Crystal diffraction grating in LiNbO3:Fe derived from interferometric volume holography

A 90 deg two-beam coupling configuration was used to store an image of an extended object in a 0.032%wt iron-doped LiNbO3 crystal. A volume hologram was thus generated, via the photorefractive effect, within the microstructure of the crystal. The time evolution of partial spatial erasure of the hologram under illumination was studied by capturing its reconstructed image on a digital camera and performing a two-dimensional inverse Fourier transform. This produced the refractive index grating created through interference of object and reference beams. The nature, intensity distribution and dimensions of the diffraction grating were derived in order to throw light upon the movement and mechanisms of charges, which create the index grating.