▎ 摘　　要

The optical limiting (OL) properties of single-layer graphene dispersions at 532 and 1064 nm wavelengths were investigated using a nanosecond laser. The experimental results show that the activating threshold of the single-layer graphene dispersed in chlorobenzene (CB) is lower than that of single-walled carbon nanotubes (SWNTs) by a factor of 10. The nonlinear scattering experiments for the graphene dispersions indicate that the main mechanism of the OL properties is nonlinear scattering effect, whereas nonlinear absorption might contribute to the OL effect of graphene in CB. To enlarge the damage threshold of the limiter, we propose a cascaded optical limiter by combining the advantages of low activating threshold for the graphene and the high damage threshold for the SWNTs. The cascaded optical limiter shows a low activating threshold, a high damage threshold, and broadband OL properties. (C) 2014 AIP Publishing LLC.