Spectral hole burning in naphthalocyanines derivatives in the region 800 nm for holographic storage applications
Persistent spectral hole burning is studied for several free-based and metallo-naphthalocyanine derivatives in polymer hosts. These materials exhibit a strong 0-0 absorption band in the region 800 nm matching the wavelength range of most semiconductor diode lasers and Ti:Sapphire lasers. Metallo-naphthalocyanines demonstrate a nonphotochemical hole-burning mechanism that is likely related to rotations of small molecular groups attached to a relatively rigid molecular ring. Free-base molecules exhibit the regular proton phototautomerization mechanism of hole burning. Spectral- and hole-burning parameters were determined for eight materials; in particular, the hole-burning kinetics was analyzed and the quantum efficiencies were determined to be between 0.1% and 1%. Holograms (data pages) in the transmission geometry were successfully recorded in the materials studied using single-frequency laser diodes.