High-power sixth-harmonic generation of an Nd:YAG laser with KBe2BO3F2 prism-coupled devices

High-power sixth harmonic generation from an Nd:YAG laser (10 ns, 10 kHz) has been achieved with a KBe2BO3F2 (KBBF) prism-coupled device (PCD) containing a 1.95 mm thick KBBF crystal. The highest output power reached 120.5 mW at 177.3 nm, and the highest conversion efficiency from 354.7 to 177.3 nm was 1.82%. Moreover, stable sixth harmonic output with an average power of 22.2 mW was produced by another KBBF-PCD, in which the thickness of the KBBF crystal was 1.51 mm. The highest and stable sixth harmonic output powers are improved by about three and six times compared with the previously published results, respectively.