Predictions of Novel Two-Photon Absorption Bands in Fluorescent Proteins
journal contributionposted on 20.12.2007, 00:00 by Riccardo Nifosì, Yi Luo
By means of time-dependent density functional theory, we calculate the two-photon cross-sections for the lowest relevant excitations in some model chromophores of intrinsically fluorescent proteins. The two-photon strength of the first, one-photon active transition varies among the various chromophores, in line with experimental findings. Interestingly, additional transitions with large two-photon cross-sections are found in the 500−700 nm region arising from near-resonant enhancement, as revealed by few-state model analysis. Multiphoton excitation of fluorescent proteins in this spectral region can lead to relevant application for bioimaging.