Holographic interferometry of the gasdynamic collapse of a CO2 laser plasma near a target

The method of double-exposure holographic interferometry was used to investigate the gasdynamic collapse of a laser plasma initiated by a gigawatt CO₂ laser pulse. The laser beam was tubular and it was focused onto a carbon target. The holographic method enabled the parameters of the laser plasma to be measured with a spatial resolution of better than 25 μ. The spatial distribution of the electron density during the laser pulse interaction was determined. Estimates were obtained of the axial and radial velocities of the erosion laser plasma and an analysis was made of the relationship of these parameters to the experimentally determined shock wave velocity in the residual gas. It is proposed to use the laser plasma formed during a gasdynamic collapse as the active medium of short-wavelength lasers.