CC BY
16LS-O-3
Progress on self-frequency-doubled Nd:Ca4GdO(BO3)3 and Yb:Ca4YO(BO3)3 crystal
H. Yu1, H. Zhang1, J. Wang1, Z. Hu2 1Shandong University,
State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Jinan, China 2Tianjin University of Technology, Institute of Functional Crystal Materials, Tianjin, China
Self-frequency-doubled (SFD) Nd:Ca4GdO(BO3)3 (Nd:GdCOB) and Yb:Ca4YO(BO3)3 (Yb:YCOB) crystal with different doping concentration has been grown by the Czochralski method. The thermal and fluorescence spectroscopic properties of Nd:GdCOB and Yb:YCOB crystals were studied. It was found that a dualwavelength laser output of 1060 and 1091 nm were obtained when pumped by the high power with Nd:GdCOB crystal. On the basis of Boltzmann Statistics, the number of electrons of lower level reduced with the increasing of the upper level, and the gain of 1060 nm decreased with the increase in the level of 1091 nm, leading to the increasing output of 1091 nm and the reducing output of 1060 nm. By optimizing the coating condition, the maximum output power of 3.01W at a wavelength of 545nm with an optical efficiency of 20.7% was obtained. The polarized fluorescence spectra with Yb:YCOB crystal showed that it had broad and anisotropic vibronic emission with a small peak at about 1130 nm. A watt-level self-frequency-doubled yellow laser at the 570 nm wavelength was realized by taking advantage of the vibronic emission of Yb:YCOB crystal cut along the optimized direction out of the principal planes with the maximum effective nonlinear coefficient. By employing the self-frequency-doubling behavior of Yb:YCOB, the self-frequency-doubled yellow laser was achieved with a maximum output power of 1.08 W at 570 nm.
