bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental measurement of a Cs Faraday filter at 455 and 459 nm
Authors: Squicciarini M. F. , Scharpf W. J. , Billmers R. I. , Contarino V. M. , Allocca D. M. , Menders J.
Published: February 2023

The Faraday filter is studied for use in a lidar receiver system. The transmission of the Faraday filter is measured as a function of temperature and magnetic field for both the 455 and 459 nm lines of Cs. The measurements are made over a sufficiently wide frequency range in order to determine maximum transmission, hold-off, and effective bandwidth. Various types of polarizers are tested to determine their effect on the filter's field of view (FOV). A comparison between the theoretical model and experimental results is presented. An overall system trade-off study is presented for several different receiver systems.
Record nuclear polarization in optically pumped 3He gas using a high power LNA laser
Authors: Bigelow N. , Larat C. , Nacher P. J. , Leduc M.
Published: February 2023

Optical pumping is an efficient method for creating nuclear polarization M in a gas of 3He. M is first achieved in the metastable 23S state and then transfered to the ground state. Polarized 3He has numerous applications: quantum fluids, precision magnetometry, nuclear targets, etc. Much progress in achieving high values of M has resulted from the development of efficient IR lasers capable of exciting the 23S–23P3He transition at 1.08 μm. Using a novel lamp pumped LNA laser delivering 5 W cw, we have achieved M >85% for samples in the torr pressure range. To measure M we have developed an accurate technique based on the change as a function of M of the ratio between σ and π polarized light absorbed from a weak; probe beam by the 23S metastable atoms. The probe was delivered by a single mode tunable diode pumped LNA laser that was frequency modulated by using an étalon mounted on a galvoplate. M was also measured by monitoring the circular polarization of the 668 nm line emitted by the dis charge. Experimental and theoretical results on the optimization of the pumping will be presented, and the laser systems will be discussed.
A gradient index of refraction model of the human lens
Authors: Lemus T. , Lakshminarayanan V.
Published: February 2023

We present a model of the human lens utilizing three types of refractive index distributions: step function, parabolic, and linear gradient. Thicknesses, curvatures, and ray traces are calculated and compared among the models. We comment on the errors between our model and others. In addition, a generalized computer model of the index of re fraction for a human eye is illustrated.
Phase conjugation in the far infrared via intersubband third order nonlinearities in multiple quantum well structures
Authors: Gravé Ilan , Segev Mordechai , Yariv Amnon
Published: February 2023

We report on the observation of phase conjugation at 10.6 μm via intersubband third order nonlinearities in a multiple quantum well structure, in a phase matched configuration, yielding reflection efficiency of 0.2%. Our sample consists of 50 periods of heavily Si-doped, GaAs quantum wells, clad by AlGaAs barriers. The input facets were lapped to 45°. In our experiment, the light from a CO2 laser was split into two beams: the first, acting as the pump beam, was focussed onto the sample edge at normal incidence; the second (probe) beam was focussed at an angle of 15° from the normal. The (nor mal) reflection of the first pump beam from the back facet inside the sample provided the second counterpropagating pump beam, and the phase conjugate beam was obtained, retracing the path of the incident probe beam.
Compensation of phase distortions in conjugating media
Authors: Bashaw M. C. , Aharoni A. , Hesselink L.
Published: February 2023

Phase-conjugated light waves are known to reverse phase distortions in media with negligible absorption or for paraxial beam propagation.1 We examine here a different case in which a volume conjugating medium is itself imperfect, possessing phase distortions and a conjugating efficiency dependent on grating spatial frequency. We show theoretically that for multiplexed signals, cross-talk-free phase conjugation is obtained only for negligible spatial-frequency dispersion and a phase-conjugated reference wave. We further present experimental results in a severely striated sample of photorefractive strontium barium niobate; using a phase-conjugated reference wave, we demonstrate the alleviation of distortion2 and the elimination of cross talk between closely spaced angularly multiplexed signals.
Charge screening effects on optical erasure of encoded χ eff ( 2 ) ( 2 ω ; ω , ω ) gratings in semiconductor microcrystallite-doped glass
Authors: MacDonald R. L. , Lawandy N. M.
Published: February 2023

Optical erasure rates of optically encoded χ(2) gratings in semiconductor microcrystallite-doped glasses (SDG) have been measured for wavelengths above and below the semiconductor bandgap. Exposure of encoded SDG to light above the band gap (ħω>E
g
) results in erasure rates ~500 times larger than for ħω>E
g
′, indicating that free carriers play an important role. The intensity dependence for ħω>E
g
exhibits a surprising dip in the erasure rate with increasing intensity over the range 6-12 W/cm2, corresponding to a Debye screening length comparable to the crystallite diameter (d ~ 100 Å). A model for recombination of a trapped carrier with a particle in a 1-D box under a screened electric field predicts the observed intensity dependence if the trapped carrier is assumed to be outside the crystallite. The slow variation of erasure rate with wavelength for ħω>E
g
is consistent with ionization of trapped carriers, but the observed erasure rate is 6 orders of magnitude smaller than ionization rates calculated by using matrix elements from a δ-function trap to 3-D box states. If the trap is moved 5-10 Å outside the crystallite, the calculated rates agree with the experimental rates, indicating that the long lived traps used to encode the field are outside the crystallite.
Effects of system parameters on image transmission through fiber using self-pumped phase conjugation
Authors: Jeon Hyung Wook , Lee Yim Kul , Son Jung Young
Published: February 2023

Optical fiber image transmission using a barium titanate crystal for self-pumped phase conjugation is presented.1 An input object, the letter "K," illuminated by a collimated argon-ion laser beam (514.5 nm), is focused into a multimode fiber (50 μm core and step index mode) and then phase conjugated in the crystal. The phase conjugated image retraverses the same fiber to compensate for the modal dispersion of the fiber. For a given experimental setup, an optimum image quality was obtained qualitatively at f = 75.6 mm in the range of 60 mm to 200 mm. As f increased, the restored K was gradually de graded in quality and significantly deformed in shape, particularly at f = 200 mm. As f decreased (e.g., f = 60 mm), the character K became quite noisy at f = 60 mm because of the increase in high spatial frequency components contained in the restored image, and the size of speckles on the restored background was reduced. Increasing the illuminating beam intensity also caused the restored K to be deformed and blurred as the intensity was varied from 10 mW to 400 mW. A reasonably good result was obtained for a wide range of the beam intensity (e.g., from 100 to 300 mW) at f = 75.6 mm, while increasing or decreasing the intensity from 200 mW significantly deformed the letter K, particularly at f = 150 mm. No restoration of the input K was obtained for f = 200 mm at high power (e.g., 400 mW). Both qualitative and quantitative analysis will be presented under various experimental conditions.
Spatial light modulator optimization by phase locked write beam chopping
Authors: Hudson T. D. , Lanteigne D. J. , Reardon J. V.
Published: February 2023

An interesting effect has been observed in a ferroelectric liquid crystal spatial light modulator (SLM). Used in transmission mode, with continuous read and write light illumination, the modulated read beam contains two modulations, one produced by the write beam intensity variation and the other produced by the electrical waveform used to drive the SLM. When a chopper is placed in the write beam and the chopping frequency is varied, yet another modulation of the read beam is observed. This modulation affects the contrast and resolution of the SLM, producing an output that sinusoidally varies between best contrast and resolution and no contrast or resolution. This modulation is due to synchronization of the frequency and phase of the electrical waveform driving the SLM. Results of an ongoing study of this effect and a theoretical model of the effect will be presented.
Direct imaging of surface diffusion by optical second harmonic microscopy
Authors: Seebauer E. G. , Schultz K. A. , Suni I. I. , Allen C. E.
Published: February 2023

The relaxation of a submonolayer step concentration profile of Sb on Ge(111) has been imaged directly by using a newly developed microscopy based on surface second harmonic generation. The step is created in ultrahigh vacuum near room temperature with a beam source and retractable mask. The sample is heated to the diffusion temperature (~800 K) so that the step relaxes. After quenching back to room temperature to freeze the profile, the entire profile is illuminated with a pulsed laser and the reflected second harmonic light is imaged into a photodiode array. SH yield vs. coverage is calibrated independently with Auger spectroscopy. Boltzmann-Matano analysis of the diffusion profile yields the coverage dependence of the diffusivity D. This method avoids the surface damage problems often associated with related laser desorption/grating techniques. We find that D decreases by an order of magnitude as the coverage increases, with a diffusional activation energy near 2 eV. The significance of these results for dopant incorporation chemistry in Ge molecular beam epitaxy is discussed.
Electro-optic sampling at zero propagation distance
Authors: Keil U. D. , Dykaar D. R.
Published: February 2023

Fast electrical pulses can be routinely generated with short pulse lasers and electro-optic sampling. We extend these techniques to allow measurement of an electrical pulse before any dispersion mechanisms can affect the pulse. We show that pulses ~250 fs FWHM (full width at half maximum) can be generated in semi-insulating GaAs and that 200 fs FWHM can be generated in low temperature grown GaAs.1 Previous results for undamaged silicon on sapphire were limited by transmission line dispersion to a rise time of 260 fs.2 System limited electrical rise times (10–90%) of ~145 fs and optical cross correlation (at the sample) of ~110 fs are measured. Short pulses are generated for both uniform and single electrode illumination.
Transient and sustained components of pupil responses evoked by spatial patterns
Authors: Young Rockefeller S. L. , Kennish Jessica
Published: February 2023

That human pupils react to changes in luminance, color, or form raises questions about how the retinal image is processed at the pretectal level. We report that pupil responses to spatial patterns, such as those to luminance or color, are composed of transient and sustained constriction components. Transiency and sustainedness are evidenced in the response waveforms to different spatial frequency gratings. Generally, the waveform is transient (at onset and offset) for 0.14 to 1.9 cpd gratings and sustained for 1.9 to 7.32 cpd gratings. Because the latency for high frequency responses is longer than that for low frequency responses of nearly identical amplitude, the responses are likely mediated by different processes. Furthermore, amplitude-contrast functions can be modelled as a linear sum of a process that saturates at low contrast and a process that varies linearly with contrast. The nonlinear process mostly accounts for results in low frequencies, whereas the linear process accounts for results in high frequencies. We conclude that pupillary constrictions evoked by spatial stimuli are mediated by magnolike and parvolike visual neurons.
Effects of aberrations on annular apodized beams
Authors: Strand T. C.
Published: February 2023

There has been considerable interest recently in beam apodization techniques for optical storage. This has been primarily aimed at decreasing the spot size to increase linear density. Although several people have shown that it is possible to achieve significant enhancements in the idealized case, very little has been done to look at the tolerance of these systems to departures from the ideal.
Recovering high density information from far field measurements
Authors: Marx David S. , Psaltis Demitri
Published: February 2023

We report the results of an experiment in which code words consisting of 0.1 μm lines are recorded on an optical storage medium and retrieved by using 633 nm wavelength illumination focused to a spot by a lens with numerical aperture equal to 0.7. The space-bandwidth product (the number of resolution elements) of this system is equal to unity. The information capacity of the system is determined by the space-bandwidth product and by the noise in the system. Using coding, we can increase the storage density up to the information capacity of the system. Sixty-three distinct code words are recorded in the memory, and the diffraction pattern for each code word is measured to form a template to classify future code words. To read from the memory, the diffraction pattern is measured repeatedly as the disk moves by 0.1 μm intervals. Since the illuminating spot is about 1 μm, each recorded bit is classified 10 times. The final assignment for each bit is by done by the majority rule or by Viterbi decoding. In our first experiment 90% of a test set of 560 bits were decoded correctly by using majority rule. We can use the measured error rate to obtain a lower bound of 2.5 bits per micrometer for the capacity.
Optical frequency division using a parametric oscillator
Authors: Wong N. C. , Lee D.
Published: February 2023

Frequency division in the optical regime is a desirable capability for precision measurement applications. We have recently demonstrated a new approach to tunable frequency division based on an optical parametric oscillator (OPO). By phase locking the signal–idler beat frequency to a microwave frequency source, an input pump frequency is halved. This beat frequency measurement precisely determines the signal and idler frequencies. The method is an efficient one-step process, and OPO dividers can be operated in series or in parallel to measure, compare, and synthesize frequencies from optical to microwave. Our initial results from a cw tunable KTP OPO divider indicate good frequency control and tuning capability, with a signal-idler beat-note linewidth at the hertz level. We will discuss the prospects for an OPO-based optical frequency counter that can accurately measure any optical frequency relative to a microwave frequency standard.
High-efficiency, Q-switched, mode-locked KTP OPO
Authors: Lowenthal Dennis D. , Miyake Charles , Cunningham Dave , Guyers Dean , Hamilton Charles , Braun Frank , Ewing J. J.
Published: February 2023

We have demonstrated an efficient, synchronously pumped, doubly resonant, KTP optical parametric oscillator (OPO). The efficiencies achieved are in excess of 60% for conversion to 2.128 μm by using a conventional mode-locked and Q-switched Nd:YAG 1.064-μm driver source. In some applications this device may be more attractive than directly using a 2.1-μm laser source. The quantum efficiency of the OPO is unity because it operates at the degenerate point (both the signal and idler waves have essentially the same wavelength at 2.128 μm), and both the signal and idler waves can be extracted to provide equally useful output power. Consequently, the overall conversion efficiency is equal to the photon conversion efficiency. Since the OPO is degenerate, it is also doubly resonant, but it does not suffer from the instability problems commonly associated with such devices. This is in part due to the large nonlinear drive, high output coupling (>95%), and simultaneous existence of many longitudinal modes. Normally, a degenerate OPO has a large frequency bandwidth. However, in KTP the phase matching must be type II, and this provides a narrow bandwidth at degeneracy of approximately 5 cm−1. This fact is extremely important for driving subsequent nonlinear stages. By using the 2-μm output power as a drive source, we have achieved frequency downconversion into the mid-IR in synchronously pumped AgGaSe2 OPO’s and we achieved 40% conversion of 2.128 μm to 3.8 plus 4.8 μm.
Comparison of motion aftereffect and motion fading with changes in stimulus parameters
Authors: Tripathy S. P. , Kew J. , Chen Y. , Bedell H. E.
Published: February 2023

The motion aftereffect (MAE) and motion fading (i.e., the perception that an eccentrically viewed moving target slows to a standstill after some time) both presumably represent the adaptation of motion mechanisms. If these phenomena are mediated by the same mechanisms, then their perceived magnitudes should change similarly with changes in stimulus parameters. We studied whether MAE duration and duration to motion fading change similarly as the retinal eccentricity and rotation speed of the stimulus are changed. Fading and MAE (with 1-min adaptation) durations were determined for a 2° diameter black-and-white annular disk rotating with speeds of 4–40 rpm (1–10 Hz). Measurements of durations for three normal observers were made at retinal eccentricities of 0°–20°. Both MAE and fading durations decreased with increasing eccentricity, but both phenomena could be elicited over only a small range of eccentricities (8–12°). When the stimulus size was spatially M-scaled to compensate for the variation of cortical magnification with eccentricity, both phenomena could be elicited at most eccentricities tested (2°–20°). Duration of both the MAE and motion fading generally increased with the speed of the stimulus (8 and 20 rpm), but neither varied systematically with eccentricity. The results suggest that the two phenomena are related.
Alternating electric field frequency influence on photorefractive characteristics
Authors: Brost George A. , Keefer Chris W.
Published: February 2023

The alternating electric field technique is attractive as it can significantly enhance the two-beam coupling gain over that of a dc field alone. In this paper we study the ac field frequency influence on the photorefractive characteristics. A finite difference technique was employed to numerically solve the material equations. These predictions are compared with experimental results for BSO crystals. We examine the frequency dependence of the magnitude of the space charge field as well as the temporal fluctuations in amplitude and phase. The frequency dependent characteristics are also found to be influenced by the modulation index.
Electromagnetic scattering from a conducting cylinder on a flat substrate: a study through the extinction theorem
Authors: Valle P. J. , Moreno F. , Gonzalez F. , Saiz J. M.
Published: February 2023

Boss models constitute an interesting method for studying the scattering of light by random rough surfaces. Different methods have been applied for studying the scattering of light by embossed surfaces for simple geometrical shapes (hemispheres, hemicylinders). More recently, theoretical treatments based on Maxwell's equations and image theory have been applied to surfaces constituted by spheres or cylinders on a flat substrate. The purpose of the present work is to analyze the scattering of light by a surface constituted by a conducting cylinder on a conducting flat substrate by means of the extinction theorem (ET). The analysis has been performed for different values of the ratio D/λ. (the cylinder diameter to the incident wavelength) ranging from 0.1 to 5 and for p and s polarizations (only one dimensional surfaces have been considered) under the approximation of perfect conductor. The current distribution on the surface, shadowing, and cavity effects that occur between the cylinder and the substrate because of multiple scattering have also been analyzed. Since the application of the ET requires scattering surfaces of finite length, the aforementioned analysis has been carried out by assuming an incident Gaussian beam to avoid edge effects. The generalization of the study to an embossed surface constituted by several parallel cylinders on the substrate to account exactly for multiple scattering between cylinders is currently being developed.
Unique hue judgments as a function of retinal eccentricity
Authors: Nerger Janice L. , Ayde Corey J. , Volbrecht Vicki J.
Published: February 2023

Unique hues were measured at the fovea and at 10° and 20° temporal eccentricities with stimuli of varying sizes to investigate the spatial limitations of the yellow-blue and red-green opponent processes. All stimuli were presented for 500 ms and eccentric measurements were made under conditions that eliminated rod contributions. For all three observers, compared to the fovea, unique green loci shifted to shorter wavelengths at 20°, with a greater shift for smaller stimuli. This is consistent with the eccentricity-dependent decline in S-cone density. For two observers, unique yellow showed no change with large test stimuli at 20°, as compared to the fovea, but it shifted to shorter wavelengths when test size was reduced. The third observer's unique yellow shifted to longer wavelengths relative to the fovea and shifted to shorter wavelengths with smaller test size. Preliminary data suggest that at 20° the minimum test size for unique yellow determinations is smaller than the minimum test size for unique green, thus indicating a difference in the spatial requirements of the two color-opponent systems. Measurements made in the nasal retina will also be reported.
Imaging characterization of short pulse electronic holography
Authors: Chen Ye
Published: February 2023

Imaging through biological tissue is a challenging problem of current scientific research. Recently, a technique combining short pulse or short coherence length illumination and electronic holographic gating was developed, and encouraging results were achieved with biological tissue imaging by using this method. To demonstrate its applicability to living tissue imaging, in particular, breast tissue imaging, further studies are being carried out. A model is established for the scattering properties of biological tissue. Based on this model, the point spread function is calculated for gating methods. The theoretical analysis shows that this method can be used for breast imaging with satisfactory resolution. To apply holographic gating to living tissue imaging, the characterization of both the stability and the time resolved properties of living tissue is necessary. Finally, the signal to noise ratio is evaluated for this imaging system, by using an object such as 1 cm thick biological tissue.
Imaging through scattering media and biological systems
Authors: Alfano R. R.
Published: February 2023

The transmission and imaging of ultrafast laser pulses through thick biological tissues and random media with translucent and opaque hidden objects are presented.
Characteristics of ferroelectric liquid crystal waveguide switches
Authors: Walker D. B. , Hartman N. F. , Glytsis E. N. , Gaylord T. K. , Handschy M. A.
Published: February 2023

The analysis, design, fabrication, and testing of ferroelectric liquid crystal (FLC) waveguides and waveguide switches are described. The TE, TM, and hybrid modes of propagation for waveguiding in the positive uniaxial FLC film are treated, including the effects of the indium tin oxide electrodes and silicon dioxide buffer layers. Grating coupling to the FLC waveguide is treated and, design for maximum diffraction efficiency is obtained. Two basic types of switch/modulator devices in single-mode waveguides are as follows: 1) cutoff (on-off) attenuation modulator and 2) deflection modulator. In both cases the modulation is produced by electrically switching the optic axis of the FLC by 45°. In the on-off modulator, this causes the propagating mode to be cut off and thus strongly attenuated. In the deflection modulator, this causes a change in the mode index, and thus the output coupled light is deflected through the grating to a new angle. The effects of attenuation in the FLC are included in this work.
New autocorrelation method for computing diffraction OTF
Authors: Stamnes Jakob J.
Published: February 2023

The standard autocorrelation method for computing the diffraction optical transfer function (OTF) of optical systems is based on the existence of a Fourier-transform relationship between the field in the exit pupil and the field in the observation plane. Since this relationship holds only in the small-angle approximation, a new autocorrelation method is developed that holds exactly within the Kirchhoff approximation. While the standard method involves the autocorrelation of the field in the exit pupil, the new method involves the autocorrelation of the Fourier transform of the field in the observation plane. The practical implementation of the new method is also discussed. It involves ray tracing to compute the amplitude and the wave front in the exit pupil and an efficient method for computing the autocorrelation integral.
Quasiclassical approximation in cavity quantum electrodynamics
Authors: Gea-Banacloche J.
Published: February 2023

Many field states in quantum optics may be regarded as quasiclassical in that they possess a fairly well-defined phase and amplitude in the limit in which the average number of photons is large. Examples include coherent states and squeezed states that have a coherent component substantially larger than the squeezed noise contribution. For such states, calculations involving sums over the coefficients in the Fock-state basis can be considerably simplified in the limit of large photon number. The Jaynes-Cummings model and its extensions (to, e.g., three-level, two-mode configurations) may be advantageously studied from this perspective. New results on the three-level, two-mode problems, on the influence of cavity losses, and on the various time scales of interest will be presented here. The method typically identifies a set of privileged, long-lived atomic states, which lead to a quasiclassical evolution that agrees with the prediction of semiclassical treatments over a characteristic time scale; linear combinations of the long-lived states, on the other hand, become superpositions of macroscopically distinct states in time and result in an evolution that exhibits many uniquely quantum effects.
Cavity quantum electrodynamics with a small number of atoms
Authors: Alsing P. M. , Savage C. M.
Published: February 2023

With the aid of supercomputer models we numerically investigate the exact solutions for a small number of atoms (typically 1–10) interacting with a single quantized mode of an electromagnetic cavity that is driven by an external coherent field. Effects of spontaneous emission and a nonzero cavity decay rate are included. We investigate the strong coupling regime where the atom-field coupling constant is much greater than the dissipation rates to the external environment. In this regime, the usual system size expansions of quantum statistical physics are not applicable and a full numerical solution is required. We model the recently reported experimental observations of Rabi oscillations in the second order coherence function1 g(2)(τ) and compare and contrast the results with an effective single atom-cavity model with an appropriately scaled coupling constant. In addition, the steady state field distribution for the few-atom-cavity system is explored. A multipeaked phase distribution is found that generalizes the bimodal phase distribution found in the single-atom-cavity case.2 Spectra for the few-atom-cavity system are investigated in the weak and strong driving field limits.
Acousto-optical bistability in the second Bragg regime
Authors: McNeill M.D. , Poon T.-C.
Published: February 2023

Previous research with acousto-optic hybrid optical/electronic (HOE) bistable devices has been directed towards operation in the first Bragg regime.1 We have demonstrated several simulations and experiments to study a HOE bistable system in the second Bragg regime. In this bistable system, the acousto-optic device operates in the second order with the light incident at twice the Bragg angle. To achieve optical bistability, the second order diffracted light is detected by a photodetector, amplified with a linear amplifier, summed with a bias voltage, and feedback to the acousto-optic device. The operation of the acousto-optic device can be explained by a set of coupled differential equations. Likewise, the feedback loop can be modeled with a feedback equation. The simultaneous solution of these equations provided our theoretical model. In this talk, we will compare theoretical and experimental results, as well as compare first order and second order operation.
Optical bistability and hysteresis with a photorefractive self-pumped ring phase conjugate resonator
Authors: Chen Bo Su , Venkateswarlu Putcha
Published: February 2023

Optical bistability and hysteresis in BaTiO3 have been observed in a self-pumped ring resonator (SPRR). The SPRR can be controlled with an additional He–Ne laser erasing beam that makes an angle with the ring pump beam. The erasing beam could be coherent or incoherent with the pump beam. By injecting the erasing beam into the crystal in such a way as to partially erase the index grating and/or take energy from the pump beam, the coupling strength is modified. In either case, the output of the ring shows bistability and hystersis in the complete cycle of the on-off-on operation by monitoring the intensity of the erasing beam. The intensity change and the time interval between each change step of the erasing beam have effects on the hysteresis behavior. The hysteresis observed when it is controlled by a coherent erasing beam is more than the one by an incoherent erasing beam. Some fluctuations exist in the hysteresis loop when the coherent erasing beam is used.
Applications of heterodyning for measuring photoelasticity coefficients
Authors: Yang Xuan-Min , Yi Ming , Kou Guo , Wu Xing-Long
Published: February 2023

Usually, the elasto-optical coefficients p11, p12,… have to be measured by an optical birefringence interference method associated with an ultrasonic method. By using a laser heterodyning method, one could measure the variations in optical path differences very precisely. Therefore, the variations in the refractive index Δn
e
and Δno of K-9 glass under 1 atm pressure have been measured directly and precisely to the order of 10–7. Then the elasto-optical coefficients p11, p12,… have been obtained directly. This technique is very useful for evaluating some kinds of lens design, for instance, the variations of refractive index of a telescope caused by its weight. The dynamic process, the curve of Δn
e
and Δn
o
via stress, has also been obtained. It shows some interesting results.
Gray scale correlation with a real-time AO correlator: experimental results
Authors: Kast B. A. , Dickey F. M. , Yee M. L.
Published: February 2023

Real-time correlation in the spatial domain has been demonstrated previously by using an acousto-optical (AO) correlator. This acousto-optic system performs correlations at high frame rates, which permits the implementation of real-time pattern recognition algorithms that use multiple templates. Previous work has been done with edge-enhanced templates and images, by using binary rather than full gray-scale pixels. The present work shows the ability of the AO correlator to process gray-scale imagery for the purpose of implementing the classical matched filter. Since intensity invariance is an issue with gray-scale imagery, normalized correlation is implemented on the AO correlator. Experimental results obtained by using real gray-scale imagery are presented.
Applications of ultrafast laser diodes
Authors: Delfyett Peter J. , Florez L. T. , Silberberg Y. , Hartman D. H. , Alphonse G. A.
Published: February 2023

Semiconductor lasers may play an important role in future photonic telecommunication switching networks. By mode-locking these semiconductor laser devices, compact and efficient sources become available for use in future photonic networks, ultrafast diagnostics, and high speed instrumentation. This talk presents recent results on the generation and application of high power ultrashort optical pulses from semiconductor laser diodes. The pulse duration and peak power of the generated optical pulses are 207 fs and 165 W, respectively, making these pulses both the shortest and most intense ever generated from an all semiconductor diode laser system. Applications of these high power optical pulses include ultrafast spectroscopy, where the nonlinear gain dynamics of the amplification process in traveling wave amplifiers have been investigated by using standard time resolved pump-probe techniques. Other applications utilizing these high power optical pulses will also be discussed, with an emphasis on optical clock distribution and network synchronization for SONET networks, high speed switching systems, and supercomputers.
Experiments in kinematic mode locking
Authors: Bernardin J. P. , Lawandy N. M.
Published: February 2023

We report new experimental results on a coupled cavity moving mirror ring dye laser operating with a repetition rate of 250 MHz. Existing published models for the mode-locking mechanism are analyzed in light of the various experiments performed in this study. We find thresholds for the onset and instability of kinematic mode locking (KML) as a function of pump power. The pulse length dependence on mirror velocity and cavity detuning are found as well as mirror velocity asymmetries. We show that the multimode noise manifested in the width of the cavity beat note at 250 MHz appears to be but is, in fact, not correlated with the required mirror velocities for mode locking, as previous models have conjectured. A prism pair is added to the external cavity for group velocity dispersion compensation, which with proper adjustments can also tune the laser over the entire rhodamine 6G bandwidth. With the inclusions of prisms, the mode locking is found to be more stable and pulses shorter than 3 ps are obtained.
Applications of a skew ray matrix formalism to problems exceeding the paraxial ray limit
Authors: Collins Stuart A.
Published: February 2023

This paper contains a discussion of the application of the skew ray matrix formalism and the ray matrix diffraction integral1 to problems where the paraxial ray limit is exceeded or where the rays and fields are expanded about a base ray that makes a large angle with the optical axis. One example is the point response function for fields around a large angle skew ray. Another example is the diffraction of patterns with detail so small that diffracted rays make excessively large angles. In such a case the angular region must be divided into regions where the small angle approximation applies.
Anisotropies in depth thresholds of spatial patterns?
Authors: Davis Elizabeth T. , King Robert A. , Guenter Brian , Anoskey Alana
Published: February 2023

Stereopsis can provide essential depth information for recognizing objects and determining their spatial layout. Although some processing components are unique to stereopsis, lower monocular visual components can also affect stereopsis. For instance, we found an oblique effect for depth threshold, analogous to some monocular oblique effects. Are explanations of the stereo-oblique effect different from, or similar to, those of oblique effects for monocular vision? We used several experimental conditions to examine possible explanations as to why depth thresholds are larger for oblique patterns than for vertical ones. Possible explanations include (1) sparseness of horizontal disparities resulting from (a) shrinkage of vertical extent or (b) stretching of horizontal extent in oblique patterns; (2) introduction of vertical disparities in oblique patterns; and (3) the "stereo aperture problem" (viz. only disparities perpendicular to the pattern's orientation are encoded). While sparseness of horizontal disparity information may explain a small part of the oblique effect, the stereo aperture problem can account for most of it. We will discuss the implications of our results in terms of models of human stereopsis and the design of stereoscopic displays.
Beam quality in high-power visible-region diode lasers
Authors: Tatum Jim A. , Strozewski Roman , Serreze Harvey B. , MacFarlane Duncan L.
Published: February 2023

Applications of visible diode lasers such as laser pumping, plastic
fiber optics, optical storage, and laser printing rely on the ability
to control the spatial profile and precise positioning of laser
radiation.
Portable infrared camera
Authors: Laband Stan
Published: February 2023

The 256×256 element MWIR detector array construction is based on hybrid focal plane array (FPA) technology.
Optical beam smoothing on the NIKE KrF laser
Authors: Lehmberg R. H. , Pawley C. J. , Obenschain S. P. , Pronko M. S. , Deniz A. V. , Lehecka T.
Published: February 2023

One of the key requirements for direct-drive laser fusion is a focal profile that is sufficiently smooth and controllable to produce highly symmetric implosions.
Optical preprocessing for pattern-recognition systems
Authors: Hsu Ken Y. , Gruber Matthias U.
Published: February 2023

It is a principal problem in pattern recognition to satisfy the highly contradictory requirements of inter-class discrimination and intra-class invariance.
Experimental comparison of different apodizers for minimizing diffraction rings in 1.06-μm laser fusion system
Authors: Lukishova S.G. , Bykovsky N.E. , Poletimov A.E. , Scheulin A.S.
Published: February 2023

Among different types of apodizers which minimize diffraction rings, the most widespread in inertial confinement fusion systems for our knowledge are following: periodically modulated tooth [1], sandblasted [2], liquid crystal [3] apertures.
Superdriven two-level atom: generation of very-high-order harmonics and combination frequencies
Authors: Kaplan A. E. , Shkolnikov P. L.
Published: February 2023

Very high harmonic generation (HHG) by intense optical laser in rare gasses has recently been observed [1] in experiment.
High harmonic generation in atomic gases with eliptically polarized light
Authors: Burnett N.H. , Corkum P.B.
Published: February 2023

There is much current interest in the generation of high harmonics (N > 25) in atomic gases when irradiated at intensities near threshold for multiphoton ionization.
Anisotropic velocity dependent vortex forces
Authors: Cai Tianwu , Bigelow N. P.
Published: February 2023

There has been considerable interest in the force on an atom in a two-dimensional light field.
Parallel image transmission via multimode fiber-photorefractive crystal system using phase conjugation
Authors: Kukhtarev N. , Caulfield H. J. , Chen Bo Su , Volyar A. , Gnatovskii A.
Published: February 2023

We report some new results in parallel image transmission via 2-meter multimode fiber (core diameter 70 μm, N.A. 0.17), using polarization preserving phase conjugation in the photorefractive crystal LiNbO3 Fe.
Modulation spectroscopy of a cavity-QED system
Authors: Tian L. , Carmichael H. J.
Published: February 2023

Cavity QED experiments in the optical domain have been successful in making direct spectroscopic observations of the normal-mode splitting of an induced atomic polarization coupled to a cavity mode (“vacuum” Rabi splitting).
Suppression of absorption due to the effects of polarization dependence in cavity TPA
Authors: Schauer Daniel L.
Published: February 2023

Recent work has shown that introducing polarization dependent processes to two-photon absorption leads to interesting behavior of the radiation field.1
Microspacecraft optical instruments
Authors: Chrisp Michael P.
Published: February 2023

Microspacecraft require remote sensing optical instruments that are an order of magnitude lighter than the instruments used in the past.
Regenerative pulsations and transverse structures in bulk ZnSe
Authors: St. John W. D. , Wicksted J. P.
Published: February 2023

Experimental and theoretical results of absorptive optical bistability in bulk ZnSe will be presented.
Macular pigment densities in monozygotic twins
Authors: Hammond Billy R. , Fuld Kenneth , Curran-Celentano Joanne
Published: February 2023

Measurements of macular pigment (MP) typically show wide variation among individuals.
Visual processing of simple and multiple motion components
Authors: Sachtler W. L. , Zaidi Qasim
Published: February 2023

Sensitivity to shearing and cohesive motion was measured for briefly presented pairs of contiguous sinusoidal gratings.
Generation and application of hard-x-ray picosecond pulses by an optically driven x-ray diode
Authors: Tomov I. V. , Rentzepis P. M.
Published: February 2023

Generation of hard x-ray pulses in the range 10-100 ps has been achieved by driving a vacuum photodiode with 193 nm picosecond light pulses in order to maximize the photo emission from metallic cathodes.
Turn-on jitter of semiconductor lasers subject to weak optical feedback in short external cavities
Authors: Hernandez-Garcia E. , Mirasso C.R. , Shore K.A. , San Miguel M.
Published: February 2023

Turn-on delay jitter is of considerable importance for practical applications of semiconductor lasers.
An injection-locked AlGalnP amplifier at 647.1 nm
Authors: Andrews John R. , Bour David P. , Treat David W.
Published: February 2023

Xerox Palo Alto Research Center. Injection locking has proven a useful means to obtain high power spatially coherent beams in broad area AlGaAs infrared lasers. We have applied the injection locking technique to AlGalnP broad area visible lasers in order to amplify the 647.1 nm line of a krypton ion laser. The AlGalnP laser was 200 pm wide by 750 pm long with uncoated facets. The threshold current density at room temperature was 300 A/cm2. The laser amplifier was operated p-side up with 600 ns pulses at 10 kHz. Light was coupled into the amplifier by focusing perpendicularly to the junction and collimating parallel to the junction. The exiting amplified beam had a divergence that was essentially diffraction-limited at 0.18* when the aperture was overfilled and and increasing to 0.22° when the amplifier aperture was underfilled in order to maximize the gain. A maximum single lobe of 167 mW pulsed at a gain of 8.1 dB was obtained at 3.2 times threshold. A maximum gain of 12.1 dB overall was obtained with 46 mW pulsed in a near diffraction-limited single lobe at 3.2 times threshold. Pulsed current operation lead to temporal pulse shape distortion. Further improvements in amplifier operation might be expected from cw injection locking and from traveling wave amplification.
Comparison of Losses in Glass Waveguides Made by Different Ion-Exchange Processes
Authors: Wang Wei-Jian , Honkanen Seppo , Najafi S. Iraj , Tervonen Ari
Published: February 2023

The studied waveguides arc 1) one-step aluminum masked silver ion-exchanged waveguide, 2) silver ion-exchanged waveguide made with dielectric mask (ionic masking) and 3) several potassium and silver double-ion-exchanged waveguides made with aluminum mask.
Planar optical waveguides made by ionic exchange in new fluoride glasses
Authors: Charron C. , Fonteneau G. , Rimet R. , Lucas J.
Published: February 2023

Many laboratories are interested in integrated optics on active glasses, espe­cially phosphate and silicate glasses.
The virtual instrument: end-to-end modeling of optical systems
Authors: Redding Dave
Published: February 2023

Summary not available.
Compact, high-gain fusion-laser preamplifier using multipass amplifiers and flexible beam shaping
Authors: Van Wonterghem B.M. , Norman M. , Speck D.R. , Wilcox R. B.
Published: February 2023

This contribution describes the amplifier and beam shaping section of a new pulse generation system that will drive the Beamlet laser at LLNL.
Highly reliable, stable, and synchronizable longpulse monomode oscillator for laser fusion drivers
Authors: Seka W. , Will I. , Chow J. , Brown D. L. , Skeldon M. D. , Merle C. K. , Roides R. G. , Ragg W.
Published: February 2023

We report on a reliable, hands-off, externally triggerable, Q-switched Nd:YLF monomode oscillator at 1053 nm.
1-D beam-steered shadow-casting correlator
Authors: Raj K. , Athale R. A. , Mait J. N. , Prather D. W.
Published: February 2023

Recently a beam steered shadow-casting correlator was proposed [1].
Color appearance under chromatic adaptation varied along theoretically significant directions in color space
Authors: Wei Jianping , Shevell Steven K.
Published: February 2023

We measured changes in color appearance caused by chromatic adaptation.
Scalar and vector self-diffraction and phase conjugation with polarization restoration in disodium fluorescein thin films
Authors: Kukhtarev N. , Henry M. , Abdeldayem H. , Venkateswarlu P.
Published: February 2023

Polarization preserving phase conjugation (PC) was shown to be important for a fundamental communication problem: two-dimensional image transmission via multimode fiber [1,2].
Strong photothermal deflection in a highly absorbing medium
Authors: Misra Raj M. , Banerjee Partha P.
Published: February 2023

We study photothermal deflection1 of a probe beam due to pump-probe interaction in a highly absorbing medium.
EPR evidence of photoinduced charge transfer and photoconductivity in Fe3+:BaTiO3 illuminated with a He-Ne laser
Authors: Moghbel M. , Sastry M. D. , Venkateswarlu P. , Jeevarajan A. S. , Kispert L. D.
Published: February 2023

With a view to understanding the microscopic origin of photorefractive effect in Fe doped BaTiO3, electron paramagnetic resonance (EPR) studies were conducted during laser illumination.
Photorefractive properties of a-axis Ce:SBN60 single crystal fibers
Authors: Sugiyama Yasuyuki , Yagi Shogo , Hatakeyama Iwao
Published: February 2023

Fiber type photorefractive crystals are attractive in that they provide both strong optical field confinement which reduces the required light source power and a longer interaction length which allows high angular selectivity in holographic multiplex recording?
Trends in fiber-optic beam delivery for materials processing
Authors: Kugler Thomas R.
Published: February 2023

The initial application of fiber optic delivery to materials processing can be traced back to the early 1980s.
How to use optical Fourier transform systems in engineering education
Authors: van der Gracht Joseph
Published: February 2023

Optical Fourier transforming systems are useful tools for teaching Fourier analysis and synthesis to undergraduate electrical engineering students.
Volume holographic optical interconnects using irregular patterns
Authors: Jin Sang Kyu , Lee Hyuk
Published: February 2023

Volume holographic interconnections using photorefractive crystal have been proved to be important in implementing high capacity neural networks.1
Optically interconnected MCM’s for asynchronous-transfer-mode networks
Authors: Kiamilev Fouad , Sharma Rohini , Childers John , Morris Jim , Yang Hedong , Feldman Mike
Published: February 2023

Asynchronous transfer mode (ATM) is a switching technique that can be used in wide and local area computer networks.
Optical back-action-evading measurement with a parametric amplifier
Authors: Pereira S. F. , Ou Z. Y. , Kimble H. J.
Published: February 2023

In quantum mechanics, the act of measurement perturbs the system by adding noise that usually contaminates subsequent measurements of the observable in question.
Ultrafast time and spatial gated optical imaging in biomedical media
Authors: Ho P. P. , Wang L. , Liang X. , Galland P. , Kalpaxis L. , Alfano R. R.
Published: February 2023

Imaging of hidden objects located inside high scattering biomedical media using light is one of the most challenging problems in optics.
Semiconductor ring lasers
Authors: Hohimer J. P. , Vawter G. A.
Published: February 2023

Ring cavities have led to enhanced performance in many types of lasers. We are investigating circularcavity semiconductor ring lasers both to understand the behavior of this new class of diode lasers, and to develop new and unique types of direct-waveguide-coupled laser sources for photonic integrated circuits.