Development of New Nonlinear Optical Crystal GdYCOB with Tunable Birefringence

Abstract

We have developed a new rare-earth calcium oxyborate crystal Gd_xY_<1-x>Ca_4O(BO_3)_3 (Gd_xY_<1-x>COB) in order to control the birefringence in nonlinear optical crystals. Gd_xY_<1-x>COB (0<x<1) crystals with uniform composition have been grown by the Czochralski method. The non-critical phase matching (NCPM) wavelength for second harmonic generation (SHG) has successfully been tuned in the range from 830 to 970 nm by changing the compositional parameter x. Furthermore, we have succeeded to generate NCPM third harmonic of Nd: YAG laser radiation (1064 nm)