Experimental Comparison of the "AC Field" and "Moving Grating" Techniques for BTO and BSO Crystals

There are two techniques of nonstationary holographic recording which are widely used for PRCs with long drift lengths of photocarriers. These are recording of a moving interference pattern in an external DC electric field [1] and recording of a fixed pattern in an AC field [21. Both of them allow the efficiency of the drift mechanism of recording in the external electric field to be increased and the recorded hologram to be transformed into a shifted one. The theory [3] predicts equal efficiencies of two-wave energy exchange for these two techniques. In practice, the "moving grating" technique is traditionally employed for Bi12SiO20 (BSO), but for Bi12TiO20 (BTO), recording in an AC field is in common use. Recent investigations of holographic recording in semi-insulating GaAs:Cr (λ=1.06 μm) [4,5] have demonstrated remarkable superiority of the moving grating mechanism.