Laser-induced dark traces in doped LiNbO3 crystals

Abstract

Laser-induced dark traces in doped LiNbO3 crystals are studied with the 1064 nm fundamental radiation and the 532 nm second harmonic radiation of the Nd:YAG laser operating in a pulse mode. The results show that the dark traces are induced only by the 532 nm radiation. The linear relationship between the transmission loss and the 532 nm power density indicates that dark traces are not due to two-photon absorption. The recovery rates of the absorption in LiNbO3 with different wavelength probe laser are measured and show that laser-induced dark traces accompany more than one defect appearing in LiNbO3, and disappear quicker at higher temperature.