PHASE MATCHING FOR 2ND HARMONIC-GENERATION IN KNBO3-TA CRYSTALS WITH ND-YAG-LASER AND GAAS-LASER WAVELENGTHS

Abstract

Noncritical phase-matched second harmonic generation was measured in optically biaxial KNb(1-x)Ta(x)O3 mixed crystals in the orthorhombic phase. For Nd:YAG-(1064 nm) the coefficient d31 of the tensor of the nonlinear susceptibility was applied, while for the GaAs-laser (905 nm) the coefficient d32 was used. For both laser wavelengths the phase-matching temperature decreases with increasing Ta concentration. Noncritical phase-matching at room temperature can be reached with the GaAs-laser for a Ta concentration of almost-equal-to 9%. The corresponding value for the Nd:YAG laser is almost-equal-to 14%.