Diffraction analysis of photoanisotropic holography: An anisotropic saturation model

The photoisomerization of a highly anisotropic dye molecule depends not only on the intensity but also on the polarization state of the acting light with respect to the molecular axis. Polarization-dependent isomerization of uniformly oriented distributions of anisotropic dye molecules produces an orientational distribution of photoexcited states. Saturation occurs when all the molecules aligned in a particular orientation are isomerized so further photoexcitation cannot occur. This anisotropic saturation occurs first in the direction aligned with the incident polarization. We investigate this anisotropic saturation behavior and present a theoretical model that incorporates intensity saturation for describing holographic diffraction in dynamic photoanisotropic organic materials. Numerical simulations of diffraction versus intensity and polarization are provided and compared with the experimental results. (C) 1996 Optical Society of America