Author/Authors :
Fakis، نويسنده , , Mihalis and Tsigaridas، نويسنده , , Georgios and Polyzos، نويسنده , , Ioannis and Giannetas، نويسنده , , Vassilis and Persephonis، نويسنده , , Peter and Spiliopoulos، نويسنده , , Ioakim and Mikroyannidis، نويسنده , , John، نويسنده ,
Abstract :
The intensity dependence of nonlinear absorption (NLA) of a series of pyrylium chromophores was studied with femtosecond pulses in their two-photon absorption spectral region to assess their potential as optical limiters. The open z-scan technique using different excitation intensities was employed. Fifth-order effects appear above a critical value of the irradiance and consequently of the first excited singlet-state population. Reverse saturable absorption (RSA) based on two-photon (TPA) and excited-state absorption (ESA) was dominant in most cases. The third- and fifth-order NLA coefficients and high ESA cross-sections of the order of 10−15 cm2 are presented at 760, 790 and 840 nm.
