Nonlinear optical response, all optical switching, and all optical information conversion in NbSe2 nanosheets based on spatial self-phase modulation

Abstract

An efficient liquid phase exfoliation method has been developed for the preparation of high quality NbSe₂ nanosheets. The pure nonlinear optical properties of these nanosheets have been investigated using three different wavelength continuous wave (CW) lasers. The spatial self-phase modulation (SSPM) effect can be observed clearly in solution dispersions of (NbSe₂). The experimental data show that the diffraction is caused by the third-order optical nonlinearity of NbSe₂. The third-order nonlinearity susceptibility χ⁽³⁾ of NbSe₂ is about 10⁻⁹ e.s.u. by analyzing the experimental results. The relaxation time in the dynamic relaxation is about 1.38 s, 1.58 s, and 1.15 s for 532 nm, 671 nm, and 457 nm, respectively. In addition, the realization of all-optical switching based on SSPM, particularly two-color intrachromatic coherence, indicates that the generation of electron coherence is a universal characteristic of layered quantum materials. All optical information conversion based on the SSPM is also confirmed experimentally. Our experimental results have simple potential application prospects for NbSe₂ based on its nonlinear optical response.