Generation of 320 mW at 10.20 μm based on CdSe long-wave infrared crystal

CdSe single crystal, with the sizes of similar to 54 mm in diameter and similar to 25 mm in length, was grown by a high pressure vertical gradient freeze (HPVGF) technique using (0 0 1)-oriented seed. The CdSe crystal was characterized with transmission spectrophotometer. The transmission spectra showed that the infrared transmission was above 68% and the mean absorption coefficient was 0.041 cm(-1) in the range of 2.5-20 mu m. Using fabricated CdSe crystal with the dimensions of 6 mm x 10 mm x 44 mm, we demonstrated an optical parametric oscillator (OPO) pumped by a 2.05 mu m Ho:YLF laser at a pulse repetition frequency of 5 kHz. Up to 320 mW output was obtained at the idler wavelength of 10.20 mu m with a pump power of 18.06 W. 320 mW at 10.20 mu m, to our knowledge, was the highest power obtained with a 2.05 mu m laser-pumped CdSe OPO. (C) 2018 Elsevier B.V. All rights reserved.