高质量CdSe单晶生长及其OPO性能研究

High quality CdSe single crystal, with the sizes of 54 mm in diameter and 25 mm in length, was successfully grown by a high pressure vertical gradient freeze (HPVGF) technique using seed. The full width at half maximum (FWHM) of (002) and (110) X-ray rocking curves of the CdSe crystal with wurtzite structure are 54.4 arcsec and 45.6 arcsec respectively. The results show that there are some small-size Se inclusions in CdSe crystal by the test of infrared microscope and SEM-EDS. The transmission spectra show that the infrared transmission is above 68% and the mean absorption coefficient is 0.037 cm^-1 in the range of 2.5-20 μm. Using fabricated type II CdSe crystal with the dimensions of 10 mm×12 mm×50 mm, we demonstrated an optical parametric oscillator (OPO) pumped by a 2.09 μm acoustooptic Q-switched Ho: YAG laser at a pulse repetition frequency of 1 kHz. Up to 389 mW output is obtained at the idler wavelength of 11.47 μm with a linewidth of 33.2 nm.