An enclosing "box" calorimeter has been used to measure the polarization and angular dependence of 1.06-μm laser-light absorption under experimental conditions approximating those assumed by Estabrook, Valeo, and Kruer in their simulations; i.e., ∼${10}^{16}$ W/${\mathrm{cm}}^2$ plane waves incident on a planar plasma. A clear resonance absorption maximum was observed for $p$-but not for $s$-polarized incident radiation as predicted.

• Received 13 May 1977

DOI:https://doi.org/10.1103/PhysRevLett.39.281