Abstract

Interaction of laser radiation with matter at relativistic intensity requires laser pulses with a very clean temporal shape. The temporal contrast of high intensity laser systems based on laser gain materials and optical parametric amplification is determined substantially by the level of amplified spontaneous emission (ASE) and parametric fluorescence, respectively, originating from the laser front end [1]. It is remarkable that the temporal contrast of amplified and recompressed pulses grows nearly linear with the energy injected in the laser power amplifiers. During the last few years considerable efforts have been devoted to increase the temporal ASE contrast of high intensity systems. These latters include the invention of the double chirped pulse amplification (DCPA) [2] architecture, that implements intermediate pulse recompression and nonlinear temporal filtering of the short pulse, investigation of nonlinear methods [3-6] required for the practical realization of a reliable DCPA, and also the development of plasma mirror technique [7], that supports substantial improvement of temporal contrast, but is currently applicable only to low repetition rate systems.

© 2013 IEEE