Ti₃C₂ nanosheet is a newly discovered two-dimensional (2D) clan. It turns out to have encouraging applications for electromagnetic shielding and energy storage. Here, Ag@ Ti₃C₂ hybrids are precisely synthesized by using the one-step solution processing method. Also, their ultrafast broadband nonlinear optical responses in the visible region are studied systematically through nanosecond open-aperture Z-scan and transient absorption techniques. The mechanism of two-photon absorption (TPA) is disclosed in the visible region (409–532 nm). When the laser energy is low and the wavelength is longer than 400 nm, nonlinear absorption cannot happen. Meanwhile, as the laser energy increases, two photons will be absorbed by the electrons in the valence band and the electrons will jump to the conduction band. The process is named as two-photon absorption which will make the specimen show reverse saturable absorption (RSA) properties. What is more, the ultrafast carrier dynamics of the specimen are studied by using the transient absorption. The result shows that the decay contains two phases: the fast and then the slow one. The two phases first come from electron–phonon and then from phonon–phonon interactions, respectively. The electron transfer and charge carrier trapping processes are further verified by the outcomes of similar measurements on Ag@ Ti₃C₂ hybrids. Besides, the two decay processes increase together with the pump fluence. These results show that Ti₃C₂ nanosheet has potential applications in broadband optical limiter.

Two-dimensional self-similar azimuthons are introduced and investigated analytically and numerically in nonlocal nonlinear media with space-dependent diffractive, gain (attenuation) coefficient based on the similarity transformation and variational approach.We demonstrate that the azimuthons of critical power in the strongly nonlocal limit are more stable than the ones with lower nonlocality. Remarkably, these self-similar azimuthons have the azimuthal angle modulated by the distributed diffractive coefficient, apart from the beam width and intensity changing self-similarly.

A Kerr-type nonlinear system of two incoherently coupled components with spatially inhomogeneous nonlinearity is discussed by means of separation of variables. The hierarchies of analytical as well as numerical constructed vector vortex solitons with higher topological charge ( S ≥ 2) are generated. Some basic properties of solutions like the existence, appearance, the effective diameter are studied. The stability of obtained vector vortex solitons are predicted by small disturbance analysis and confirmed by direct simulation. Some thresholds of propagation constant supporting stable vector vortex solitons are given.