Thick-layered light-sensitive dichromated gelatin for 3D hologram recording

A new method of 3-D image recording, so-called reference-free selectogram is considered. According to this method, the object wave is split into two parts with the help of a diffraction grating. The pattern originated from the interference of these components must be recorded in a thick-layered light-sensitive material that is positioned just behind the grating. Gel-like thick-layered dichromated gelatin has been suggested for the selectogram recording. In this case, the layer represents a gel of dichromated gelatin that is sealed between two glasses. The thickness of layers varied from 1 to 3mm. Holograms are recorded in such a material immediately during the process of exposure. The experimental data on the dependence of the diffraction efficiency on the exposure and the data on the dependence of the diffraction efficiency on the spatial frequency of the recorded grating are presented. The angular selectivity of the holograms recorded in the layers was about 10' The experiments have shown that the lifetime of the hologram recorded in gel-like gelatin is measured by several hours. The experiments on the recording of the reference-free selectogram were carried out. To compensate the low value of the sensitivity of the material, the selectograms were recorded when concentrating the light on a small area of the layer during the exposure.