Linear and nonlinear absorption properties of hemicyanine dyes containing 5-(4H)-oxazolone as heterocyclic ring

Abstract

A series of dyes containing electron-donating (D) and electron-accepting (A) groups connected through a π-conjugated linker were designed and their linear and nonlinear absorption properties were studied. The dyes combined 1,3-oxazol-5(4H)-one core with methoxy, methyl, phenyl, cyano, and nitro group in the para-position of a phenyl ring. Spectrally resolved two-photon absorption cross-section measurements carried out by the femtosecond Z-scan technique showed wide wavelength regions of nonlinear optical absorption. The studied compound containing the phenyl ring exhibits relatively high effective two-photon absorption cross-section equal to 772 ± 100 GM at 600 nm. The experimental optical characterization is supported by the results of electronic-structure calculations.