Infrared recording with gelatin films.

Gelatin films glued to an O-ring are proposed as a new procedure to record interference patterns when a CO(2) laser is used as an infrared light source. With this method the unwanted effects given by asubstrate, on which the thin recording film is laid, are avoided. To characterize the medium, interferometric studies including the recording of diffraction gratings have been done. Diffraction efficiencies of ~30% have been obtained when coherent red light (0.6328-microm wavelength) was sent normally to the gratings. An example of an infrared recorded hologram is shown.