Effect of infra-red irradiation on holographic recording in Bismuth silicon oxide

In this paper we discuss the effect of preliminary infrared (IR) irradiation on holographic recording in Bi₁₂SiO₂₀. The lighting has been found to give rise to an unusual dynamics of the diffraction efficiency. The diffraction efficiency of the hologram, recorded in the preliminary illuminated sample at low spatial frequencies (up to 1500 lines/mm) is eight times higher than that of the hologram, recorded without preliminary IR irradiation. At high spatial frequencies above 2000 lines/mm this additional lighting leads to an increase of the holographic sensitivity.