Near-infrared holographic photorefractive recording under applied electric field in undoped Bi12TiO20 sillenite crystal

Abstract

Abstract Direct holographic recording in undoped Bi12TiO20 crystal at 1064 nm is investigated aiming the characterization of diffraction efficiency under action of applied dc electric field (E0). An enhancement of 12-fold in the diffraction efficiency was revealed when E0 increased from 0.0 to 4.2 kV/cm. The theoretical dependence of the diffraction efficiency and the holographic erasure time upon E0 was investigated using the standard model of Kukhtarev for photorefractivity and the results showed a good experimental data fitting in both cases, allowing the computation of the effective trap concentration (ND)eff ≈ 5.62 × 1015 cm−3 which is responsible by the recording mechanism into the crystal sample. In particular, the theoretical-experimental investigation using the holographic erasure time also allowed to determine others relevant parameters for Bi12TiO20 such as the diffusion transport length LD, the Maxwell relaxation time τ M , and the quantum efficiency Φ that can explain the relatively slow dynamics of photorefractive recording and erasure in near-infrared region. The type of charge carrier involved in the recording mechanism in the near-infrared region is also discussed.