Attaining 186-nm light generation in cooled β-BaB2O4 crystal

The transparency range of P-BaB2O4 (BEO) was expanded by means of cooling, and the resulting absorption coefficient at 193.4 nm was reduced to 0.29 cm(-1) at 91 K from 1.39 cm(-1) at 295 K. Further, generation of light at 186.0 nn (the measurement limit in air) by type I sum-frequency generation (SFG) based on fundamental (744-nm) and third-harmonic (248-nm) light from a Ti:sapphire laser was confirmed for cooled BBO. Calculations based on observed data for SFG wavelengths and phase-matching angles indicate a potential for cooled BBO to generate wavelengths as low as 181.7 nm. (C) 1999 Optical Society of America.