z-dependent absorption and stimulated backscatter processes in laser produced plasmas

Abstract
Low‐ and high‐atomic‐number targets were irradiated at normal and oblique incidences with high focused intensity, 2.5‐nsec duration of 1.06‐μm laser pulses. Calorimetry and spectroscopy of ω and 2ω light reflected back into the focusing lens was performed. Results show a dramatic reduction in the specularly reflected light from high‐atomic‐number targets. Brillouin backscatter was observed throughout the range 1014–1016 W/cm2. 2ω spectra indicated the presence of an electron‐ion decay instability with a threshold at 2×1015 W/cm2.