Ultrafast induced excited state absorption in organically doped xerogels Original Research Article

Vanadyl-phthalocyanines have been trapped in different silica-based xerogel matrices. Nonlinear `reverse saturable absorptionʹ behavior has been observed for femtosecond and nanosecond pulse excitation at 620 nm. Nanosecond experiments could be fitted using a classical 3-energy-level model. However, the time scales are such that the behavior observed with femtosecond pulses cannot be correctly interpreted with the same model.