Absorption of laser radiation by Al, Fe, and Au planar metallic targets

Experiments to determine the absorptance of an 8-nsec (FWHM) 1.064-μm laser pulse incident on metallic targets were performed using a well-characterized integrating sphere photometer. The absorptance was inferred by individually measuring the incident, back reflectd, and scattered laser radiation over the range ≃1013–1014 W/cm2 for three different elemental planr targets (Al, Fe, and Au). The absorptance varied approximately linearly from 0.9 at 1013 W/cm2 at 1014 W/cm2 and was independent of target material. The experimental accuracy was ±4%.