Frequency doubling and tripling for future fusion drivers

Very-high average power frequency conversion is a key issue regarding laser driven inertial confinement fusion reactors. The merits of common non-linear crystals are discussed. The potential of lithium triborate is demonstrated by frequency doubling 235 J of infrared radiation at 1053 nm with 92% conversion efficiency. We also report on third harmonic generation of 360 J of ultraviolet at 351 nm with 80% efficiency.