Fig. 1

One- and two-photon absorption spectra for ruthenium complexes. One- and two-photon absorption spectra for a [Ru(bpy)3]2+ and b [Ru(phen)3]2+ in H2O. The two-photon absorption cross section (red points) is shown as a function of the illuminating laser wavelength (lower horizontal scale). The corresponding one-photon molar absorption (blue solid lines) is shown at the 1PA wavelength (upper horizontal scale). Inserts show the permanent dipole moment change (black points) evaluated according to Eq. (1) at the long-wavelength side of the 2PA spectrum