Abstract

In holographic experiments performed for both chemical and physical investigations, chemical species modulation created in photochromic media is linked to the diffraction efficiency of the hologram, whereas the sensitivity of the media depends on the kinetic constant of the photochemical reaction. Numerical calculation have already been used to evaluate such quantities.¹ Moreover, kinetic constant have been evaluated by using the Kogelnik equations approximated for low time of exposure.² In this paper, exact equations describing the light intensity and molecular concentration of the reactive at any position in the layer and any time of exposure will be given for bleaching and blackening recording media, such as thionine polyvinylalcohol or dichromated gelatin. Theoretical curves will be given for the sinusoidal lightening pattern that is encountered in simple holographic experiments. The equations describing those curves should be used to calculate the modulation of the optical density and the refractive index in the medium. All evaluated values are related to molar absorption and molar refraction coefficients of the chemical reactive and product and to the quantum yield of the photochemical reaction.

© 1990 Optical Society of America