Nonlinear Optical Absorption Properties of Sputtered WSe2 Thin-films in the Near-Infrared Spectral Band.

We present a detailed investigation on the intensity dependent third-order nonlinear optical (NLO) properties of RFsputtered WSe2 thin film using ultra short pulses. The investigation employed a single-beam Z-scan technique using nearinfrared (NIR) ultra short pulses centered at 1030 nm for ascertaining the NLO response. The results reveal a reverse saturable absorption (RSA) signature, which is primarily due to the contribution from two-photon absorption (TPA). We explored the impact of high optical fluence on the TPA process and observed the weakening of the nonlinear optical absorption in WSe2 thin film, which essentially pointed towards a significant contribution of free-carriers as well as bandfilling effect. This research elucidates the insight of photophysical properties of WSe2 thin films and shows the potential use as optical limiters. [ABSTRACT FROM AUTHOR]