Studies on high power second-harmonic deep-UV generation from a high repetition-rate Cu-HBr laser

Abstract

This paper presents, for the first time, comprehensive studies on high power second harmonic deep ultraviolet (UV: λ ≈ 255.3 nm) generation from a low temperature, high repetition rate (18 kHz) variant of copper laser (Cu-HBr laser) with different optical resonators (plane–plane resonator and unstable resonators of magnifications 12.5, 50 & 100), pump-beam focussing condition and pump powers. With a type-I, critically phase matched β-barium borate (BBO) crystal as the harmonic generator and different pump average powers (⩽10 W) of the laser, the variation in UV average output powers and its conversion efficiencies were studied. The average UV power and conversion efficiency as high as about 2 W and 26% respectively were achieved. The experimental results were analysed in light of the beam quality attributes of the pump beams vis-à-vis limiting thermal and walk-off effects associated.