Abstract: Methyl violet dyes doped polyvinyl membrane build phase grating under two branchs of coherent beams irradiation. While changing one branch the range of one coherent light, the growth and erasure process of the phase grating can be examined through monitoring the changes of first order diffraction light intensity. The theory and experimental results are provided.

Key words: methyl violet dyes doped polyvinyl membrane, phase grating, multi-holographic memory