spot in Fourier domain is equivalent to a plane wave, it has been shown that maximal bit capacity N of a hologram is proportional to its overall surface S (not to its volume) and is given by the formula N = S / [2π(κλ)2]. κ is a coefficient defining a required distance between spots (κ = 0.61 if the Rayleigh criterion for resolution of two spots is applied), λ is the wavelength of the light used, and S is the total surface of the hologram (both sides of flat element). For coherent imaging the coefficient k should be increased at least three times, resulting in a decrease of capacity by one order of magnitude. This leads to the conclusion that the limit capacity of a volume hologram of a radius r is only twice the capacity of a flat hologram of the same radius. Thus, increasing the hologram thickness beyond that securing required efficiency, does not deliver any practical gain in information capacity.
Dispersionless optical cross-over bus interconnects using wavelength division multiple access
Authors: Li Yao , Jiang Tao , Rao Satish B.
Published: February 2023

Mirrors have been widely used in designs of large astronomical telescopes, mainly because of the following two advantages: (1) they provide a near dispersion-free transfer function and (2) they can be manufactured in much larger sizes than can glass lenses. Despite these advantages, mirror-based optical systems have not been recognized for their potentials in optical signal processing and data communications. Recent fiber communications research has shown that an efficient way of utilizing the existing fiber bandwidth while alleviating the bandwidth burden on the interfacing electronics is to use the wavelength division multiple-access (WDMA) scheme. The WDMA concept may also be applied to the parallel processing applications where communicating nodes are densely packed. To reduce the material dispersion-related signal cross talk in a WDMA-based parallel processing environment, it is desirable to use dispersionless optical networks based on mirror-type hardware. In this talk, a novel optical dispersionless cross-over bus network for the WDMA environment is presented. By using a three-stage routing algorithm, more than 100,000 densely packed WDMA communication nodes can be interconnected. System parameters, such as diffraction- and aberration-limited interconnect capacity, power distribution loss, etc., are discussed. The system is compared to various other optical networks in terms of power efficiency, space requirements, and hardware complexity.
Wavelength-space division switches
Authors: Sharony Jacob , Stern Thomas E. , Cheung Kwok W.
Published: February 2023

The concept of rearrangeably and strictly non-blocking space division networks1,2 is extended to the wavelength dimension, resulting in a new family of interconnection networks called wavelength-space division switches (WSDS's). A synergy is achieved by utilizing both the wavelength and space dimensions in a fully dynamic manner. This results in higher capacity, higher connectivity, and reduced complexity than either the "broadcast and select" wavelength networks or the purely spatial classical interconnection networks. The WSDS is a wavelength selective switch that can independently permute its inputs for each wavelength. It has N input fibers with M tunable transmitters placed on each input. Similarly, M tunable receivers are placed on each of the N output fibers. The total number of simultaneous connections is MN. By trading the spatial complexity to that in the wavelength dimension, connectivity can be increased and cost can be reduced. For wavelength-rearrangeable non-blocking switches the number of wavelengths needed is exactly M. For wavelength strictly nonblocking networks the sufficient number of wavelengths is 2M−1, independent of N. A numerical example shows how the spatial complexity can be traded with complexity in the wavelength dimension.
Hybrid interconnection system consisting of surface-emitting microlaser array and planar optics
Authors: Jahns J. , Morgan R. A. , Nguyen H. , Walker J. A. , Walker S. J. , Wong Y. M.
Published: February 2023

We report the hybrid integration of a monolithic array of surface-emitting microlasers onto a glass substrate that contains a matching array of microlenses and mirrors. The microlaser array is bonded onto the glass substrate by flip-chip solder bump bonding. An array of indium solder bumps simultaneously provides the electrical contacts to the lasers and the mechanical mounts between the chip and the substrate. The alignment precision is within a few micrometers. By using a reflow process, this precision can be improved to less than one micrometer. The optical substrate provides a simple interconnection scheme that routes the light from each laser to well defined output positions. The optics consists of diffractive, "binary optics" type lenses and mirrors that are all integrated on a single quartz glass substrate. The hybrid integration of the passive optics with optoelectronic devices using flip-chip bonding is an approach to make optical interconnections applicable to electronic VLSI systems.
Finite-difference time-domain simulation of ultrafast events in nonlinear, Fabry-Perot resonators
Authors: Basinger Scott A. , Brady David J.
Published: February 2023

We model optical fields in nonlinear thin film resonators by numerical integration of the dispersive Maxwell equations. We explore the use of non-linear resonators to extract pulse shapes from ultra-fast fields and the use of pulsed images to create spatial patterns in nonlinear resonators.
Causality and quantum detection theory
Authors: Hirota Osamu
Published: February 2023

Problems on the detectability of different quantum states have been discussed as the most interesting topics in the many research fields.
Passive glass integrated optical components for optical communications
Authors: Honkanen Seppo
Published: February 2023

Optical fibers are emerging rapidly in telecommunication and CATV subscriber networks.
Coherent beam summation—an examination of the effect of efficiency on the feasibility of power scaling
Authors: Schuster Gregory L. , Andrews John R.
Published: February 2023

An important consideration for power scaling arrays of semiconductor laser amplifiers is the system efficiency, as it adversely affects the system size, mass, and achievable power.
Feedback stabilization of semiconductorlaser arrays
Authors: Andersen David R. , Dasgupta Soura
Published: February 2023

One of the important proposed techniques for increasing the total power emitted from a semiconductor diode-injection laser stripe is to create a scheme whereby several nearly-identical laser stripes are fabricated in close juxtaposition in order that evanescent mode-coupling which occurs will cause them to phase-lock and behave in a well-ordered fashion, emitting light of a single frequency and little phase noise.
Correlation performance for partial inputs
Authors: Khoury Jehad , Gianino Peter D. , Kane Jonathan S. , Woods Charles L.
Published: February 2023

Holographic associative memories (HAM’s) are one common example of pattern recognition devices. Typical HAM’s are based upon the optical correlator with a matched filter as the memory element.
Optimum correlation in signal-dependent image noise
Authors: Downie John D. , Walkup John F.
Published: February 2023

We examine the effects of signal-dependent image noise sources on the performance of optical correlators. Several different models of realistic image-dependent noise are studied, including film-grain noise and speckle.
A new and better circular-harmonic filter
Authors: Gualdron Oscar , Arsenault Henri H.
Published: February 2023

Phase-only filters generally have better discrimination ability than normal filters. Rotation-invariant Circular harmonic (CH) filters that use only one component of the target generally don’t have sufficient discrimination to classify complex objects, unless they are realized as phase-only filters.
Optical on-axis phase-dominant filter using liquid-crystal television
Authors: Paul-hus Gilles , Sheng Yunlong
Published: February 2023

We have built a real-time Vander Lugt type optical correlator using a liquid crystal television (LCTV) encoding the on-axis phase-only filter (POF) in the Fourier plane.
The fabrication and testing of a high-damage-threshold, UV transmissive, lens array telescope
Authors: Kellogg C. , Kubath K. , Maltsev A. , Kessler T.J.
Published: February 2023

A lens array telescope has applications with high-peak-power lasers for performing whole-beam Raman conversion experiments, while the individual lens arrays are useful as Shack-Hartmann wavefront sensors and as elements for laser phase conversion.
Practical implementation of an amplitude- modulated phase-only filter
Authors: Awwal Abdul A. S. , Ahmed Jamal U. , Karim Mohammad A. , Iftekharuddin Mohammad K.
Published: February 2023

We have shown recently that amplitude modulated phase only correlators are more powerful in terms of discrimination than the classical phase only filter.
Observation of mechanical forces exerted by and evanescent wave
Authors: Mertz Jerome , Hipp Michael , Marti Othmar , Mlynek Juergen
Published: February 2023

We report the observation of mechanical forces induced by an evanescent wave on a microscopic body.
Spatiotemporal effects on ultrashort optical pulses in nonlinear dispersive media
Authors: Ryan Andrew T. , Agrawal Govind P.
Published: February 2023

(I). Until recently, most work concerning the spatial characteristics of a beam propagating in a nonlinear dispersive medium was done using a quasi-cw approximation, i.e. neglecting dispersion.
Adaptation mechanisms in the rod visual system
Authors: Sharpe Lindsay T. , Hugenschmidt Harald
Published: February 2023

We have investigated the sensitivity regulation of the rod visual system as a function of time following sudden changes in background intensity.
A high power short wavelength FEL using the SLAC linac
Authors: Kim K.-J. , Pellegrini C. , Winick H.
Published: February 2023

We discuss the design and performance of a 2 to 4 nm FEL operating in Self Amplified Spontaneous Emission (SASE), using a photoinjector to produce the electron beam, and the SLAC linac to accelerate it to an energy of about 7 GeV.
Wind-imaging Michelson interferometer for a small satellite
Authors: Gault William A. , Shepherd Gordon G. , Ward William E.
Published: February 2023

The Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite has been making measurements of winds, temperatures and airglow emission rates from orbit for about two years.
Improved wavelength measurements in bismuth and neon with a Fourier-transform spectrometer
Authors: George Simon , Mehdad Mansour , Engleman Rolf
Published: February 2023

The ultra violet and visible emission spectrum of Bi I has been analyzed using data obtained from the Fourier Transform Spectrometer located at Kitt Peek National Observatory in Arizona.
Regenerative amplifier with negative feedback for enhanced amplitude stability and external synchronizability
Authors: Brown D. L. , Will I. , Roides R. G. , Merle C. K. , Skeldon M. D. , Seka W.
Published: February 2023

Regenerative amplifiers (regens) are increasingly used in large laser systems requiring precise external synchronizability combined with high amplitude stability and pulse width and shape versatility.
Rydberg atoms in strong magnetic fields
Authors: Kleppner Daniel
Published: February 2023

The nonrelativistic hydrogen atom in a strong magnetic field is among the simplest nonseparable quantum systems.
Spatiotemporal patterns and vortices in a photorefractive phase-conjugate resonator
Authors: Indebetouw G.
Published: February 2023

Phase-conjugate resonators have many potential applications in image processing which involve the transverse nature of the beam in a fundamental way.
Near-field luminescence spectroscopy and imaging
Authors: Harris T. D. , Grober R. D. , Trautman J. K. , Betzig E.
Published: February 2023

We will report on the application of tapered, metal coated, single mode optical fibers as illumination and collection optical elements for spectroscopy.
Terahertz optical-frequency comb generation
Authors: Brothers L. R. , Wong N. C.
Published: February 2023

We report on the experimental results of a high-frequency narrowband LiNbO3 electro-optic modulator that incorporates a microwave waveguide structure for phase-velocity matching between the optical and microwave fields.
Broadly tunable all-solid-state picosecond LBO optical parametric oscillator
Authors: Butterworth S. D. , McCarthy M. J. , Hanna D. C.
Published: February 2023

We recently reported the efficient and widely-tunable operation of an all-solid-state synchronously pumped optical parametric oscillator in lithium triborate (LBO).1
Fiber delivered cw Nd:YAG laser systems with powers as high as 3 kW and their applications
Authors: Filgas David M.
Published: February 2023

Recent advances in high power cw Nd:YAG lasers and fiberoptic beam delivery have resulted in commercial systems with powers up to 3 KW.
Maskless scanning technique for excimerlaser materials processing
Authors: McIntyre Kevin J. , Hahn Walter G. , Jones William F.
Published: February 2023

A variety of laser techniques for creating gradient material removal profiles have previously been developed. Many of these techniques have been applied to altering the surface figure of corneas among other optical surfaces.
Sub-Doppler jet-cooled electronic spectroscopy of metal-containing molecules
Authors: Simard Benoit
Published: February 2023

Metal containing molecules may be classified as follows: 1) refractory molecules, 2) van der Waals molecules, and 3) metal clusters.
How to use lasers with the Optics Discovery Kit
Authors: Knox Wayne H.
Published: February 2023

Compact, battery-operated visible laser diodes are now commercially available, and prices are dropping. In this lecture, we show how these lasers can be used with the OSA Optics Discovery Kit to demonstrate a number of important laser principles.
Target architecture for a metropolitan all-optical network
Authors: To Michael
Published: February 2023

(Summary not available.)
Narrow-band spectral filter made of singlemode and dual-mode fibers
Authors: Safaai-Jazi A. , Jagannathan J.
Published: February 2023

A narrow-band all-fiber spectral filter made of two optical fibers, one single-mode and the other dual-mode, is proposed.
Optoelectronic component modeling and system simulation
Authors: Lu Dau-Tsuong , Poon Wang P. , Lin Ting-Ting Y. , Lee Sing H.
Published: February 2023

Detailed system simulation before actual construction helps designers to verify system design under normal or adverse operating environments.
Improved angular response of degenerate four-wave mixing in K vapor
Authors: Glassner D. S. , Ai B. , Knize R. J. , Partanen J. P. , Hellwarth R. W.
Published: February 2023

Atomic vapors, such as Na, K, and Cs, have such a large and fast nonlinear response on or near resonances that they are capable of processing high resolution images with cw lasers at submicrosecond time scales.
Injection locking of 780-nm laser diodes with a double phase-conjugate mirror
Authors: Shimura Tsutomu , Tamura Masayuki , Kuroda Kazuo
Published: February 2023

We achieved mutually coherent oscillation of two laser diodes (LDs) with double phase conjugate mirror (DPCM).
Electrically and optically dually addressable spatial light modulator based on electron-trapping materials
Authors: Yang Xiangyang , Wrigley Charles Y. , Lindmayer Joseph
Published: February 2023

A novel spatial light modulator (SLM) is proposed based on Quantex’s electron trapping (ET) materials.
Computer-addressable SLM phase-modulation measurement in a nonideal environment
Authors: Yu Francis T. S. , Purwosumarto Purwadi
Published: February 2023

In conventional Mach-Zehnder Interferometer phase measurement, a very rigid working environment is needed to avoid the accuracy degradation of the result due to the stray low frequency vibration in the system.
Variation in the design for obtaining ultrafast laser pulse shaping through the use of liquid-crystal spatial light modulators
Authors: Lin C. , Littman M. G.
Published: February 2023

Our method has the advantage of lessening the detrimental effects due to the “dead” zone between pixels of liquid crystal spatial light modulators(SLM).
Hot spots in parametric fluorescence
Authors: Koch Karl , Cheung E. C. , Moore Gerald T. , Chakmakjian Stephen H. , Liu J. M.
Published: February 2023

A hot spot occurs in the angular distribution of the parametric fluorescence from a nonlinear crystal driven by a pump beam of finite cross section.
Photo transduction in primate rods
Authors: Schnapf Julie L.
Published: February 2023

Membrane current was recorded from single rod outer segments of human eye donors. Light responses were compared to psychophysical properties of human dark-adapted vision. 1) The spectral sensitivity of human rods could account for the scotopic luminosity function. 2) The “integration time” (or average duration) of the response to single photons in dark-adapted human rods was 300 msec. The analogous psychophysical parameter, “critical duration,” has a value of about 100 msec for human dark-adapted vision, suggesting that rod signals are high-pass filtered by later neural processing. 3) Background illumination reduced the amplitude of photon responses in human rods according to Weber’s law. The half-desensitizing intensity of 120 photoisomerizations/sec (∼14 sc td) was 100 to 10,000 times greater than the intensity needed to reduce human visual sensitivity by a factor of two. This indicates that background desensitization of rod-mediated vision cannot be attributed to a reduction in the size of the photon signals in the rods themselves. Background light also produced a modest reduction in the duration of rod photon signals.
Modifications of an excimer laser to meet wind-tunnel diagnostic requirements
Authors: Smith M. S. , Price L. L. , Jones J. H.
Published: February 2023

Laser Induced Fluorescence (LIF) techniques are used for determining the properties of oxygen bearing wind tunnel flowfields. The 193 nm (ArF) output of a tunable excimer laser is well suited for exciting the oxygen Schumann Runge bands. However, the performance of the excimer laser is critical because of the complex, high-temperature, chemically reacting flows of interest. The standard narrowband excimer laser output is approximately 90 percent narrow band and 10 percent broadband. Additional transitions will be excited because of this broadband output, resulting in erroneous fluorescence measurements. This paper will describe improvements to a Lambda Physik EMG150 excimer laser in order to correct this and other deficiencies. The laser operates in the single-pass oscillator amplification mode, eliminating the broadband amplifier output. A computer-controlled tuning device tunes the laser, and by monitoring reference cell LIF, the laser is locked onto the desired transition. Dual-wavelength output is achieved with an additional set of tuning optics, eliminating the need for a second laser for temperature measurements. Experimental oxygen and nitric oxide excitation spectra will be presented to illustrate the improved laser performance.
Optimization of cascaded optical limiters
Authors: Hagan D.J. , Xia T. , Said A.A. , Van Stryland E.W.
Published: February 2023

We present results of optical limiting experiments using optical geometries designed to increase the dynamic range over which limiters function without incurring optical damage.
Infrared optical transitions to above barrier states in asymmetric semiconductor heterostructures
Authors: Henderson Gregory N. , Gaylord Thomas K. , Glytsis Elias N. , Anemogiannis Emmanuel , West Lawrence C. , Roberts Charles W. , Asom Moses T.
Published: February 2023

An asymmetric GaAs/GaAlAs electron wave Fabry-Perot interference filter has been designed with two above-barrier quasi-bound states for infrared optical transitions.
Study of eigenvalue behavior in rigorous coupled-wave analysis (RCWA)
Authors: Minhas B. K. , Naqvi S. S. H. , Leland R.
Published: February 2023

Rigorous Coupled Wave Analysis (RCWA) is a popular method for the computational analysis of diffraction gratings due to its simplicity, rigor and the ease of implementation.
Validity of the scalar analysis of multilevel binary diffractive elements
Authors: Pommet Drew A. , Moharam M.G.
Published: February 2023

Simple transmission theory (STT) has dominated the analysis of multi-level binary gratings because of its ease, and lack and computational strain.
LCTV polarization characterization with a visible near-IR Mueller-matrix imaging polarimeter
Authors: Pezzaniti J. Larry , Chipman Russell A.
Published: February 2023

We have developed an accurate imaging polarimeter ( < 1% error) operating in the visible to near-IR.
Effects of intrasignal coupling in photo-refractive crystals
Authors: Yu Francis T. S. , Zhao Dazun
Published: February 2023

Applications of photorefractive (PR) material to holographic memory have frequently encountered with the problem of signal fidelity. It can be seen that as the reconstructed wave field emerges from the PR crystal, hologram image degradation may occur due to intra-signal photo-refractive coupling within the crystal.
Three mask paradigms for sub-half-micrometer photolithography
Authors: Levenson Marc D.
Published: February 2023

Phase-shifting masks of various types enhance the resolution and process window for high-resolution photolithography at the price of increased difficulty in mask design and fabrication.
Moiré interferometric techniques for lithography and alignment
Authors: Zaidi Saleem H. , Sharma Ashwani K. , Brueck S. R. J.
Published: February 2023

Interferometric techniques provide simple and inexpensive tools for large area manufacturing of periodic nano-scale structures, using multiple exposures and phase shifting techniques either at the same level or multiple levels of photoresist, complex one and two-dimensional structures, and devices can be fabricated.
Free-space optical shared CAM processor: its architectures, applications, and limitations
Authors: Li Yao , Ha Berlin , Wang Ting
Published: February 2023

Content-address-able memory (CAM) architectures have been proposed to handle various logic, arithmetic, and database operations in digital computation. An electronic CAM is usually based on a programmable logic array which does not permit multiple concurrent access due to the conductive guiding nature of the electronic signals. The existing coherent and incoherent optical CAM processors were all based on optical vector-matrix multipliers which also exclude such an important concurrent multiple memory access. In this talk, a free-space shared-CAM (SCAM) architecture is proposed which spatially multiplexes and demultiplexes the multiple input and output signals, respectively, for a set of completely parallel accesses to the identical CAM storage space. Instead of using either a space-variant holographic scheme or an nonlinear four-wave-mixing approach based on signal degeneracy for a required optical matrix multiplication, strictly space-invariant conventional optical component based system is suggested. The designed optical system is statistically analyzed by propagating its error probability from the input source array, through the memory matrix, to the output array. The memory density and its sharing capacity are estimated in order to deliver a high quality performance specified by a low cross-talk related error rate (10-15). Power consumptions of the proposed S-CAM for its maximum access capacity and at a range of clock speeds (100 MHz -1 GHz) are also calculated. The proposed optical S-CAM is expected to find its usage in many digital computation applications under a single instruction and multiple-data (SIMD) environment. Some proof-of principle experiments based on a pair of ferroelectric liquid crystal optical switch arrays were performed, their results will be presented.
Software environment for exploring advanced optical computing architectures II: implementation and examples
Authors: Chennankara B. , Wu Y-D. , Shen D-S , Bykovski V.
Published: February 2023

This paper gives the implementation details of the software environment described in an accompanying paper, referred to as WF1.0. The environment WF1.0 is a set of modules each of which realizes a data generation and/or data processing function Control of the modules operation is based on a dialog box user interface that allows the user lo specify an input WF and a medium parameters. detector characteristics, apertures, spatial light modulator (SLM) setup, etc as well as specify connections between the modules. After an optical configuration is specified, a computation run can be started by triggering an input module, say, the WF generator. The configuration also includes the measuring modules that monitor the results of optical computing and can be used to reconfigure dynamically the optical system configuration. Examples of various optical configurations are demonstrated including a programmable correlator and a resonator-based associative memory.
Spectroscopy of Na2 by Photoassociation of Ultracold Na in a Dark Magneto-Optical Trap
Authors: Wagshul M.E. , Lett P.D. , Ratliff L.P. , Rolston S.L. , Phillips W.D.
Published: February 2023

We have produced high resolution spectra of singly-excited Na2 produced by photoassociation in a dark MOT. Vibrational, rotational and hyperfine structure are clearly resolved.
Anomalous Polarization of High Harmonics in Atomic Gases
Authors: Weihe F. A. , Dutta S. K. , Bucksbaum P. H.
Published: February 2023

We show that the polarization of high harmonics (HHG) in atomic gases deviates from the incident laser polarization. This discovery supports recent scattering models of HHG.
3-D integration of thin-film devices for smart pixels
Authors: Jokerst Nan Marie
Published: February 2023

Optoelectronic devices have greater function and versatility when they are integrated with circuits to form smart pixels. Thin film optoelectronic devices separated from the growth substrate and bonded to foundry silicon circuits using standard microelectronic processes are particularly attractive for low cost, high performance smart pixels.
Silicon-based smart-pixels technologies
Authors: Esener Sadik C.
Published: February 2023

It is now widely recognized that free-space optical interconnects can be effectively used for implementing fast parallel computing and communication switching systems only if high speed smart pixels can be made available, manufactured and packaged at low cost. At UCSD, using flip-chip bonding, various devices combining logic circuits and light detectors on silicon with light modulators on Lead Lanthanum Zirconate Titanate (PLZT) (for phase modulation), and on III-V Multiple Quantum Wells (MQW) (for absorption modulation) have been investigated.
Stimulated concentration scattering of light in a stratifying solution
Authors: Davydov Michael A. , Shipilov Konstantin F.
Published: February 2023

We present the results of an experimental study of the stimulated scattering in stratifying aqueous solutions of 2,6 and 3,4 lutidine and picoline solution, which has a singularity.
Single-droplet liquid-crystal gratings embedded in a polymer matrix
Authors: Sutherland R. L. , Tondiglia V. P. , Natarajan L. V. , Bunning T. J.
Published: February 2023

Bragg gratings are formed by irradiating a prepolymer syrup in a holographic setup using the 488 nm line of an Ar ion laser.
A nondestructive tool used for identifying optical-fiber internal properties through light scattering
Authors: Monette J. A. D. , Gauthier R. C. , Roberge A.
Published: February 2023

Light scattered from the broad side of an optical fiber is used as a non-destructive tool to probe the internal properties of a test fiber.
Synchronization of mode-locked erbium-fiber lasers
Authors: Stock M. L. , Yang L. -M. , Andrejco M. J. , Fermann M. E.
Published: February 2023

Synchronously pumped mode locked erbium fiber lasers are described. Pump-induced phase modulation rather than gain modulation is used to periodically perturb the fiber laser cavity and to produce the all-optical equivalent of FM mode locking.
The effects of aberrations on axial response of a confocal scanning laser ophthalmoscope
Authors: Stargard M. , Munger R. , Campbell M. C. W.
Published: February 2023

An infinity corrected Confocal Scanning Laser Ophthalmoscope (CSLO) has been constructed using a system common to Confocal Scanning Laser Microscopes (CSLM’s). The CSLO uses the human optics as the objective lens to image the retina.
Spectral changes in the Mach–Zehnder interferometer
Authors: James Daniel F. V. , Agarwal Girish S.
Published: February 2023

The spectral interference law for a Mach–Zehnder interferometer is derived and is used to illustrate spectral changes arising by interference between beams having different degrees of correlation. The results are compared with those pertaining to Young’s interference experiment. The use of this instrument to recover phase information is also investigated.
Oversampling digital phase metrology for shot-limited interferometry
Authors: Mertz Lawrence N. , Wyntjes Geert
Published: February 2023

Oversampling with ordered dither can favorably change the noise versus bandwidth tradeoff relation of interferometric measurement. As a result, phase quantization errors may be reduced to less than shot noise for almost any laser power.
Holographic pattern generation with binary optics
Authors: Baker Kenneth M. , Shealy David L. , Jiang Wu
Published: February 2023

An internally photosensitive substrate is exposed by a diverging three-dimensional standing wave interference pattern generated by a compact holographic projector system. The projector system, using binary optics, creates a diverging lattice of hexagonal or square rod-like intensity maxima extending through the photosensitive substrate.
Vertical profiling of phytoplankton by ocean lidar
Authors: Asanuma Ichio
Published: February 2023

We have developed a method to estimate a vertical profile of phytoplankton in the surface layer of the ocean and applied this method to data observed by an ocean lidar on the equatorial Pacific ocean. The ocean lidar using the second harmonic of Nd.YAG laser has built to measure a laser excited fluorescence from phytoplankton and simultaneously a light scattered by suspended particles in the ocean.
Material-flaw detection and classification using optical interferometry, the Fourier transform, and an artificial neural network
Authors: Aye Tin M. , Yacoubian Araz , Kim Dai-Hyun , Jannson Tomasz
Published: February 2023

Automatic detection and classification of material flaws based on real-time holographic interferometry, optical Fourier transform and an electronic neural network approach is reported.
Mach-Zehnder interferometer in integrated optics on glass for chemical sensors
Authors: Elflein W. , Duport I. Schanen , Benech P. , Rimet R.
Published: February 2023

An integrated Mach-Zehnder interferometer is designed and fabricated in ordinary glass substrate: optical waveguides monomode at the wavelength of 0.78 μm are made in B270 glass, by ionic exchange in pure potassium nitrate molten salt at a temperature of 440 °C during 20 minutes, through a 2.5 μm large window in an aluminum thin film made by the standard lithographic process of microelectronics.
Acousto-optic implementation of wavelet transforms
Authors: DeCusatis C. , Das P.
Published: February 2023

Recently, there has been a great deal of interest in the application of wavelet transforms to optical signal processing.
Title not available
Authors: John Otten Colonel L.
Published: February 2023

The definition of aero-optics and the scope of this session will be discussed along with an introduction of the speakers.
Diffractive-optical-element design optimization of pattern-recognition filters
Authors: van der Gracht Joseph , Mait Joseph N.
Published: February 2023

Diffractive optical element (DOE) design techniques can be applied to the generation of pattern recognition filters for optical correlators, in which case the spatial light modulator (SLM) in the filler plane is thought of as a real-time DOE. The designer must first select the desired complex pattern recognition filter and then apply DOE design techniques to map the fully complex function onto the limited dynamic range SLM. To illustrate the procedure, we apply the techniques to the problem of implementing a matched filter with limited dynamic range Fourier plane SLM’s. We use computer simulations to evaluate the effectiveness of the technique. We quantify the performance by measuring the mean squared error between the ideal matched output and output from quantized filters. Numerical simulations indicate that the DOE method yields a significant improvement over direct quantization. The improvement in mean squared error comes, however, at the expense of light efficiency. The DOE technique has been applied to design of matched filters with binary phase, ternary phase, and phase-only SLM’s for coherent as well as incoherent optical correlators. The additional phase freedom in the incoherent design results in improved performance, but incoherent systems are limited to correlation with real positive reference scenes. A proof-of-principle laboratory experiment has been constructed to complement the numerical simulations.
Brain mapping with MRI and PET
Authors: Evans Alan C.
Published: February 2023

Recently, 3-D imaging and computer-intensive analysis have revolutionized the study of normal human neuroanatomy and information processing. 3-D images of anatomy (MRI) and function (PET, MRI) are resampled into a standardized coordinate space which allows quantitative cross-subject comparison. Coordinate transformation may be linear or employ image-warping algorithms to overcome residual anatomical differences evident in the MRI data. Within the standardized space, image segmentation algorithms label voxels according to tissue type (e.g. gray or white matter), anatomical region (e.g. thalamus) or cortical feature (e.g. pre-central sulcus). Population analysis then generates probabilistic atlases for each sub-class.
Amplitude squeezing and transition from lasing with inversion to lasing without inversion in a multilevel laser
Authors: Zhu Min Xiao Yifu
Published: February 2023

Considerable attention has been directed recently to the study of lasing without the need of population inversion. The optical coherence and quantum interference associated with the light amplification may lead to interesting statistical properties in inversionless lasers. Here we analyze a laser model that consists of an ensemble of closed multi-level (three or four levels) atoms driven by a single coherent field. Unlike conventional lasers where population inversion is maintained and kept at the threshold value for arbitrary laser output, the multi-level laser analyzed here can start lasing from population inversion and evolves from population inversion into non-inversion with the increasing atomic pumping. In other words, the system makes transition from light amplification by population inversion into light amplification by coherence. On the other hand, the system can be also made to start lasing without population inversion in any state basis. In both cases, initial inversion and non-inversion, which are controlled by the ratio of spontaneous decay rates, the laser well above threshold is always maintained by lasing without inversion (light amplification by coherence), and the laser intensity fluctuations may drop below the shot noise limit. Two factors contribute to the noise reduction: first, the disappearance of the population inversion leads to the depleted atomic population in the upper lasing state, which reduces the spontaneous emission noises; second, the fast coherent cycling of electrons between excited states leads to the highly regulated absorption and emission processes. We found that the combination of these two mechanisms can lead to the noise reduction in the laser output more than 50% below the shot-noise limit.