Azodye gelatin films for polarization holographic recording

Mordant pure yellow azodye in a matrix of gelatin is proposed as a medium f or stable polarization recording. Relatively high values of birefringence a re measured (over Deltan = 0.02). Polarization diffraction gratings are rec orded with two circularly polarized waves and diffraction efficiency of 67% is achieved at 633 nm. Protected from the humidity, the recording is stabl e. Long-term radiation by a 633 nm probe beam is harmless as well. Unusual behaviour is observed when acting on the recorded grating alternatively wit h one of the recording beams. The left circularly polarized beam erases the grating sharply, while the right circularly polarized beam, before erasure , initially increases the diffraction efficiency.