Growth and Optical Properties of Yb:Ca3 (NbGa)5O12 Crystals by Bridgman Method.

Ytterbium ion doped calcium niobium gallium garnet crystal (Yb: Ca3 (NbGa)5 O12) was successfully grown by Bridgman method. The structure of the crystal was analyzed by XRD. The crystal is cubic crystal system, and the unit cell parameter a = b = c = 12.471 Å. The crystal was tested by Raman spectroscopy, transmission spectroscopy, absorption and emission spectroscopy, and fluorescence lifetime. The absorption cross section, emission cross section, and gain cross section of the crystal were calculated. The effects of annealing in air on the absorption spectrum, emission spectrum and fluorescence lifetime of the crystal were studied. The absorption cross section at 935 nm before annealing is 1.82 x 10-20 cm², and it decreases to 1.40 x10-20 cm² after annealing. The emission cross section at 1 031 nm before annealing is 0.56 x10-20 cm² and it decreases to 0.40 x 10-20 cm² after annealing. The fluorescence decay time before annealing is 1.42 ms, and it is 1.32 ms after annealing. The results demonstrate that the annealing of Yb:Ca3 (NbGa)5 O12 single crystal in air will adversely affect the laser performance of the crystal.Yb:Ca3(NbGa)5O12 crystal. [ABSTRACT FROM AUTHOR]