Production of a plasma with a temperature of 1 keV by the action of a subpicosecond laser pulse with a 1012 contrast on a solid

A method for measuring the target potential was used to determine the peak electron temperature of a plasma produced by the action of a laser pulse (of 0.8 ps duration and of contrast in excess of 10¹²) on a metal target. The electron temperature increased linearly with the radiation intensity, reaching 1 keV at 2.3 × 10¹⁶ W cm^–2. This temperature was independent of the polarisation of the optical field incident obliquely on the target. The observed effect was interpreted by inverse-bremsstrahlung absorption in a plasma of density approaching that of a solid.