Wang, Yong, authorWang, Shoujun, authorRockwood, Alex, authorLuther, Bradley M., authorHollinger, Reed, authorCurtis, Alden, authorCalvi, Chase, authorMenoni, Carmen S., authorRocca, Jorge J., authorOptical Society of America, publisher2020-04-282020-04-282017-09-22Yong Wang, Shoujun Wang, Alex Rockwood, Bradley M. Luther, Reed Hollinger, Alden Curtis, Chase Calvi, Carmen S. Menoni, and Jorge J. Rocca, "0.85  PW laser operation at 3.3  Hz and high-contrast ultrahigh-intensity λ = 400  nm second-harmonic beamline," Opt. Lett. 42, 3828-3831 (2017) https://doi.org/10.1364/OL.42.003828https://hdl.handle.net/10217/206006We demonstrate the generation of 0.85 PW, 30 fs laser pulses at a repetition rate of 3.3 Hz with a record average power of 85 W from a Ti:sapphire laser. The system is pumped by high-energy Nd:glass slab amplifiers frequency doubled in LiB3O5 (LBO). Ultrahigh-contrast λ = 400 nm femtosecond pulses were generated in KH2PO4 (KDP) with>40% efficiency. An intensity of 6.5 × 1021 W∕cm2 was obtained by frequency doubling 80% of the available Ti:sapphire energy and focusing the doubled light with an f∕2 parabola. This laser will enable highly relativistic plasma experiments to be conducted at high repetition rate.born digitalarticleseng©2017 Optical Society of America. Authors may also opt to make their articles freely available in our hybrid journals, Applied Optics, Journal of the Optical Society A, Journal of the Optical Society B, Optics Letters, and Journal of Optical Communications and Networking. https://www.osapublishing.org/submit/review/open-access-policy-statement.cfm.Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.diode pumped lasersfemtosecond lasersfemtosecond pulseslaser amplifierslaser operationti:sapphire lasersTexthttps://doi.org/10.1364/OL.42.003828