Croconium dye as a sensitizer of photothermoplastic holographic media for the near-IR region

This paper discusses the spectral and photoconductive properties of films based on a co-oligomer of glycidylcarbazole with additives of croconium dye in comparison with similar films with squarylium, merocyanine, and cationic polymethine dyes. It is concluded that croconium dye, like merocyanine dye, belongs to the electron-non symmetric organic dyes. The possibility of using croconines as sensitizers of photothermoplastic holographic recording media for the near-IR region is demonstrated for the first time. The lower holographic sensitivity of recording media with croconium dye by comparison with squarylium and merocyanine dyes is associated with the presence of deep traps for charge carriers, which are formed by the molecules of an intraionic dye and are liberated when heated in the process of development of the holograms. (C) 2008 Optical Society of America.