Design of a multi-petawatt optical parametric chirped pulse amplifier for the iodine laser ASTERIX IV

A theoretical design is presented for the generation of peak powers up to /spl sim/5 PW and focused intensities higher than 10/sup 23/ Wcm/sup -2/ with pulse duration /spl sim/20 fs using an optical parametric chirped pulse amplifier (OPCPA) pumped by the high-power iodine laser Asterix IV. These values represent an improvement to the existing Asterix laser by a factor of /spl sim/1000 and at least LOO 000 for the output peak power and focused intensity, respectively. The OPCPA system consists of two LBO preamplifiers and a KDP power amplifier and is pumped by the laser third-harmonic output (438 nm, 500 ps, 500 J). Numerical simulations show that saturation within the OPCPA can be effectively used to counteract the bandwidth narrowing effects brought about by the temporal variation of the pump pulse intensity. The results demonstrate that the OPCPA represents a powerful technique for the generation of ultrahigh powers with iodine lasers at a level currently not achievable with any other approach, and proves that the iodine system is particularly suitable as an OPCPA pump source.