Multi-wavelength holographic storage in PMMA film containing spirooxazines

Holographic gratings were recorded in spirooxazine doped PMMA films by blue-violet laser (405nm), Nd:YAG laser (532nm) and He-Ne laser (632.8nm), respectively. It was found that the photo-dynamics of the holographic grating was dependent on recording wavelength for the photochromic characteristics of spirooxazines. A theoretical description of orientation and isomerization gratings agrees well with the experimental results. It was also found that a pure isomerization grating is formed by two interferential 405nm beams while a mixed grating consisting of isomerization and orientation components is formed by the visible interferential beams (532nm or 632.8nm). Due to the long life of the isomerization gratings, the holographic interference fringes with different periods were clearly observed by Confocal Laser Scanning Microscope.