Second-harmonic generations of blue light in nonlinear optical crystals of Gd_1−xLu_xCa_4O(BO_3)_3 and Gd_1−xSc_xCa_4O(BO_3)_3 through noncritical phase matching

Abstract

Nonlinear optical borate crystals of Gd1−xSCxCa4O(BO3)3 and Gd1−xLuxCa4O(BO3)3 have been grown and characterized. By changing the composition of these crystals, their optical birefringence can be controlled to obtain second-harmonic generations (SHG) in the ranges of 790-824 nm along the Y axis and 920-963 nm along the Z axis through noncritical phase matching (NCPM). The refractive indices of grown crystals were measured with a minimum-deviation technique. The experimental results of NCPM conditions for SHG are in good agreement with the theoretical predictions.