Synthesis, characterization and two-photon absorption based broadband optical limiting in diarylideneacetone derivative

A donor-π-acceptor-π-donor (D-π-A-π-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 μm 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-π-A-π-D structure which allows for a greater extent of π electron delocalization due to a strong π-electron donor like thiophene.

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► Synthesis and characterization of D2TDO are reported. D2TDO film shows strong NLA in ns and fs regimes.
► The observed optical limiting in ns and fs regimes are due to two-photon absorption in the sample.
► Mechanism of NLA is found to be genuine 2PA arising due to the involvement of virtual intermediate states.
► Strong 2PA originates from the highly delocalized π electron density in the sample.
► With its broadband OL nature, D2TDO film can be used for eye and sensor protection applications.