Saturable absorbers for multiband operation of a high-gain short-pulse CO_2-laser chain

Park

Journal of Applied Physics

1986

Transient frequency shift induced by the electron density in injection locking of transversely excited atmospheric CO2 lasers Appl. Phys. Lett. 45, 197 (1984); 10.1063/1.95208Extended gas lifetime operation of a miniature transversely excited atmosphere CO2 laser doped with tripropylamine Appl. Phys. Lett. 41, 601 (1982);The operating rotational-vibrational transition lines are observed in a pulsed transversely excited atmospheric pressure C0 2 1aser with a separated intracavity CO 2 gas absorber. The laser operates a dominant 1O.6-,um P-20 and P-18 line in a low pressure of CO 2 cell and a single-line operation of P-20 line at more high pressure. In a high pressure, the laser does not operate the 1O.6-,um P-20 and P-18, but it operates the single-line operation of 1O.6-,um R-14, R-18, P-22, and 9.4-,um R-12, and in multiline oscillation, of various combinations of these lines and 1O.6-,um R-16, according to the temperature of this gas absorber. The results are attributed to the absorbing mechanism of the CO 2 gas.2717

Tunable multiline and single-line operations on a pulsed transversely excited atmospheric pressure CO2 laser by means of an intracavity CO2 gas absorber

Park

Journal of Applied Physics

1986

Multiwavelength laser solid–target interaction at 10 microns

Lavigne

Johnston

Pascale

et al. 1985

The Physics of Fluids

Some aspects of multiple-wavelength interaction on solid targets have been experimentally studied at CO2-laser wavelengths with 1-nsec pulses. Contrary to predictions, the use of a two-line (10.6- and 9.6-μm) source does not reduce the back reflection. This result could be explained by a very short Brillouin interaction length or/and a very low saturation level. The hot-electron production is also not significantly modified by multiline illumination. A signal at the frequency sum indicates that, even at Iλ2 as low as 5×1013 W cm−2 μm2, the critical surface is not well defined and that both the 9.6- and 10.6-μm light interact in the same resonant zone. Finally, significant sidebands were measured at 8.7 and 12 μm. Some 1 (1)/(2) -dimensional simulations with mobile ions indicate that those sidebands probably originate from the beat frequency resonant density at 0.0123nc.

Reduction of the hot electron energies with increasing pulse rise time in CO2-laser–target interaction

Decoste

Côté

Lavigne

et al. 1987

The Physics of Fluids

The effect of increasing the laser pulse rise time on the hot electron energy distribution is studied using one or three prepulses near or on the rise of a main CO2-laser pulse. For some slower rising pulses, the pressure from a hot and long gradient plasma balances the ponderomotive laser force in such a way that the hot electron energies are significantly reduced while the overall resonance absorption fraction remains almost the same. The experimental results are modeled with a 1-D hydrocode using multigroup fast electrons and a dependence of the absorption and the hot electron temperature on the density gradient scale length at the critical density. Qualitative agreement is obtained over a wide range of laser pulse conditions and rise times.