Abstract

Photochemical hole burning (PHB) is a promising recording technology for ultra-high-density, wavelength-multiplexed optical data storage. In this paper we report the influence of the free energy change of the electron-transfer reaction on the reactivity of photon-gated PHB. The PHB is induced by an electron-transfer reaction using zinc tetraphenylporphine (ZnTPP) in the higher triplet state as a donor and a series of acceptors with various reduction potentials. We obtained a preliminary energy requirement for PHB. The wavelength-selective light was from a dye laser tuned around 590 nm. The gating light was a 465 nm line of an argon-ion laser in accordance with the triplet–triplet absorption band of ZnTPP. For benzylbromide (−2.34 eV) and chloroform (−1.89 eV), neither single-photon nor photon-gated PHB occurred; the parenthesized values are the calculated free-energy changes for the electron-transfer reactions. However, photongated PHB was observed for ethylbromide (−1.43 eV) and amylbromide (1.30 eV). These results indicate that the reactivity of photongated PHB depends on the free-energy change, and PHB does not occur in the highly exothermic region.

© 1990 Optical Society of America