Near-infrared holographic photorefractive recording under applied electric field in undoped Bi$_{12}$TiO$_{20}$ sillenite crystal

TL;DR

This study investigates near-infrared holographic recording in undoped Bi12TiO20 crystals at 1064 nm, demonstrating a significant increase in diffraction efficiency under an applied electric field and analyzing the underlying charge carrier mechanisms.

Contribution

It provides the first detailed characterization of diffraction efficiency enhancement in Bi12TiO20 under electric fields at near-infrared wavelengths, with theoretical modeling and trap concentration estimation.

Findings

Diffraction efficiency increased 12-fold with electric field.

Theoretical model fit well with experimental data.

Effective trap concentration estimated at 5.3×10^{15} cm^{-3}.

Abstract

Direct holographic recording in undoped Bi$_{12}$TiO$_{20}$ crystal at 1064 nm is investigated aiming the characterization of diffraction efficiency under action of applied dc electric field ($E_0$). An enhancement of 12-fold in the diffraction efficiency was revealed when $E_0$ increased from 0.0 to 4.2 kV/cm. The theoretical dependence of the diffraction efficiency upon $E_0$ was investigated using the standard model for photorefractivity and the results showed a good experimental data fitting, allowing the computation of the effective trap concentration $(N_D$$)_{eff}$ $\approx$ $5.3\times 10^{15}$ cm$^{-3}$ which is responsible by the recording mechanism into the BTO crystal sample. The type of charge carrier involved in the recording mechanism in the nearinfrared region is also discussed.