Theoretical and experimental analysis of overmodulation effects in volume holograms recorded on BB-640 emulsions

Kogelnik's coupled-wave theory has provided a well-established basis for understanding how light propagates inside a volume hologram, giving an accurate approximation of the diffraction efficiency in this type of hologram. In this paper we elaborate on some aspects of the theory. In particular we evaluate the effects of an overmodulation of the refractive index inside the hologram, which results in a particular behaviour of the angular response of the diffraction efficiency. These overmodulation effects are found when fixation-free holograms are recorded on silver halide emulsions.This study was supported by the "Comisión Interministerial de Ciencia y Tecnología (CICYT)" of Spain under project Nº MAT2000-1361-C04-04