Development of a hiigh‑powerhigh‑repetition rate diode‑phmped deep UV Iaser system

ウシオ電機株式会社 Copyright(C)USHIO INC. All Right Reserved Introduction There has been great interest in the development of UV and deep-UV Iaser systems fot industrial, scientific, and medical applications. The achievement of high-average power, deep-UV radiation via the fourth and fifth harmonic generation of diode-pumped 1-μm lasers is of particular importance for the semiconductor photolithography industry, since this provides part of the pathway to 193-nm generation. One of the difficulties in the development of high power UV or deep-UV is the availability of suitable nonlinear crystals and their thermal management due to linear and/or nonlinear absorption. Recently CLBO has proven to be a promising candidate in this area. Development work with this material has been reported by Yap et al.[l], Stamm et al.[2], and recently 192-nm generation using CLBO has been demonstrated by Deki et al.[3]. In many industrial applications, high repetition rate, as well as high average power, is an important issue in terms of throughput or total performance. The majority of the high power UV generation has been confined to 100-Hz repetition rates. UV generation. using diodepumped Ndbased systems, has been reported at higher repetition rates by Masuda et al.[4] but only with single Watt-level power generation in the UV. In this paper, we report on a high-power, high-repetition, all-solid-state, UV laser system generating 6.6W at 262nm and 2.0W at 209nm using CLBO. The system utilizes a diode-pumped Nd:YLF 1047-nm MOPA system which produces 37W CW and 29W Q-switched TEM00 output power at a 5-kHz repetition rate. Development of a hiigh-power,high-repetition rate, diode-phmped, deep UV Iaser system