Author/Authors :
Drobizhev، نويسنده , , M. and Karotki، نويسنده , , A. and Kruk، نويسنده , , M. and Krivokapic، نويسنده , , A. and Anderson، نويسنده , , H.L. and Rebane، نويسنده , , A.، نويسنده ,
Abstract :
We study the porphyrin S1→S0 fluorescence and the photosensitized singlet oxygen 1Δg→3Σg phosphorescence, both originating from absorption of photons with energy less than the porphyrin S0→S1 transition energy. By measuring the excitation intensity dependence of fluorescence at lowered sample temperatures, we are able to discriminate between two parallel processes of one-photon hot-band absorption (HBA) and simultaneous two-photon absorption (TPA). When the HBA and TPA contributions are comparable in magnitude, we use this new method to determine absolute TPA cross-section. We also demonstrate for the first time a singlet oxygen photosensitization via HBA in porphyrin.
