High-contrast front end based on cascaded XPWG and femtosecond OPA for 10-PW-level Ti:sapphire laser

By combining cross-polarized wave generation and femtosecond optical parametric amplification, a high-contrast front end featuring ultrahigh contrast, a broadband spectrum, an excellent beam profile, and good stability is built for a 10-PW-level Ti: sapphire laser in the Shanghai Superintense Ultrafast Laser Facility ( SULF-10PW laser). The front end can deliver a cleaned pulse with a 110 mu J energy at 1 kHz, and the bandwidth of the cleaned pulse exceeds 60 nm ( FWHM), which can support a 17 fs compressed pulse duration. The measured output energy fluctuation in one hour is <1.8% in rms value. The measurement-limited contrast is 10(-10) at 3 ps before the main pulse. Utilizing the high-contrast front end, single-shot contrast at 10(-10) level has been demonstrated in the SULF-10PW laser at a 24 fs pulse duration. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement