Search NASA⌕ Search

SEARCH · Search NASA

Results for “NEODYMIUM LASERS”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Analysis of a 10 megawatt space-based solar-pumped neodymium laser system

A ten megawatt solar-pumped continuous liquid laser system for space applications is examined. It is found that a single inflatable mirror of 434 m diameter used in conjunction with a conical secondary concentrator is sufficient to side pump a liquid neodymium lasant in an annular tube of 6 m length and 1 m outer and 0.8 m inner diameter. About one fourth of intercepted radiation converging on the laser tube is absorbed and one fifth of this radiation is effective in populating the upper levels. The liquid lasant is flowed through the annular laser cavity at 1.9 m/s and is cooled via a heat exchanger and a large radiator surface comparable in size to the concentrating mirror. The power density of incident light within the lasant of approximately 68 watt/cu cm required for cw operation is exceeded in the present annular configuration. Total system weight corresponds to 20,500 kg and is thus capable of being transported to near Earth orbit by a single shuttle flight.

Kurweg, U. H.↗
NASA NTRS1984

Potential for coherent Doppler wind velocity lidar using neodymium lasers

Existing techniques for the frequency stabilization of Nd:YAG lasers operating at 1.06 micron, and the high-gain amplification of radiation at that wavelength, make possible the construction of a coherent Doppler wind velocity lidar using Nd:YAG. Velocity accuracy and range resolution are better at 1.06 micron than at 10.6 microns at the same level of the SNR. Backscatter from the atmosphere at 1.06 micron is greater than that at 10.6 microns by about 2 orders of magnitude, but the quantum-limited noise is higher by 100 also. Near-field attenuation and turbulent effects are more severe at 1.06 micron. In some configurations and environments, the 1.06-micron wavelength may be the better choice, and there may be technological advantages favoring the use of solid-state lasers in satellite systems.

Kane, T. J.↗
NASA NTRS1988

Diode laser-pumped solid-state lasers

An evaluation is made of the consequences for solid-state lasers of novel diode laser-pumping technology. Diode laser-pumped neodymium lasers have operated at an electrical-to-optical efficiency of 10 percent in a single spatial mode, with linewidths of less than 10 kHz, and with a spectral power brightness sufficiently great to allow frequency extension by harmonic generation in nonlinear crystals; this has yielded green and blue sources of coherent radiation. Q-switched operation with kW peak powers and mode-locked operation with 10-picosec pulse widths have also been demonstrated. All-solid-state lasers at prices comparable to those of current flash-lamp-pumped laser systems are foreseen, as are power levels exceeding 1 kW, for coherent radar, global satellite sensing, and micromachining.

Byer, Robert L.↗
NASA NTRS1980

Neodymium YAG lasers. Citations from the International Aerospace Abstracts data base

Various aspects of neodymium yag lasers are discussed in approximately 267 citations. Laser materials and outputs, laser mode locking; crystal, fiber, and nonlinear optics, optical pumping communications, energy conversion efficiency, and laser applications are covered. Pulsed, continuous wave, solid state, Q switched, infrared, and dye lasers are included.

Mauk, S. C.↗
NASA NTRS1985

Solar-pumped solid state Nd lasers

Solid state neodymium lasers are considered candidates for space-based polar-pumped laser for continuous power transmission. Laser performance for three different slab laser configurations has been computed to show the excellent power capability of such systems if heat problems can be solved. Ideas involving geometries and materials are offered as potential solutions to the heat problem.

Williams, M. D.↗
NASA NTRS1987

Parametric study of laser photovoltaic energy converters

Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

Walker, G. H.↗
NASA NTRS2014

DBR and DFB Lasers in Neodymium- and Ytterbium-Doped Photothermorefractive Glasses

The first demonstration, to the best of our knowledge, of distributed Bragg reflector (DBR) and monolithic distributed feedback (DFB) lasers in photothermorefractive glass doped with rare-earth ions is reported. The lasers were produced by incorporation of the volume Bragg gratings into the laser gain elements. A monolithic single-frequency solid-state laser with a line width of 250 kHz and output power of 150 mW at 1066 nm is demonstrated.

Photo-Thermal Refractive Glasses↗
DOE OSTI2020

Soft X-ray and EUV emission spectra of beryllium plasma produced by neodymium-glass laser radiation with broad frequency and angular spectra

We present the results of an experimental study of soft X-ray (SXR) and extreme ultraviolet emission spectra of the plasma produced by exposing a plane solid beryllium target to laser radiation with broad frequency and angular spectra. SXR lines up to 1s – 9p of Be IV as well as the plasma continuum are recorded for a laser focal-spot intensity of 5.3 × 10{sup 13} W cm{sup −2}. To model the SXR beryllium plasma spectra, simulations are carried out using the INDHAUS programme and the FLYCHK code in the framework of local thermodynamic equilibrium model, which agree nicely with experimentally obtained results. (laser plasma)

36 MATERIALS SCIENCE↗
NASA NTRS1992

Post flight operation of a high peak power neodymium YAG laser aboard the G-449 payload flown on Space Shuttle Columbia mission 61-C

The Nd Yag laser flown on board the G-449 payload completed its postflight testing successfully. There was no indication that the laser had undergone any electronic or optical component failure. A postflight video was taken immediately following the return of the payload to the laboratory. Early anticipation of vibration and temperature changes contributed to the successful operation of the laser. Photographic material resulting from post flight videotape are presented. NASA safety reviews and recommendations supplied the insights which helped contribute to the successful operation of the Nd Yag laser. The safety review data is part of the technical presentation and gives some insight into why the system survived the severe environment of temperature and vibration during the flight of Space Shuttle 61-C.

Muckerheide, M. C.↗
DOE OSTI2020

Experimental investigation of laser ablation of stone polycrystalline targets

We report the results of an experimental investigation of ablation of stone polycrystalline targets of complex multicomponent composition, which imitate the substance of asteroids. The targets were irradiated by nanosecond pulses of a neodymium laser at an energy density Φ{sub L} of up to 5 × 10{sup 4} J cm{sup −2}. The experiments demonstrated the existence of two ablation regimes, with the boundary between them lying at Φ{sub L} ≈ 4000 J cm{sup −2}. The regime change is characterised by a change in the form of the dependence of the surface mass density of removed target material on the laser energy density and by the appearance of a minimum in the dependence of specific energy of destruction on Φ{sub L}. This is supposedly related to the passage from a one-dimensional plasma plume expansion to the three-dimensional one and the corresponding decrease in the efficiency of energy transfer from the laser beam to the target due to a lowering of laser-produced plasma density. Our experiments also showed the existence of a maximum in impulse coupling coefficient C{sub m} as a function of laser energy density (C{sub m} ≈ 6.3 × 10{sup −5} N W{sup −1} for Φ{sub L} = Φ{sub opt} ≈ 25 J cm{sup −2}). Maxima were also recorded in the dependences of the ablation efficiency and average ablation flow velocity on Φ{sub L}. For Φ{sub L} > Φ{sub opt}, the decrease in the function C{sub m}(Φ{sub L}) turns out to be much steeper than for metals and polymer materials. The difference is supposedly due to the lower strength and lower plasticity of the polycrystalline stone targets. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1973

Photographic laboratory studies of explosions.

Description of a series of cinematographic studies of explosions made with a high-speed rotating-mirror streak camera which uses a high-frequency stroboscopic ruby laser as the light source. The results obtained mainly concern explosions initiated by focused laser irradiation from a pulsed neodymium laser in a detonating gas consisting essentially of an equimolar mixture of acetylene and oxygen at an initial pressure of 100 torr at room temperature. Among the most significant observations were observations of a spherical blast wave preceded by a Chapman-Jouguet detonation which is stabilized immediately after initiation, the merging of a spherical flame with a shock front of the blast wave in which the flame is propagating, the division of a spherical detonation front into a shock wave and flame, and the generation of shock waves by a network of spherical flames.

Kamel, M. M.↗
NASA NTRS1973

A High-efficiency, Small, Solid-state Laser for Pyrotechnic Ignition

A completely self-contained, small, neodymium laser has been designed and demonstrated for use in a pyrotechnic ignition system. A nominal 16 J of laser energy (1.06 micron wavelength, 1-ms duration) was achieved in a rectangular 10.5-X 15.1-X 25.4-cm package weighting 5.14 kg. This high energy-to-weight ratio is encouraging for laser applications in which specific energy efficiency (energy per unit weight or volume) is important. The laser design concepts are described, and some results on pyrotechnic ignition are given. Some details on a laser currently under construction, which will be 1/8 the size of the above laser, are included.

Yang, L. C.↗
NASA NTRS1992

Optimization of rod diameter in solid state lasers side pumped with multiple laser diode arrays

Results of a study to determine the optimum laser rod diameter for maximum output energy in a solid state neodymium laser transversely pumped with multiple laser diode arrays are reported here. Experiments were performed with 1.0 mm, 1.5 mm and 2.0 mm rod radii of both neodymium doped Y3Al5O12 (Nd:YAG) and La2Be2O5 (Nd:BeL) pumped with laser diode arrays having a maximum combined energy of 10.5 mJ. Equations were derived which predict the optimum rod radius and corresponding output mirror reflectivity for a given laser material and total pump energy. Predictions of the equations agreed well with the experiments for each of the laser materials which possessed significantly different laser properties from one another.

Sims, Newton, Jr.↗
NASA NTRS1979

The LASL program in nuclear pumped liquid lasers

The development of nuclear-pumped, liquid-based lanthanide ion lasers is discussed. Early investigations of lanthanide ion lasers have lead to solid-state and gaseous neodymium lasers, and a demonstration of lasing in the liquid state. Solvents containing organic chelating agents have been employed in liquid Eu(+3) and Tb(+3) lasers to extend fluorescence lifetimes, however aprotic solvents have been found to enable the development of large-scale liquid lasers. The advantages to be gained from high-power nuclear-pumped lasers based on lanthanide solutions include the high density of fissile materials possible, and a nuclear pumping cell which can operate in either a nuclear or optical pumping mode is being fabricated at the Los Alamos Scientific Laboratory to investigate the nuclear pumping of liquid lanthanide ion lasers. Areas that need exploration before specific laser design features can be considered include energy channeling within the liquid upon excitation, radiation damage due to solvent dissociation, and reactor technology for the development of a self-critical liquid reactor.

Mansfield, C. R.↗