Method of directing a laser beam with very high accuracy
System will collimate and direct an argon laser beam with high angular tracking accuracy at objects on the moons surface. It can be adapted to missile and satellite tracking.
Allen, L. H.↗
SEARCH · Engineering Papers
Results for “Laser beams”
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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Interaction of high-powered focused laser beam with exploding wire.
Exploding wire heating technique using combination of focused laser beam electric field intensity and pulsed power electric current
Davis, P. W.↗
A Fuzzy Logic Based Controller for the Automated Alignment of a Laser-beam-smoothing Spatial Filter
A fuzzy logic based controller for a laser-beam-smoothing spatial filter is described. It is demonstrated that a human operator's alignment actions can easily be described by a system of fuzzy rules of inference. The final configuration uses inexpensive, off-the-shelf hardware and allows for a compact, readily implemented embedded control system.
Krasowski, M. J.↗
Simulated effect of defect volume and location on very high cycle fatigue of laser beam powder bed fused AlSi10Mg
This study quantifies the interaction between volumetric defect location and size on the very high cycle fatigue (VHCF) of laser beam powder bed fused (LB-PBF) AlSi10Mg. Crystal plasticity finite element method (CPFEM) simulations were used to investigate the effects of defect location and size on the driving force for crack initiation. The CPFEM model was calibrated against uniaxial and cyclic experimental data of LB-PBF AlSi10Mg. Defect characteristics were informed by experimental data from the specimens produced in various geometries to create realistic representative volume elements (RVEs) with equivalent volume fractions of defects. By embedding defects of varying sizes and locations within the RVEs, fatigue indicator parameters (FIPs) were calculated to analyze the impact of defects’ characteristics on fatigue performance. Different combinations of defect volume and locations were generated for various microstructure instantiations, providing insight into extreme value fatigue responses. Larger defect volumes located on free surfaces consistently generated the highest FIPs, suggesting defect size and boundary proximity intensify stress concentration effects. RVEs with multiple smaller defects produced lower FIPs than those with single large critical defects. These findings underscore the critical role of defect characteristics on fatigue life, providing a foundation for future predictive modeling in fatigue-sensitive AM applications.
AlSi10Mg↗
Focused laser-beam experiment and the oscillator strength of the swan system.
Q-spoiled ruby laser beam focused on graphite, obtaining Swan emission of carbon molecule
RUBY LASER↗
Fast spatial laser beam modulation for improved process control in Laser Powder Bed Fusion
Not Available
Tumkur, Thejaswi U.↗
Improving laser beam coherence - A concept
Laser frequencies may be reduced to single frequency or selected frequencies. For single frequency performance, spacing of frequencies falls in natural line width. For two or more frequencies, thicker spacing is used. Configuration adapts to operation with Kerr or Pockel cell for Q switching.
Heflinger, L. O.↗
An active alignment method for post launch co-alignment of laser beam combiner systems
A laser transmitter for high bandwidth geosynchronous satellite communications is described. High optical power is achieved by combining semiconductor laser diodes. An active alignment scheme is proposed for achieving the +/- 20 microrad post launch multiple laser angular co-alignment requirement.
Yu, A. W.↗
Laser beam modeling in optical storage systems
A computer model has been developed that simulates light propagating through an optical data storage system. A model of a laser beam that originates at a laser diode, propagates through an optical system, interacts with a optical disk, reflects back from the optical disk into the system, and propagates to data and servo detectors is discussed.
Treptau, J. P.↗
Generation of Bright Soft X-ray Laser Beams (Final Report)
The project goal was to demonstrate new compact soft x-ray lasers emitting high energy ultrashort pulses at shorter wavelengths and increased repetition rates by amplification in atomic transitions in high density laser-created plasmas. To demonstrate these lasers we developed new high power solid state lasers. The project succeeded in demonstrating the shortest wavelength compact soft x-ray laser to date, 6.85 nm wavelength, and the highest repetition rate table-top soft x-ray laser, 400 Hz. We also applied these compact soft x-ray laser sources to determine the composition of materials with nanoscale resolution using a new technique that combines soft x-ray laser ablation with mass spectrometry, and we demonstrated that these lasers are capable of acquiring nanoscale resolution holograms with picosecond time resolution. The combination of an increased pumping efficiency with increased repetition rates can yield soft x-ray laser beams with an unprecedented average power on a table-top for applications demanding a high photon flux. We have demonstrated that the efficiency of plasma-based laser-pumped soft x-ray lasers can be significantly increased by detailed pulse shaping of the pump laser using a new pulse synthesizer. Results include the demonstration of 18.9 nm wavelength laser operation at a record 400 Hz repetition rate, and the extension of repetitive gain-saturated plasma-based table-top x-ray lasers to the shortest wavelength to date, 6.85 nm. Laser amplification was also observed at wavelengths as short at 5.8 nm by isolectronic scaling in Ni-like lanthanide ions. We have also conducted simulations to explore the possibility of demonstrating gain saturated atomic x-ray lasers near the carbon K-edge, in the “carbon window” for the first time. The work conducted under this program also includes the use of compact soft x-ray lasers in applications to problems of chemical interest, such as isotopic composition mapping of micron-size uranium particles with nanoscale resolution, and nanoscale resolution depth profiling analysis of CoNCN-coated electrodes for water oxidation catalysis. We also demonstrated single-shot high resolution soft x-ray Fourier transform holography over a broad 7 µm diameter field of view with ~ 5 ps temporal resolution.
74 ATOMIC AND MOLECULAR PHYSICS↗
Very high cycle fatigue characteristics of laser beam powder bed fused AlSi10Mg: A systematic evaluation of part geometry
This study explores the influence of geometry and part size on defect distribution, melt pool size, and mechanical characteristics in laser beam powder bed fused (LB-PBF) AlSi10Mg. Five distinct geometries—hourglass, small rod, small block, large block, and large rod—were fabricated under identical process parameters. Fully reversed ultrasonic fatigue testing, operating at a frequency of 20 kHz, was conducted to assess the very high cycle fatigue properties. The findings indicated that part geometry had a major impact on the fatigue properties of the material in the very high cycle fatigue regime. Specimens machined from large rods and large blocks had the lowest porosity and highest fatigue resistance. Microstructural analysis indicated that hourglass, small rod, and small block specimens had shallower melt pools and overlap depths compared to other geometries. This observation suggests a higher cooling rate in specimens with smaller cross-sectional areas, leading to the increased presence of entrapped gas pores and a lack of fusion defects. Understanding the relationship between part geometry and fatigue properties in LB-PBF components offers insights for optimizing design and manufacturing processes in additive manufacturing applications.
AlSi10Mg↗
Laser beam directed at the lunar retro- reflector array - Observations of the first returns.
Lunar laser beam retroreflection observations, showing agreement with predicted ephemeris and signal strength
Carrion, W.↗
Small-angle approximation to the transfer of narrow laser beams in anisotropic scattering media
The broadening and the signal power detected of a laser beam traversing an anisotropic scattering medium were examined using the small-angle approximation to the radiative transfer equation in which photons suffering large-angle deflections are neglected. To obtain tractable answers, simple Gaussian and non-Gaussian functions for the scattering phase functions are assumed. Two other approximate approaches employed in the field to further simplify the small-angle approximation solutions are described, and the results obtained by one of them are compared with those obtained using small-angle approximation. An exact method for obtaining the contribution of each higher order scattering to the radiance field is examined but no results are presented.
Box, M. A.↗
Shielding Against Intense Laser Beams
Multiple-layer shielding proposed to protect equipment against damage by intense infrared laser beams. New shielding concept reduces effect of destructive phase changes upon reflectance by allowing exposure of additional reflecting layers after overlaying layers vaporized.
Schroeder, J. E.↗
Vertical laser beam propagation through the troposphere
The characteristics of the earth's atmosphere and its effects upon laser beams was investigated in a series of balloon borne, optical propagation experiments. These experiments were designed to simulate the space to ground laser link. An experiment to determine the amplitude fluctuation, commonly called scintillation, caused by the atmosphere was described.
Minott, P. O.↗
Measurement of light scattered from a laser beam by the atmosphere semiannual status report no. 2, 1 dec. 1964 - 31 may 1965
Measurement of laser beam light scattered by atmosphere
LIGHT SCATTERING↗
Program Models A Laser Beam Focused In An Aerosol Spray
Monte Carlo analysis performed on packets of light. Program for Analysis of Laser Beam Focused Within Aerosol Spray (FLSPRY) developed for theoretical analysis of propagation of laser pulse optically focused within aerosol spray. Applied for example, to analyze laser ignition arrangement in which focused laser pulse used to ignite liquid aerosol fuel spray. Scattering and absorption of laser light by individual aerosol droplets evaluated by use of electromagnetic Lorenz-Mie theory. Written in FORTRAN 77 for both UNIX-based computers and DEC VAX-series computers. VAX version of program (LEW-16051). UNIX version (LEW-16065).
Barton, J. P.↗
Exact wave solver for nonparaxial laser beam propagation
Simulations of inertial confinement fusion (ICF) experiments require high-fidelity models for laser beam propagation in a nonuniform plasma with varying index of refraction. We describe a new numerical wave solver that is applicable to centimeter-scale length plasmas encountered in indirect drive ICF applications. The one-way Helmholtz equation (OHE) generalizes the time-harmonic paraxial wave equation to large angles. Here, we present a methodology to numerically evaluate the exact solution to the OHE. This solution is computed by analytically advancing eigenfunctions of the one-way Helmholtz operator along a propagation direction and is applicable to any given index of a refraction profile. We compare our exact method with a commonly used approximate split-step technique for solving the OHE. As a test problem, we consider nonparaxial propagation of Gaussian and speckled beams in a plasma density channel with internal reflection. We find that the split-step approach incurs significant errors compared to the exact solution computed using the novel algorithm.
Belyaev, Mikhail A. (ORCID:0000000224908887)↗