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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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Exploring mounting solutions for cryogenically cooled thin crystal optics in high power density x-ray free electron lasers

This study investigates three mounting methods—clamping, soldering, and a hybrid clamping–soldering approach—for cryogenically cooled thin diamond crystals crucial to stable operation of X-ray Free Electron Laser (XFEL) systems. While clamping methods exhibit temperature resilience and flexibility, meticulous design is required to prevent stress-induced warping and reduce thermal contact area. Soldering methods offer reliable mechanical and thermal bonding but encounter challenges due to the coefficient of thermal expansion mismatch at cryogenic temperatures. The hybrid method, integrating clamping and soldering with strain relief cuts, effectively mitigates overall distortion caused by mounting and XFEL thermal loads. These findings offer a novel mounting solution for high-performance x-ray optics in XFEL research and applications, ensuring stability and optimal functionality in cryogenic conditions.

Instruments & Instrumentation↗
NASA NTRS2000

Generation of a Cold Atom Beam from a Pyramidal Magneto-Optical Trap

We have built an atomic beam source utilizing a simple and robust design based on the pyramidal trap geometry of Kim et al. Our design allows use of a single large diameter (\le20 cm) laser beam to obtain large capture rates of atoms from a background vapor. A small (about 1mm diameter) hole in the retro-optic at the apex of the pyramid provides an extraction column for the atoms. We have operated the apparatus both as a magneto-optical trap (using an auxiliary plug laser beam), and as a cold atomic beam source. The characterization of this large pyramidal beam source will be reported, including an investigation of scaling to very large (10--20cm) high power (about 1W) laser beams which should allow significant improvements in atomic beam flux.

Bliss, J. L.↗
NASA NTRS2003

Laser Velocimeter for Studies of Microgravity Combustion Flowfields

A velocimeter was developed based on modulated filtered Rayleigh scattering (MFRS). The MFRS velocimeter was successfully demonstrated by making one-component velocity measurements in a supersonic expansion using molecular Rayleigh scattering in a jet of N2. These measurements were made in a sweep mode where the Rayleigh scattered profile is cross-correlated with absorption in a static cell to determine velocity. To improve temporal resolution the frequency-locked mode of operation was developed, with an in-situ referencing scheme to compensate for signal fluctuations arising from density variations in the probe volume. Spectroscopic grade (i.e. continuously tunable, single-mode) laser sources with high power (greater than 100 mW) are not commercially available at the wavelength of interest (780 nm). We developed an all-solid-state system with a low power (approximately 10 mW) spectroscopic grade laser source in a Littrow cavity is amplified by a broad-area diode laser. We have demonstrated that the slaved output tracks the injected input but have not yet demonstrated power gain by the end of the grant period.

Varghese, Philip L.↗
NASA NTRS1988

Overview and future direction for blackbody solar-pumped lasers

A review of solar-pumped blackbody lasers is given which addresses their present status and suggests future research directions. The blackbody laser concept is one system proposed to scale to multimegawatt power levels for space-to-space power transmissions for such applications as onboard spacecraft electrical or propulsion needs. Among the critical technical issues are the scalability to high powers and the laser wavelength which impacts the transmission optics size as well as the laser-to-electric converter at the receiver. Because present blackbody solar-pumped lasers will have laser wavelengths longer than 4 microns, simple photovoltaic converters cannot be used, and transmission optics will be large. Thus, future blackbody laser systems should emphasize near visible laser wavelengths.

Deyoung, R. J.↗
DOE OSTI2025

Harnessing Ultra-Intense Long-Wave Infrared Lasers: New Frontiers in Fundamental and Applied Research

This review explores two main topics: the state-of-the-art and emerging capabilities of high-peak-power, ultrafast (picosecond and femtosecond) long-wave infrared (LWIR) laser technology based on CO2 gas laser amplifiers, and the current and advanced scientific applications of this laser class. The discussion is grounded in expertise gained at the Accelerator Test Facility (ATF) of Brookhaven National Laboratory (BNL), a leading center for ultrafast, high-power CO2 laser development and a National User Facility with a strong track record in high-intensity physics experiments. We begin by reviewing the status of 9–10 μm CO2 laser technology and its applications, before exploring potential breakthroughs, including the realization of 100 terawatt femtosecond pulses. These advancements will drive ongoing research in electron and ion acceleration in plasma, along with applications in secondary radiation sources and atmospheric energy transport. Throughout the review, we highlight how wavelength scaling of physical effects enhances the capabilities of ultra-intense lasers in the LWIR spectrum, expanding the frontiers of both fundamental and applied science.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

1 GW peak power and 100 J pulsed operation of a diode-pumped Tm:YLF laser

We report on the generation of high energy, high power pulses in a tabletop diode-pumped Tm:YLF-based laser system, which delivers amplified pulse energies up to 108 J, as well as GW peak power performance when seeded with nanosecond duration pulses. Furthermore, the high power and efficiency capabilities of operating Tm:YLF in the multi-pulse extraction (MPE) regime were explored by seeding the experimental setup with a multi-kHz burst of pulses exhibiting a low individual pulse fluence, resulting in a 3.6 kW average power train of multi-joule-level pulses with an optical-to-optical efficiency of 19%.

47 OTHER INSTRUMENTATION↗
NASA NTRS1981

Coupled optical resonators for the enhancement of laser intracavity power

A double-cavity optical configuration designed to maximize the power available from CW lasers is reported. A passive supplementary cavity is strongly coupled to the main active laser cavity. It is shown theoretically that higher powers are available inside the passive cavity than those achievable by operating the same laser in a two-mirror configuration designed for optimum coupling. Furthermore, the power inside the passive cavity is equal to or greater than the useful circulating power in the two-mirror configuration. Key aspects of the theory are verified with a high power CW argon laser.

See, Y. C.↗
NASA NTRS2018

2.0 um Wavelength Injection Seed Semiconductor Laser for Lidar Transmitter for Global-Scale Measurements of CO2

Many of the high accuracy Earth science survey missions are planned to use laser-based remote sensing instruments. The 2-μm laser wavelength is of particular interest due to the presence of many CO2 and H20 absorption lines in its vicinity1. Transmitter architectures are typically composed of an optically pumped, frequency-stable, solid-state seed laser and a high-power optical amplifier.2, 3 Taking advantage of the reliability and relative simplicity of semiconductor lasers, this architecture can substantially improve by replacing the solid-state light source with semiconductor lasers of comparable performance. This approach will greatly improve the system reliability, and will simplify instrument integration and space qualification. There are currently very limited semiconductor lasers operating in the 2-m range with performance satisfactory enough for use as an injection seed in a laser absorption spectrometer. Optimally, seed lasers producing greater than 50 mW of continuous-wave (CW), with frequency jitter of less than 1 MHz are desired to reliably resolve the CO2 absorption lines near 2-µm. In this paper, we report the demonstration of high-power, single-longitudinal-mode laterally coupled distributed feedback (LC-DFB) lasers at 2.05 µm wavelength. We measured more than 80 mW of CW power at -10 ºC for devices with a 4-µm-wide ridge and 2-mm-long cavity.

Fradet, Mathieu↗
NASA NTRS1991

High-power diode-pumped solid-state lasers for optical space communications

The design and performance of a large diode-pumped multi-stage Nd:YAG laser system for space and airborne applications will be described. The laser operates at a repetition rate of 40 Hz and produces an output either at 1.064 micron or 532 nm with an average power in the Q-switched mode of 30 W at the fundamental and 20 W at the second harmonic wavelength. The output beam is diffraction limited (TEM 00 mode) and can optionally also be operated in a single longitudinal mode. The output energy ranges from 1.25 Joule/pulse in the free lasing mode, 0.75 Joule in a 17 nsec Q-switched pulse, to 0.5 Joules/pulse at 532 nm. The overall electrical efficiency for the Q-switched second harmonic output is 4.

Koechner, Walter↗
NASA NTRS1999

Lasers For Wireless Power Transmission

Currently used for communications, lasers are also highly promising for wireless power transmission and off-board space propulsion, but safety concerns must be dealt with first.

Laser power beam safety space solar power↗
NASA NTRS2012

Miniature Tunable Laser Spectrometers for Quantifying Atmospheric Trace Gases, Water Resources, Earth Back-Contamination, and In Situ Resource Utilization

The Tunable Laser Spectrometers (TLS) technique has seen wide applicability in gas measurement and analysis for atmospheric analysis, industrial, commercial and health monitoring and space applications. In Earth science using balloons and aircraft over 2 decades, several groups (JPL, NASA Langley & Ames, NOAA, Harvard U., etc) have demonstrated the technique for ozone hole studies, lab kinetics measurements, cloud physics and transport, climate change in the ice record. The recent availability of high-power (mW) room temperature lasers (TDL, IC, QC) has enabled miniaturized, high-sensitivity spectrometers for industry and space (1) Mars, Titan, Venus, Saturn, Moon (2) Commercial isotope ratio spectrometers are replacing bulkier, complex isotope ratio mass spectrometers.

Tunable laser spectrometers (TLS)↗
NASA NTRS2005

Holographic Flow Visualization at NASA Langley

Holographic flow visualization systems at two NASA Langley facilities, a hypersonic blow-down tunnel using CF4 gas and an expansion tube with very short test time, are described. A pulsed ruby laser is used at a CF4 tunnel for single pulse holography, double pulse with several minutes between exposures, and dual plate holographic interferometry. Shadow-graph, schlieren, and interferograms are reconstructed from the holograms in a separate reconstruction lab. At the expansion tube the short run time of 200 microseconds requires precise triggering of its double pulsed ruby laser. With pulse separation, one pulse can occur before and one after flow is established to obtain fringe free background interferograms (perfect infinite fringe) or both pulses can occur during flow in order to study flow instabilities. Holograms are reconstructed at the expansion tube with an in-place setup which makes use of a high power CW Argon laser and common optics for both recording and reconstructing the holograms. The holographic systems at the CF4 tunnel and expansion tube are operated routinely for flow visualization by tunnel technicians. Typical flow visualization photographs from both facilities are presented.

Burner, A. W.↗
NASA NTRS2003

Narrow linewidth single-mode semiconductor laser development for coherent detection lidar

High power, tunable, single mode, narrow linewidth semiconductor lasers in the 2.05-(micro)m wavelength region are needed to develop semiconductor laser reference oscillators for optical remote sensing from Earth orbit. 2.05-I1/4m narrow linewidth monolithic distributed feedback (DFB) and distributed Bragg reflector (DBR) with the external grating ridge waveguide lasers fabricated from epitaxially grown InGaAs/InGaAsP/InP and in InGaAsSb/AlGaAsSb/GaSb heterostructures are reported.

single mode↗
NASA NTRS1979

Holographic flow visualization at NASA Langley

Holographic flow visualization systems at two NASA Langley facilities, a hypersonic blow-down tunnel using CF4 gas and an expansion tube with very short test time, are described. A pulsed ruby laser is used at a CF4 tunnel for single pulse holography, double pulse with several minutes between exposures, and dual plate holographic interferometry. Shadowgraph, schlieren, and interferograms are reconstructed from the holograms in a separate reconstruction lab. At the expansion tube the short run time of 200 microseconds requires precise triggering of its double pulsed ruby laser. With double pulse capability of 20 to 1200 microseconds pulse separation, one pulse can occur before and one later after flow is established to obtain fringe free background interferograms (perfect infinite fringe) or both pulses can occur during flow in order to study flow instabilities. Holograms are reconstructed at the expansion tube with an in-place setup which makes use of a high power CW Argon laser and common optics for both recording and reconstructing the holograms. The holographic systems at the CF4 tunnel and expansion tube are operated routinely for flow visualization by tunnel technicians. Typical flow visualization photographs from both facilities are presented.

Burner, A. W.↗
DOE OSTI2022

U.S. advanced and novel accelerator beam test facilities

Demonstrating the viability of Advanced Accelerator Concepts (AAC) relies on experimental validation. Over the last three decades, the U.S. has maintained a portfolio of advanced and novel accelerator test facilities to support research critical to AAC. The facilities have enabled pioneering developments in a wide variety of beam and accelerator physics, including plasma-wakefield and structure-wakefield acceleration. This work provides an overview of the current portfolio of U.S. facilities possessing charged particle drive beams with high energies, on the order of tens of joules per pulse, or drive lasers with high peak powers, on the order of a petawatt, and are actively conducting AAC research.

43 PARTICLE ACCELERATORS↗