PHASE-MATCHED HARMONIC-GENERATION IN LITHIUM TRIBORATE (LBO)

We present refractive index, thermo-optic, phase-matching angle, nonlinear coefficient, absorption, and scattering data on lithium triborate (LBO) crystals. The calculated angles for phase matching in the low birefringence y-z plane are in better agreement with direct measurements than previous reported values. The nonlinear coefficient measurements imply that d32 = 0.84 +/- 0.06 pm/V and d15 = 0.71 +/- 0.05 pm/V for frequency doubling of 1.064-mu-m. The calculated thermal sensitivity parameters for phase matching are in poor agreement with reported experimental values. It is shown that Type II doubling and third-harmonic generation of Nd:YAG harmonics can be significantly more efficient than Type I, but requires longer crystals or a more tightly focussed beam.