摘要
A donor-蟺-acceptor-蟺-donor (D-蟺-A-蟺-D) type Bis-Chalcone, (1E,4E)-1,5-di-2-thienylpenta-1,4-dien-3-one (D2TDO) was synthesized by Claisen-Schmidt reaction. Structural characterization was done with the help of UV, FT-IR, 1H NMR, 13C NMR and Mass Spectroscopic techniques. Through gravity settling method, a homogenous film of D2TDO with 65 渭m thickness was made in poly(methylmethacrylate) matrix. The third-order absorptive nonlinearity and resultant optical limiting behavior of the D2TDO film were studied by employing open aperture z-scan method in both nanosecond and femtosecond excitation regimes. Through numerical simulations, the mechanism of nonlinear absorption was found to be a two-photon absorption process with broadband response. The optical limiting performance of the molecule has its origin from the molecule's peculiar D-蟺-A-蟺-D structure which allows for a greater extent of 蟺 electron delocalization due to a strong 蟺-electron donor like thiophene.