Remarkable temperature-dependent second-harmonic-generation performance of a YCOB crystal

For the first time, the temperature stability of second-harmonic-generation (SHG) is reported for the entire space of a YCa4O(BO3)(3) (YCOB) crystal for a temperature range of -10- 520 degrees C. Both theoretical calculations and experimental data indicate an optimum phase-matching (PM) direction of (theta =149.2 degrees, phi = 0 degrees), which is located in the XZ principle plane (90 degrees < theta < 180 degrees). A special regression phenomenon of the PM angle was found in this direction, which further increased the SHG output at high temperature (> 200 degrees C). As a result, for SHG of the Nd:YAG laser, the measured temperature bandwidth of a YCOB crystal cut along the optimum PM direction is larger than 490 degrees C.cm. As demonstrated in this study, among all nonlinear optical crystals, this cut-type is currently the best choice when temperature-insensitive SHG is required. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement