In this paper, we investigate the third-order nonlinearities and optical limiting effect of Tm: YAG crystal at a wavelength of 1064 nm. We experimentally measure different energy densities (6.4, 12.8, and 19.2 J / c m 2 ) and obtain the nonlinear absorption coefficient, nonlinear refractive index, and third-order nonlinear susceptibility of Tm: YAG crystal. Z-scan results show that Tm: YAG crystal exhibits a large nonlinear absorption coefficient ( 3.34 × 1 0 − 9 m / W ) at the wavelength of 1064 nm. We also measure the transmittance of Tm: YAG crystals of three different lengths (7, 15, and 20 mm) to evaluate its nonlinear optical limiting performance. For the 20 mm Tm: YAG crystal, the maximum transmittance without optical limiting effect and minimum transmittance with nonlinear optical limiting effect at a 1064 wavelength nm are 84.2% and 47.8%, respectively, which indicates that Tm: YAG crystal may be a solid material for nonlinear optical limiting at 1064 nm.

We study the nonlinear optical limiting effect of graphene dispersions in ethanol and acetone at a wavelength of 1064 nm. The nonlinear optical limiting effect of graphene dispersion under three different linear transmittances (about 70%, 80%, and 90%), two different thicknesses (1 and 3 cm), and two different solvents (ethanol and acetone) are measured. The influences of concentration, thickness, and solvent on the nonlinear optical limiting effect of the graphene dispersion are analyzed. The experimental results show that the concentration and solution thicknesses have great influence on the optical limiting ability of graphene dispersions. The graphene dispersions with ethanol and acetone as solvents can be used to achieve excellent nonlinear optical limiting effects. The optical limiting ability of the graphene dispersion in acetone is better than that of the graphene dispersion in ethanol.

A novel infrared broadband nonlinear optical limiting (NOL) technology based on stimulated Brillouin scattering (SBS) in As 2 Se 3 fiber is proposed. The As 2 Se 3 fiber allows a weak infrared laser to pass through, but blocks an intense laser with the same wavelength due to the SBS effect. This NOL technology has been experimentally proved to have excellent NOL performance for incident pulsed lasers with a typical infrared wavelength of 3.6 μm. The linear transmissions of 1 m and 0.5 m As 2 Se 3 fibers are higher than 90%, and the lowest nonlinear transmissions are reduced to 0.89% and 1.23%, respectively.