We have successfully resolved the degradation problem of CsLiB(6)O(10) (CLBO) by means of elevated crystal temperature. CLBO crystals were continuously operated at 160 degrees C in ordinary room humidity. No degradation of performance was observed after more than 1 month. We believe that heating CLBO crystal above 130 degrees C can relieve stresses introduced by crystal hydration, cutting, polishing, and thermal shock owing to laser power absorption. Thus long-term operation of CLBO crystal is achieved for effective application of laser frequency conversion. Output stability from CLBO is also further enhanced at elevated crystal temperature.

Large single crystals of CsB3Os (CBO), free of cracks and inclesions, were sncees~uily grown by the Kyropoulos technique from a slightly Cs20-enriched melt. The growth conditions were experimentally established. Maximum dimensions obtained were 45 × 41 x 44 nun for a x b x c-axes. Optical uniformity of these as-grown crystals was verified by means of striation observation, and the optical transparency characteristic was measured in the region from vacuum ultraviolet (VUV) to infrared (IR) wavelengths.

A study of the mechanisms of CsLiB6O10 (CLBO) crystal performance degradation during harmonic generation in the ultraviolet (UV) region was performed. The degradation rate of transmissivity during irradiation with the fourth harmonic light of an Nd3+ doped YLiF4 laser (4.7 eV) was linearly proportional to the concentration of hydroxyl (OH) groups in the CLBO crystal. In this study, the formation of OH groups was recognized by infrared absorption spectroscopy, and a method for determination of OH groups was proposed. The concentration of OH groups in the CLBO was linearly proportional to water vapor pressure and the CLBO containing OH groups absorbed UV light. We propose that one of the main mechanisms of surface degradation is the generation and growth of the mutants and that these mutants are generated by a UV photon-assisted reaction via OH group formation associated with absorbing water molecules into CLBO crystal.

The phenomenological basic equations to express ionic behavior in liquid crystals were derived and discussed. The basic equations are the conventional torque balance equation and equation of motion, and novel modified Poisson equation and diffusion equation. Surface anchoring and the orientational order parameter were also considered. Using these basic equations, the macroscopic director structure will become completely calculable.