Widely tunable and high-average-power fourth-harmonic generation of a Ti:sapphire laser with a KBe2BO3F2 prism-coupled device.

Using a KBe(2)BO(3)F(2) prism-coupled device, we have realized the high-average-power output in the wide range from 170 to 232.5 nm by second-harmonic generation of a frequency-doubled Ti:sapphire laser. The output power in the UV from 175 to 232.5 nm exceeds 2 mW, the highest power being 119.8 mW at 202.5 nm. Moreover, tunable output powers above 100 mW have also been obtained for deep-UV light from 193.5 to 200 nm.