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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Large volume multiple path nuclear lasing of /He-3/-Ar

Output power of 550 W has been achieved from a nuclear-pumped multiple path laser system containing (He-3)-Ar by using the (He-3)(n, p)3(H) nuclear reaction for power deposition. Lasing was achieved in Ar at 1790 nm. The complex beam profile was resolved by an InAs array detector. Laser output was directly proportional to thermal neutron flux, and also increased proportionally with increasing (He-3) pressure up to 292.6 kPa. The variation of the laser output power with the number of passes through the excited medium was found to peak at 5-7 passes.

De Young, R. J.↗
NASA NTRS1981

Nuclear-pumped lasing of /He-3/-Xe at 2.63 microns

Direct nuclear pumping of an (He-3)-Xe laser, lasing at 2.63 microns, has been achieved. Scaling of the laser output with xenon concentration, total pressure, and thermal neutron flux has been investigated. A peak power in excess of 200 W was obtained at a total pressure of 3 atm, a gas mixture consisting of 5% xenon and 95% He-3, and a peak thermal flux of 6 x 10 to the 16th n/sq cm s.

Jalufka, N. W.↗
NASA NTRS1985

Lasing in N2O and CO2 isotope mixtures pumped by blackbody radiation

The use of N2O and CO2 isotopes as active species for a blackbody radiation pumped laser has been experimentally demonstrated and theoretically analyzed. The results obtained for mixtures containing N2O, (C-13) (O-16)2, and (C-12) (O-18)2 are presented. For the first time, continuous lasing action with blackbody radiation pumping has been obtained for this species. Two active species mixtures were tested, obtaining up to a 100 percent increase in output power due to v-v transfer. A simple model was developed and gain calculations are presented.

Sirota, J. M.↗
NASA NTRS1988

Studies of CW lasing action in CO2-CO, N2O-CO, CO2-H2O, and N2O-H2O mixtures pumped by blackbody radiation

A proof of principle experiment to evaluate the efficacy of CO and H2O in increasing the power output for N2O and CO2 lasing mixtures has been conducted and theoretically analyzed for a blackbody radiation-pumped laser. The results for N2O-CO, CO2-CO, N2O-H2O and CO2-H2O mixtures are presented. Additions of CO to the N2O lasant increased power up to 28 percent for N2O laser mixtures, whereas additions of CO to the CO2 lasant, and the addition of H2O to both the CO2 and N2O lasants, resulted in decreased output power.

Abel, Robert W.↗
NASA NTRS1991

Single-mode lasing of Ho:Tm:YAG at 2.091 microns in a monolithic crystal

This paper demonstrates single-longitudinal-mode lasing of Ho:Tm:YAG at 2.091 microns in a diode-laser-pumped monolithic crystal. Heterodyne detection at 2.1 microns is demonstrated, and energy diffusion effects on spatial hole burning are discussed. Temperature tuning over 4.5 A is demonstrated.

Storm, Mark E.↗
NASA NTRS1993

Investigation of 2.1-micron lasing properties of Ho:Tm:Cr:YAG crystals under flash-lamp pumping at various operating conditions

Flash-lamp-pumped normal-mode and Q-switched 2.1-micron laser operations of Ho:Tm:Cr:YAG crystals have been evaluated under a wide variety of experimental conditions in order to determine an optimum lasing condition and to characterize the laser outputs. Q-switched laser-output energies equal to, or in some cases exceeding the normal-mode laser energies, were obtained in the form of a strong single spike through an optimization of the opening time of a lithium niobate Q switch. The increase of the normal-mode laser slope efficiency was observed with the increase of the Tm concentration from 2.5 to 4.5 at. pct at operating temperatures from 120 K to near room temperature. Laser transitions were observed only at 2.098 and 2.091 microns under various conditions. The 2.091-micron laser transition appeared to be dominant at high-temperature operations with low-reflective-output couplers.

Kim, Kyong H.↗
NASA NTRS1993

Single-frequency lasing of monolithic Ho,Tm:YLF

Single-frequency lasing in monolithic crystals of holmium-thulium-doped YLF (Ho,Tm:YLF) is reported. A maximum single-frequency output power of 6 mW at a wavelength of 2.05 microns is demonstrated. Frequency tuning is also described.

Koch, Grady J.↗
NASA NTRS2000

Investigation of Mesoscale Variability in Convective Boundary Layer Development Using LASE

Throughout this research effort we have analyzed data collected from the Southern Great Plains 1997 (SGP) experiment to evaluate terms in the budget of water vapor in the atmospheric boundary layer (ABL). The analysis is centered on using data obtained from the Lidar Atmospheric Sensing Experiment (LASE) downward-looking differential absorption lidar (DIAL) that was flown on the NASA-P3 aircraft. The DIAL is able to measure vertical profiles of water vapor, as well as aerosol backscatter, throughout the ABL. Initial work on using the DIAL is summarized in the attached meeting preprint, which discusses results from a segment of the 12 July 1997 flight. Additional analysis has been carried out using both the DIAL data and in situ measurements to obtain more complete and detailed estimates of terms in the ABL water vapor budget. This includes data from the Canadian National Research Council Twin Otter aircraft, as well as from a spectrum of surface-based instruments. This work is expected to lead to a refereed article planned for submission to the Journal.

Lenschow, Donald H.↗
NASA NTRS2003

Lasing characteristics of InAs quantum dot laers on InP substrate

Single-stack InAs self-assembled quantum dots (QD) lasers based on InP substrate have been grown by metalorganic vapor phase epitaxy. The narrow ridge waveguide lasers lased up to 260 K in continuous wave operation, and near room temperature in pulsed mode, with wavelengths between 1.59 to 1.74 mu m.

quantum dot semiconductor laser↗
NASA NTRS1980

Lasing characteristics of gas mixtures involving UFG: Application to nuclear pumping of lasers

Intense blue-green fluorescence from a structured band centered at lambda approximately 484 nm was observed from Ar, CF3I and NF3 gas mixtures excited by an electron beam. This emission was tentatively assigned to the E yields A transition of the iodine monofluoride (IF) molecule. The fluorescence efficiency of the IF(E yields A) band and the IF (E) state radiative lifetime were estimated to be approximately 6% and 15 ns, respectively. The emission band structure, the short IF(E) radiative lifetime and the Franck-Condon shift between the E and A states suggest that IF is an attractive candidate for a blue-green laser.

Verdeyen, J. T.↗
NASA NTRS1988

Natural radio lasing at Jupiter

Like the comparable AKR radio emissions from earth's magnetosphere, the well-known decametric radio S-bursts from Jupiter, observed in France and Australia at frequencies from 10 to 26 MHz, have been found to exhibit equally spaced discrete spectral components which can be attributed to the adjacent longitudinal oscillation modes of natural radio lasers. Implying sizes of only a few kilometers for the individual radio lasers producing the S-bursts, the frequency spacing of these modes was roughly constant with frequency and about 30 to 50 kHz. Their corresponding temporal spacings, however, varied inversely proportional to the observing frequency, suggesting that the radio lasers producing the S-bursts were expanding uniformly at a rate of about 4 km/s. Presumably caused by the projected motion of Io with respect to the planet, this expansion of the S-burst radio lasers would account for the downward frequency drifts of the S-bursts without the energetic electron bunches which have heretofore always been assumed necessary to account for such behavior.

Calvert, W.↗
NASA NTRS1993

Testing For Parasitic Lasing With Controlled Retroreflection

Controlled-retroreflection technique provides new capability to test safely for parasitic oscillations in laser. Continuously variable reflector adjusted continuously over dynamic range of about 3 decades by rotation of quarter-wave plate about optical axis. Neutral-density filter establishes maximum reflectivity. By selection of neutral-density filters and continuous adjustment, reflector made to have any reflectivity from about 1 down to 10 to the negative 8th power.

Storm, Mark E.↗