Optical limiting and theoretical modelling of layered transition metal dichalcogenide nanosheets

Abstract

Nonlinear optical property of transition metal dichalcogenide (TMDC) nanosheet dispersions, including MoS 2, MoSe 2, WS 2, and WSe 2, was performed by using Z-scan technique with ns pulsed laser at 1064nm and 532nm. The results demonstrate that the TMDC dispersions exhibit significant optical limiting response at 1064nm due to nonlinear scattering, in contrast to the combined effect of both saturable absorption and nonlinear scattering at 532nm. Selenium compounds show better optical limiting performance than that of the sulfides in the near infrared. A liquid dispersion system based theoretical modelling is proposed to estimate the number density of the nanosheet dispersions, the relationship between incident laser fluence and the size of the laser generated micro-bubbles, and hence the Mie scattering-induced broadband optical limiting behavior in the TMDC dispersions.