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Results for “RUBY LASER”

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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Experimental study of the dynamics of a ruby laser pumped by a CW argon-ion laser

A study of the dynamics of a ruby laser pumped by a CW argon-ion laser is presented. The ruby laser is predominantly stable but has two accessible unstable states. One state exhibits chaotic output, while the other results in regular self-pulsing. The conditions needed for instability are discussed and homodyne spectra and temporal maps of the phase-space attractors are obtained. In addition, a numerical simulation of nonlinear beam propagation in ruby is presented that shows that strong deviations from plane-wave behavior exist, and that transverse effects must be incorporated into theoretical models of the instability.

Afzal, R. S.↗
NASA NTRS1988

Bistable polarization switching in a continuous wave ruby laser

Bistability in the output power, polarization state, and mode volume of an argon-ion laser pumped single mode ruby laser at 6943 A has been observed. The laser operates in a radially confined mode which exhibits hysteresis and bistability only when the pump polarization is parallel to the c-axis.

Lawandy, N. M.↗
NASA NTRS1975

Ionizing mechanisms in a cesium plasma irradiated with a ruby laser

A cesium filled diode--laser plasmadynamic converter was built to investigate the feasibility of converting laser energy to electrical energy at large power levels. Experiments were performed with a pulsed ruby laser to determine the quantity of electrons and cesium ions generated per pulse of laser beam and to determine the output voltage. A current density as high as 200 amp/sq cm from a spot of approximately 1 sq mm area and an open circuit voltage as high as 1.5 volts were recorded. A qualitative theory was developed to explain these results. In the operation of the device, the laser beam evaporates some of the cesium and ionizes the cesium gas. A dense cesium plasma is formed to absorb further the laser energy. Results suggest that the simultaneous absorption of two ruby laser photons by the cesium atoms plays an important role in the initial ionization of cesium. Inverse bremsstrahlung absorption appears to be the dominant mechanism in subsequent processes. Recombinations of electrons and cesium ions appear to compete favorably with the simultaneous absorption of two photons.

Shimada, K.↗
NASA NTRS1988

Bistable direction switching in an off-axis pumped continuous wave ruby laser

A report is presented of the observation of hysteretic bistable direction switching in a single-mode CW ruby laser system. This effect is only observed when the pump beam which is focused into the ruby rod is misaligned with respect to the rod end faces. At low pump powers, the ruby lases in a mode nearly collinear with the pump axis. At a higher pump power the ruby switches to a mode that is collinear with the rod end faces and preserves the original polarization. The effect is large enough to switch the beam by an angle equal to twice the diffraction angle. The observations show that under steady-state pumping, a CW ruby laser can exhibit bistable operation in its output direction and power. A calculation using the heat equation with two concentric cylinders with one as a heat source (pump laser) and the outer wall of the other held at 77 K, gives an increase in core temperature of about 0.01 K. Therefore, the increase in temperature is not large enough to change the index of refraction to account for such large macroscopic effects.

Afzal, R. Sohrab↗
NASA NTRS1974

Stress waves generated in thin metallic films by a Q-switched ruby laser

Investigation results on stress waves generated by Q-switched ruby laser irradiated thin metal films under confinement, studied over a wide range of film materials and film thicknesses, are reviewed. The results indicate that the dependence on these parameters is much weaker than is predicted by heat transfer estimations commonly used to describe the interaction of laser irradiation with unconfined bulk-solid surfaces.

Yang, L. C.↗
NASA NTRS1976

Ruby laser induced emission from NO2

Two different types of emission from excited NO2 were observed using pulsed ruby laser light at 6943 A. The first type of fluorescence was seen in the near IR and results from the single photon excitation of NO2 from the ground 2-A1 state. By observing the emission as a function of time an unexpected behavior was observed in the near IR and could be explained by a consecutive deactivation mechanism, wherein a secondary species is preferentially detected. A second type of emission recently observed in the blue spectral region is weaker and is due to a multiphoton process. The intensity of the blue emission is a function of the cube of the laser intensity at low pressures and approaches the square at high pressures. This variation is attributed to simultaneous deactivation of the excited NO2 intermediate by collision (square) and by anti-Stokes Raman scattering off of the excited NO2 (cube).

Hakala, D. F.↗
NASA NTRS1971

Detonation of insensitive high explosives by a Q-switched ruby laser.

Immediate longitudinal detonations have been observed in confined small-diameter columns of PETN, RDX, and tetryl by using a focused Q-switched ruby laser. The energy ranged from 0.8 to 4.0 J in a pulse width of 25 nsec. A 1000-A-thick aluminum film deposited on a glass window was used to generate a shock wave at the window-explosive interface when irradiated by the laser. In some cases, steady-state detonations were reached in less than .5 microsec with less than 10% variation in the detonation velocity.

Yang, L. C.↗