Resonance enhancement of two-photon absorption in porphyrins

Summary form only given. The goal of this paper is, first, to present the two-photon absorption (TPA) spectra in absolute cross section values (/spl sigma//sub 2/) for a number of porphyrins with gradually varying optical properties, and, second, to show that the TPA efficiency of these molecules can be resonantly enhanced in near-IR region. TPA spectra were obtained by tuning an optical parametric amplifier.