Optical properties of a laser plasma near a solid surface in a dense gas

Experimental data are reported on the optical properties of a laser plasma produced by a pulse from a neodymium laser with q = 106--107 W/cm2 near a solid surface in nitrogen and carbon dioxide at pressures in the range 10--100 atm. A periodic change in the luminous emittance is observed at laser power density q = 3x106 W/cm2. This periodic change results from an oscillation which arises spontaneously in the system consisting of the laser beam, the ejection products, and the condensed medium. The events which occur are discussed qualitatively