Two-photon absorption cross section for Coumarins 102, 153 and 307

Two-photon absorption cross sections of Coumarins 102, 153, 307 solutions in methanol in the wavelength range of 730-870 nm were measured. The maximum cross section for two-photon absorption in this wavelength range were 26±7, 36±9, 28±7 GM for Coumarins 102, 153, 307, respectively. The absolute value of the cross sections was determined by comparison with a fluorescein (43 GM at a wavelength of 790 nm). The dependence of the two-photon absorption cross section on the excitation wavelength coincides with the shape of the single-photon absorption cross section.