Photochemical hole-burning in a protonated phthalocyanine with GaAlAs diode lasers

The photochemical hole-burning properties of protonated free-base phthalocyanine molecules in concentrated sulfuric acid glasses at 8300 Å have been measured using GaAlAs diode lasers. We find a homogeneous width at 1.20 K of 1.00 ± 0.06 GHz that is substantially larger than the lifetime-limited value, and a power law temperature dependence of the homogeneous width with exponent 1.8 ± 0.1. © 1985.