Generation of 1.5 W average power, 18 kHz repetition rate coherent mid-ultraviolet radiation at 271.2 nm

This paper presents to our knowledge a first time study on the generation of 1.5 W average power, 18 kHz repetition rate coherent mid-ultraviolet (UV) radiation at 271.2 nm. The work is based on frequency summing of coherent green (G: 510.6 nm) and yellow (Y: 578.2 nm) radiations of a copper-HBr laser in a β-barium borate crystal. Average and peak sum frequency conversion efficiencies of about 13% and 16%, respectively, are obtained. The sum frequency results are experimentally analyzed in terms of the extent of matching of green and yellow pump radiations in space, time, and frequency domains. The result is of high significance for many applications in photonics components fabrication, semiconductor technology, and spectroscopy.