Abstract

Recently, we demonstrated the recompression of chirped mJ-level pulses in air using a Treacy-type compressor containing a tiled grating pair. Pulses being stretched from 100 fs to a duration of 2.2 ns were recompressed after amplification to less than 150 fs. Here, we present new results obtained by installing this optical arrangement in a vacuum chamber to be able to handle Joule-level pulses of the diode-pumped POLARIS laser system [1]. In Figure 1(a), we show the vacuum chamber system with vibration-damped optical tables inside. Within the chambers we are able to reach a final pressure of 1^*10⁻⁷ mbar. The beam is directed into the compressor chamber after an evacuated focussing telescope with variable magnification containing a pinhole for spatial cleaning of the pulses. The compressor chamber is capable of compressing beams with a maximum diameter of 150 mm clear aperture. The present status allows us to compress laser pulses up to a peak power of 40 TW. This is limited by the sizes of the first and last grating, which is 140^*120 mm², respectively, corresponding to a maximum beam diameter of 60 mm. In the final stage of extension utilizing larger gratings of 350^* 190 mm², the compressor will be able to compress pulses to peak powers in excess of 250 TW.

© 2007 IEEE