Photochromic materials for holography: issues and constraints

Photochromic materials can find application in holography, thanks to the peculiar possibility to change reversibly their transparency in the visible (amplitude holography) and their refractive index in the near infrared region (phase holography). The main advantages of such materials are rewritability and self-development. A large change of the key property is crucial to obtain efficient devices and some strategies are followed, accordingly. Production of the holograms have open important issues regarding the film thickness and the nonlinear response to light, because of the strong absorption of the writing light by the material. Results related to these topics, mainly focused on diarylethene-based materials, are reported.