New nonlinear optical crystal GdYCOB for noncritically phase-matched UV generation

Summary form only given. In previous work, we reported that yttrium calcium oxyborate YCa/sub 4/O(BO/sub 3/)/sub 3/ (YCOB), which was an isomorph of GdCOB, was phase matchable for third-harmonic generation (THG) of Nd:YAG laser by type I sum frequency mixing, and it possessed moderate optical nonlinearity, sufficient mechanical hardness, and nonhygroscopicity. Recently, we succeeded to grow a substitutional solid solution of Gd/sub x/Y/sub 1-x/Ca/sub 4/O(BO/sub 3/)/sub 3/ (GdYCOB) with uniform composition. We could achieve a noncritically phase-matching (NCPM) at room temperature for THG of Nd:YAG laser with this crystal at x=0.24.