Optical Limiting and Theoretical Modelling of Layered Transition Metal Dichalcogenide Nanosheets.

Nonlinear optical property of transition metal dichalcogenide (TMDC) nanosheet dispersions, including MoS₂, MoSe₂, WS₂, and WSe₂, was performed by using Z-scan technique with ns pulsed laser at 1064 nm and 532 nm. The results demonstrate that the TMDC dispersions exhibit significant optical limiting response at 1064 nm due to nonlinear scattering, in contrast to the combined effect of both saturable absorption and nonlinear scattering at 532 nm. 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. [ABSTRACT FROM AUTHOR]