Document Abstract
Diffraction efficiency as a function of the applied electric field for the non-linear regime has been cal
culated by solving numerically the beam coupling equations. The refractive index variation used in the
beam coupling equations was calculated directly from the material rate equations via the total space
charge field. The diffraction efficiency of the holograms recorded in photorefractive media is not only
a function of the applied external electric field but also a function of crystal thickness, diffusion field,
reduced fringe contrast modulation ratio and absorption coefficient of the materials. The effects of these
parametersontheefficiencyofthehologramshavebeenstudiedindetails.Intheabsenceoftheexternal
applied field, it is found that the diffraction efficiency of the holograms could be maximized for a thin
ner photorefractive crystal having lower absorption coefficient and higher value of diffusion field, which
could exist at a much lower value of reduced fringe contrast modulation ratio of the index grating. More
efficient holograms can be recorded in the presence of the externally applied electric field as compared
to the case of no external field.