Nonlinear optical absorption of Sb2Se3: Dual response and [Sb4Se6]n ribbon orientation dependence

Abstract

The nonlinear optical (NLO) absorption response of Sb2Se3 polycrystalline film was systemically studied in this work. Both saturable absorption (SA) and reverse satuarable absorption (RSA) are found in Sb2Se3 polycrystalline film with short pulse and long pulse laser, respectively. The transient absorption spectrum of Sb2Se3 reveal the origin of dual NLO absorption response from the view of carrier dynamics. The dispersion of NLO absorption response of Sb2Se3 and its substrate dependence were also investigated in this work. By simulation of open aperture Z-scan data under the femtosecond laser excitation, the NLO absorption coefficient β and absorption cross section difference ∆σbetween ground state and excited state were calculated in spectral region of 700⁓860 nm. The NLO absorption response in these film samples were not only tuned by the excitation wavelength but also dependent on laser pulse width and their substrate. The wavelength-tailored, pulse width-dependent and substrate-dependent NLO properties allow them to be potentially applied in the field of photonics.