New observations on DUV radiation at 257 nm and 206 nm produced by a picosecond diode pumped thin-disk laser

• Published in: Optics express 2019-08, Vol.27 (17), p.24286-24299
• Main Authors: Turcicova, Hana, Novak, Ondrej, Roskot, Lukas, Smrz, Martin, Muzik, Jiri, Chyla, Michal, Endo, Akira, Mocek, Tomas
• Format: Article
• Language: English
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.27.024286

We report new observations on picosecond deep ultraviolet coherent beams generated in a CLBO as the fourth and fifth harmonics of a diode pumped high average power Yb:YAG thin disk laser operating at 77 kHz repetition rate at 1030 nm. The effects of the two-photon absorption were observed, e.g. the modification of phase matching conditions, lowering of the conversion efficiency. The fifth harmonic generation (4ω+1ω) was studied for different time delays between both pump beams and for the case of excess input power of the fundamental. The latter effect suggests a possibility of increasing DUV output at short crystals. The highest output power obtained at 257 nm was 7.6 W and 1 W at 206 nm. To our knowledge these DUV output powers rank among the highest for picosecond pulses at the repetition rate of the order of magnitude of 100 kHz.