Anisotropy of nonlinear optical properties in monoclinic SmxY1-xCa4O(BO3)(3) crystals

The angular noncritical phase matching (A-NCPM) second-harmonic-generation (SHG) properties of SmxY1-xCOB (x = 0, 0.44, 0.55 and 1) nonlinear optical (NLO) crystals were investigated. The type-I A-NCPM SHG wavelengths along the Y and Z axes were found to be tunable in the ranges of 725-900 nm and 826-1116 nm, respectively, by adjusting the ratio of the rare-earth elements Sm and Y in SmxY1-xCOB crystals. Taking advantages of the fundamental laser pulses generated from a mode-locked Ti:Sapphire laser and a long Y-cut Sm0.44Y0.55COB crystal sample, the single-pass SHG average output power of similar to 436 mW at 397 nm was obtained with a conversion efficiency of 41.5%. In addition, the SHG phase-matching (PM) curve and the effective NLO coefficients (deff) of SmCOB crystal for 1064 nm laser were studied, where the optimal type-I SHG PM direction in principal planes was determined to exist in the XY principal plane i.e. (90 degrees, 52.4 degrees), rather than the ZX plane i.e. (theta degrees, 180 degrees), which was different with those of TmCOB (32.5 degrees, 180 degrees), YCOB (30.7 degrees, 180 degrees), TbCOB (22.6 degrees, 180 degrees), GdCOB (19.7 degrees, 180 degrees) and LaCOB (15.1 degrees, 180 degrees) crystals in the same crystal family. (C) 2018 Elsevier B.V. All rights reserved.