Reflection Losses from Laser-Produced Plasmas

Abstract

Optical calorimetry of laser radiation reflected from plane targets irradiated by a 0.3 J/30 ps Nd-laser pulse (λ = 1.06 μm) has been performed. A 2π-ellipsoidal mirror was used for scattered light collection. We find that scattering outside the solid angle of the focusing lens is a major reflection loss from the target. A maximum fraction of 0.5 of the incident pulse energy was absorbed in the target with only a very weak dependence on pulse energy and target material. We emphasize that measurements made with sharp focusing on the target surface are difficult to compare with theoretical models in the plane wave/plane target approximation