High-power picosecond UV and deep-UV laser sources delivering powers of 30 W at 355 nm, 10 W at 266 nm, and 5 W at 213 nm.

Abstract

Utilizing LiB₃O₅, β-BaB₂O₄ crystals, and an Nd:YVO₄ laser with an average power of 70 W and a repetition rate of 100 kHz, we systematically demonstrated and operated high-repetition-rate, high-power, all-solid-state, UV, and deep-UV picosecond laser sources via high-efficiency third-, fourth-, and fifth-harmonic generation (THG, FHG, and FiHG). The maximum output powers of the radiation at 355, 266, and 213 nm reached 31.2, 10.6, and 4.86 W, respectively, and the highest conversion efficiencies from the 1064 nm infrared laser beam to its third, fourth, and fifth harmonics were up to 44.6, 15.3, and 7.16%, respectively. The intensity autocorrelation traces of the generated 355, 266, and 213 nm radiation were measured based on a two-photon absorption (TPA), and the extracted pulse durations were 7.7, 6.1, and 5.9 ps, respectively. This work validates the performance of the β-BaB₂O₄ crystal in obtaining deep-UV radiation, laying the foundation for compact high-power deep-UV devices. Especially the power of 213 nm radiation may be the highest power, to our knowledge, for the picosecond deep-UV radiation near the wave band of ∼200 nm.