Widely tunable deep ultraviolet generation in CLBO

Abstract In a single cut cesium lithium borate (CsLiB 6 O 10 or CLBO) crystal we have generate deep UV radiation tunable from 195 to 265 nm (with a gap from 210 to 226 nm due to crystal cut limitation). Radiation in the 195–210 nm region is generated by noncollinear sum-frequency mixing of Nd:YAG laser radiation with the second harmonic (239–262 nm) of the dye laser radiation. However, radiation in the region of 210–237.5 nm and 236.8–265 nm is generated by third harmonic and second harmonic generation of the dye laser, respectively. All three interactions for coverage of the said range are made in the same cut CLBO crystal Type-I, θ =80° and ϕ =45°. The shorter wavelength tuning is phase-matching limited. A conversion efficiency of 14% is realised in our 5.5 mm long crystal for the generation of 241.7 nm radiation by Type-I second harmonic generation with a fundamental input beam intensity as low as 14.6 MW/cm 2 .