Near-stoichiometric LiNbO3 (LiNbO3, LiNbO3:Tb, and LiNbO3:Tb,Fe) crystals have exhibited a reversible photochromic effect at room temperature. Irradiation by UV light induced a visible absorption band extending from λ≈650 nm to the absorption edge, which could be bleached by subsequent illumination with visible light. Electron paramagnetic resonance (EPR) analysis at 15 K revealed an EPR signal of g≈2.0 appearing after UV irradiation with a simultaneous decrease in the Fe3+ signal intensity. This implies that the Fe3+ ions (natural impurities or dopants) act as electron traps and the induced absorption band is caused by the charge transfer from UV-sensitive absorption centers to Fe3+ ions via the conduction band. Using the induced absorption band, a high-sensitive holographic recording has been achieved with a continuous-wave green laser at λ≈532 nm. In addition, the fast response to UV light made it possible to quickly erase the stored information by UV illumination.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)