Recent development of the Orion Laser Facility and future perspectives

摘要

AWE’s Orion Laser Facility comprises ten 500J nanosecond (“long pulse”) beam lines (3ω) and two petawatt (“shortpulse”) beam lines, each delivering 500J, 500fs pulses at 1054nm. One short pulse beam can operate at 2ω (at reducedaperture), producing ultrahigh contrast pulses. This paper reports on recent developments and planned future work. Staticwavefront correctors have been implemented to mitigate prompt aberrations in the long pulse beams, which alter the onshotwavefront characteristics compared to the CW alignment beams. This mitigates aberration accumulation through theday, increasing the maximum number of shots in one shift. A TIM-mounted wavefront sensor/focal imager has been developed,which is better able to characterise the post-compression system aberrations, resulting in higher focal intensity.A diode-pumped, multi-joule rod amplifier has been prototyped. This is planned to replace the ageing, flashlamp-basedns-OPCPA pump laser, which constitutes a single point failure mode for our short pulse capability. Preliminary designwork has commenced for a facility life-extension project, planned for ~2023. The infrared performance will be enhancedto ~1kJ per beam in 300fs, the additional bandwidth being supported by greater use of silicate glass. The two-grating,single-pass compressor systems will be replaced by four-grating compressors, retaining the extant vacuum vessels. Thefrequency doubling option will be retained. Since the greater near-field intensity inevitably over-drives the doublers,compressor detuning is necessary. We assess a novel, small compressor at the second harmonic. Simulations suggest thatup to 500J in 150fs is possible in this configuration.