Scheme design of pulse duration compression in amplification of untraviolet ultrashort pulse laser

The discharge-pumped KrF excimer was used to amplify ultraviolet ultrashort pulse laser with wavelength of 248.4 nm.The laser energy was amplified from 0.7 mJ to 15 mJ,and the pulse duration was broadened from 550 fs to 1 200 fs, with the beam diameter of 10 mm unchanged. To compress the output pulse duration, the effects of group velocity dispersion and self phase modulation were analyzed,and experimental schemes with four different prism pair were used to introduce negative frequency chirp into the pulse laser in order to compensate the positive frequency chirp introduced by group velocity dispersion and self phase modulation in the CaF2 windows of the amplifer.The results show that if the prism pair is put before the amplifier, the pulse duration can be compressed to 370 fs when the le