The transparency range of β-BaB<sub>2</sub>O<sub>4</sub> (BBO) was expanded by means of cooling, and the resulting absorption coefficient at 193.4 nm was reduced to 0.29cm<sup>-1</sup> at 91 K from 1.39cm<sup>-1</sup> at 295 K. Further, generation of light at 186.0 nm (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.
© 1999 Optical Society of America
(140.3610) Lasers and laser optics : Lasers, ultraviolet
(160.4330) Materials : Nonlinear optical materials
(190.2620) Nonlinear optics : Harmonic generation and mixing
(230.4320) Optical devices : Nonlinear optical devices
(300.1030) Spectroscopy : Absorption
Hikaru Kouta and Yasuhiko Kuwano, "Attaining 186-nm light generation in cooled β-BaB2O4 crystal," Opt. Lett. 24, 1230-1232 (1999)