Abstract

We report the nonresonant and resonant excitation of the nonstationary holographic currents in an external sinusoidal electric field. Investigations of photocurrent excitation in an alternating electric field have shown that application of a high frequency electric field results in the nonresonant enhancement of the signal amplitude. This effect was observed for low frequencies of phase modulation ω < Ω where the influence of electric field with frequency Ω can be considered as “enhanced diffusion” of carriers recording the space charge distribution with large amplitude. The dependencies of the current amplitude and characteristic cutoff frequency versus applied voltage are utilized for the determination of the photocarrier’s µτ product. The second step was the investigation of the influence of an AC electric field on the nonstationary photocur-rent excitation for high frequencies of phase modulation (ω > Ω). We demonstrate that the frequency transfer function of the effect has a maximum originated from the resonant excitation of photo-conductivity gratings. The drift mobility of electrons is estimated from the position of the resonant peak on the frequency transfer function of the effect: 0.13 − 0.8 cm²/V s. The advantages of the photocurrent generation in ac fields are pointed out and possible practical applications of the effect are discussed.

© 2003 Optical Society of America