LiNbO3-Tm3+ Crystal. Material for Optical Cooling

The possibilities of LiNbO3-Tm3+ crystals for optical cooling based on anti-Stokes luminescence in the wavelength range of 1818–2200 nm are investigated. The concentration dependences of the final temperature of the crystal have been determined under continuous (CW) excitation at wavelengths of 1822–1977 nm with a pump intensity Fp=5×1021 cm−2s−1. It was shown that significant cooling with ∆T = 22 K, 19 K, and 16.4 K can be achieved, respectively, with excitation at wavelengths 1977, 1967, and 1948 nm.