Study on UV-light-induced absorption in LiNbO₃:Fe, Co crystal

In this paper, the temporary UV-light-induced absorption in LiNbO ₃:Fe, Co crystal is investigated for different UV intensities. It is found that the sensitizing process in LiNbO₃:Fe, Co can be considered as a combination of two sub-processes with different time constants. Based on the lattice structure and the photochromic mechanism of the material, the two sub-processes are suggested to arise from electron transfer from O^2- to Fe³⁺ through two paths with different distances. The two-colour recording experiment in LiNbO₃:Fe, Co is also preformed by using UV and green light as gating and writing beams respectively. High sensitivity is obtained in the recording, which is considered as the consequence of direct charge transfer from O^2- to Fe³⁺.