J. Phys. Colloques
Volume 41, Numéro C9, Novembre 1980Third International Symposium on Gas-Flow and Chemical Lasers
|Page(s)||C9-87 - C9-93|
J. Phys. Colloques 41 (1980) C9-87-C9-93
TRANSIENT OPTICAL PROPERTIES OF TARGET INDUCED LASER SUPPORTED ABSORPTION WAVESM. Hugenschmidt, W. Baca et J. Wey
German-French Research Institute Saint-Louis (ISL), 12, rue de l'Industrie, 68301 Saint-Louis, France.
Efficient energy transfer from short duration high-power laser pulses to metallic as well as dielectric targets causes serious problems as strongly absorbing plasmas are initiated when the power density applied exceeds a threshold of the order of 106 to 107 W/cm2. The purpose of our investigations was to determine temporal relaxation processes of the optic transparency of plasmas produced by powerful CO2 laser pulses. The laser system was capable of giving single or double pulses with energies (in both pulses) up to 150 J. The time delay could be varied arbitrarily. The formation and decay of the plasma absorption waves were investigated up to power densities of some 108 W/cm2 by means of a low power cw CO2 probe laser. The relaxation time the plasma needs for reattaining transparency which was thus determined, is a most important parameter which has to be considered if, for example, optical energy has to be transferred to a target by repetitively pulsed lasers.