Comparative Reflectance Measurements on Laser-Produced Plasmas at 1.06 and 0.53 μm

The total and specular reflectances of 1.06- and 0.53-μm laser pulses were measured on planar copper targets. The measurements were made with 30-ps pulses and an intensity on target of ${10}^{14}$ W/${\mathrm{cm}}^2$. The direction of polarization and angle of incidence (0°-70°) were varied. Only a weak dependence of reflectance on wavelength is found; at both wavelengths reflectance is governed by the characteristic angle and polarization dependence of resonance absorption.