High-order photobleaching of pyrylium salts under two-photon excitation

Pyrylium salts were found to be attractive candidates for applications based on two-photon absorption effect. Especially, they have been used for three-dimensional data storage through photobleaching process. In the present work the photobleaching, under two-photon excitation, is investigated for a representative pyrylium salt hosted in a polymethylmethacrylate film. The photobleaching dependence on time, power and wavelength irradiation as well as on the film concentration is presented. Our results reveal the existence of two photobleaching mechanisms and indicate the presence of high-order interactions in these processes.