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Results for “acousto-optic”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Low-phase-noise surface-acoustic-wave oscillator using an edge mode of a phononic band gap

Low-phase-noise microwave-frequency integrated oscillators provide compact solutions for various applications in signal processing, communications, and sensing. Surface acoustic waves (SAWs), featuring orders-of-magnitude shorter wavelength than electromagnetic waves at the same frequency, enable integrated microwave-frequency systems with much smaller footprint on chip. SAW devices also allow higher-quality (Q) factors than electronic components at room temperature. Here, we demonstrate a low-phase-noise gigahertz-frequency SAW oscillator on 128°Y-cut lithium niobate, where the SAW resonator occupies a footprint of 0.05 mm 2 . Leveraging phononic crystal band-gap-edge modes to balance between Q factors and insertion losses, our 1-GHz SAW oscillator features a low phase noise of -132.5 dBc/Hz at a 10-kHz offset frequency and an overlapping Hadamard deviation of 6.5 × 10 -10 at an analysis time of 64 ms. The SAW resonator-based oscillator holds high potential in developing low-noise sensors and acousto-optic integrated circuits.

42 ENGINEERING↗
DOE OSTI2025

Spectral broadening and pulse shaping in the deep ultraviolet

Here, we report the generation and shaping of ∼20 femtosecond pulses in the deep ultraviolet (DUV). Our approach combines spectral broadening in a stretched hollow-core fiber with compression and shaping via an acousto-optic modulator-based pulse shaper. The pulse shaper allows for automatic compression, useful for in-air delivery of pulses to two-dimensional (2D) spectroscopy and other time-resolved experiments. Unlike previous DUV pulse generation schemes that lack phase stability, our method enables programmable generation of phase-locked pulse-pairs with attosecond-level stability. We demonstrate pulse characterization via self-diffraction frequency-resolved optical gating and dispersion scan methods in the DUV and validate performance through a pump-probe experiment resolving electronic dynamics on attosecond timescales.

Codere, Julia [Stony Brook Univ., NY (United State↗
DOE OSTI2026

Measurement of the QE Map

113 MHz SRF gun utilized CsK 2 Sb and Na 2 KSb cathodes, which were irradiated with a pulsed green laser with a wavelength of 0.53 microns. The drive laser generated 78 kHz pulses with an acousto-optic modulator selecting the desired number of pulses reaching the cathode. The operator can select the aperture size, defining the laser spot diameter on the cathode, and the power level, which is controlled by a rotating polarizer. The laser power reaching the cathode can be measured with a meter based on a photodiode. The quantum efficiency (QE) of a photocathode serves as a primary indicator of its state. Small QE renders the cathode unusable when the desired bunch charge cannot be achieved. Strong variations in the quantum efficiency on the cathode surface might lead to the growth of the beam emittance due to the space charge effects. We have created a routine to measure the distribution of the QE on the cathode. The operator selects the aperture size, the central spot location, and the scan ranges for both planes. The scan starts from the central spots and proceeds along a spiral-like trajectory, making N rounds. The number of rounds can be chosen, and the total number of measured points is (2N+1) 2 . The laser spot movement is shown in Fig. 1.

43 PARTICLE ACCELERATORS↗
NASA NTRS1973

Materials sciences research

Research projects involving materials research conducted by various international test facilities are reported. Much of the materials research is classified in the following areas: (1) acousto-optic, acousto-electric, and ultrasonic research, (2) research for elucidating transport phenomena in well characterized oxides, (3) research in semiconductor materials and semiconductor devices, (4) the study of interfaces and interfacial phenomena, and (5) materials research relevant to natural resources. Descriptions of the individual research programs are listed alphabetically by the name of the author and show all personnel involved, resulting publications, and associated meeting speeches.

Source record↗
NASA NTRS1974

On the ultrasonic holography

The development of a system of ultrasonic holography is discussed. The limitations of the acousto-optical transformers, the scanning method, and the Pohlman cell are analyzed. The application of the free liquid surface deformation method is emphasized. The test equipment required for the liquid surface deformation method is described. An illustration of a typical test installation is provided.

Zieniuk, J. K.↗
NASA NTRS1975

A coherent light scanner for optical processing of large format transparencies

A laser scanner is discussed in which the scanning beam is random-access addressable and perpendicular to the image input plane and the irradiance of the scanned beam is controlled so that a constant average irradiance is maintained after passage through the image plane. The scanner's optical system and design are described, and its performance is evaluated. It is noted that with this scanner, data in the form of large-format transparencies can be processed without the expense, space, maintenance, and precautions attendant to the operation of a high-power laser with large-aperture collimating optics. It is shown that the scanned format as well as the diameter of the scanning beam may be increased by simple design modifications and that higher scan rates can be achieved at the expense of resolution by employing acousto-optic deflectors with different relay optics.

Callen, W. R.↗
NASA NTRS1977

A laser scanner for 35mm film

The design, construction, and testing of a laser scanning system is described. The scanner was designed to deliver a scanned beam over a 2.54 cm by 2.54 cm or a 5.08 cm by 5.08 cm format. In order to achieve a scan resolution and rate comparable to that of standard television, an acousto-optic deflector was used for one axis of the scan, and a light deflecting galvanometer for deflection along the other axis. The acoustic optic deflector has the capability of random access scan controlled by a digital computer.

Callen, W. R.↗
NASA NTRS1978

Optical signal processing

The article discusses several optical configurations used for signal processing. Electronic-to-optical transducers are outlined, noting fixed window transducers and moving window acousto-optic transducers. Folded spectrum techniques are considered, with reference to wideband RF signal analysis, fetal electroencephalogram analysis, engine vibration analysis, signal buried in noise, and spatial filtering. Various methods for radar signal processing are described, such as phased-array antennas, the optical processing of phased-array data, pulsed Doppler and FM radar systems, a multichannel one-dimensional optical correlator, correlations with long coded waveforms, and Doppler signal processing. Means for noncoherent optical signal processing are noted, including an optical correlator for speech recognition and a noncoherent optical correlator.

Casasent, D.↗
NASA NTRS1980

Optical mass memory investigation

The MASTER 1 optical mass storage system advanced working model (AWM) was designed to demonstrate recording and playback of imagery data and to enable quantitative data to be derived as to the statistical distribution of raw errors experienced through the system. The AWM consists of two subsystems, the recorder and storage and retrieval. The recorder subsystem utilizes key technologies such as an acoustic travelling wave lens to achieve recording of digital data on fiche at a rate of 30 Mbits/sec, whereas the storage and retrieval reproducer subsystem utilizes a less complex optical system that employs an acousto-optical beam deflector to achieve data readout at a 5 Mbits/sec rate. The system has the built in capability for detecting and collecting error statistics. The recorder and storage and retrieval subsystems operate independent of one another and are each constructed in modular form with each module performing independent functions. The operation of each module and its interface to other modules is controlled by one controller for both subsystems.

Source record↗
NASA NTRS1981

Optical implementation of systolic array processing

Algorithms for matrix vector multiplication are implemented using acousto-optic cells for multiplication and input data transfer and using charge coupled devices detector arrays for accumulation and output of the results. No two dimensional matrix mask is required; matrix changes are implemented electronically. A system for multiplying a 50 component nonnegative real vector by a 50 by 50 nonnegative real matrix is described. Modifications for bipolar real and complex valued processing are possible, as are extensions to matrix-matrix multiplication and multiplication of a vector by multiple matrices.

Caulfield, H. J.↗
NASA NTRS1981

Matrix vector multiplier with time varying single dimensional spatial light modulators

The applicability of iterative optical processors in environments requiring a short transient response time is analyzed. An approach is proposed utilizing acousto-optic single dimension light modulators where the matrix is the outer product of two vectors. The problems associated with a nonnegative real representation are addressed. A solution is proposed at some cost of processor speed.

Tarasevich, A.↗
NASA NTRS1981

Optical Spatial integration methods for ambiguity function generation

A coherent optical spatial integration approach to ambiguity function generation is described. It uses one dimensional acousto-optic Bragg cells as input tranducers in conjunction with a space variant linear phase shifter, a passive optical element, to generate the two dimensional ambiguity function in one exposure. Results of a real time implementation of this system are shown.

Tamura, P. N.↗
NASA NTRS1981

The integrated optic RF spectrum analyzer

The results of measurements made on a fully integrated optic RF spectrum analyzer (IOSA) are reported. The performance of the device acousto-optic bandwidth, single-tone RF resolution, two-tone RF resolution, single-tone dynamic range, two-tone dynamic range, and single-tone RF response are presented. The device parameters that control device performance are analyzed. These results demonstrate the viability of the IOSA for real time spectrum analysis of pulsed and CW RF signals. Improvements of RF bandwidth resolution can be obtained by the use of larger collimated optical beams which requires larger optical lens elements, and hence, larger crystals.

Pedinoff, M. E.↗
NASA NTRS1981

Imaging spectroscopy; Proceedings of the Seminar, Los Angeles, CA, February 10, 11, 1981

The seminar concentrated on the science applications of spectral imaging, multispectral imaging sensors, and spectral filtering. Papers are presented on spectroscopic remote sensing for geological applications, spectral mapping of Jupiter, system design of an interferometer imaging sounder and a common module imaging spectral radiometer. Other topics discussed include the performance and application of an intensified linear self-scanned array instrument, tunable optical filtering using an interferometer for selective modulation, design studies for a spectrally agile staring sensor system, and acousto-optic tunable filters for high-resolution spectral analysis.

Norris, D. D.↗
NASA NTRS1982

Preliminary submillimeter spectroscopic measurements using a submillimeter heterodyne radiometer

A submillimeter heterodyne radiometer uses a submillimeter laser, pumped by a CO2 laser, as a local oscillator and a room temperature Schottky barrier diode as the first IF mixer. The radiometer can resolve spectral lines in the submillimeter region of the spectrum (arising from pure rotational molecular transitions) to within 0.3 MHz, using acousto-optic spectrum analyzer which measures the power spectrum by simultaneously sampling 0.3 MHz wide channels over a 100 MHz bandwidth spanning the line. Preliminary observations of eight spectral lines of H2O2, CO, NH3 and H2O, all lying in the 434-524 micrometer wavelength range are described. All eight lines were observed using two local oscillator frequencies obtained by operating the submillimeter laser with either methyl fluoride (CH3F) or formic acid (HCOOH) as the lasing gas. Sample calculations of line parameters from the observed data show good agreement with established values. One development goal is the size and weight reduction of the package to make it suitable for balloon or shuttle experiments to detect trace gases in the upper atmosphere.

Safren, H. G.↗
NASA NTRS1981

Infrared astronomy - Scientific/military thrusts and instrumentation; Proceedings of the Meeting, Washington, DC, April 21, 22, 1981

A series of papers on infrared astronomy is presented. Among the topics discussed are those concerning programs, such as NASA's planning, the Cosmic Background Explorer and a cryogenic infrared radiance instrument for the Space Shuttle. Articles on infrared astronomy technology include those on an infrared camera for 10-micron astronomy, bulk and integrated acousto-optic spectrometers for molecular astronomy with heterodyne spectrometers, and airborne measurements of infrared atmospheric radiance and sky noise. Several papers on infrared astronomy spectroscopy are included, such as infrared heterodyne spectroscopy and infrared lines from shocked galactic gases. Among the articles on infrared astronomy catalogues and operations are discussions of groundbased infrared measurements using the AMOS/MOTIF facility and the prediction of infrared celestial source counts.

Boggess, N. W.↗