Large Optical Nonlinearity Enhancement and All-Optical Logic Gate Implementation in Silver-Modified Violet Phosphorus

As the most stable allotrope of phosphorus, violet phosphorus (VP) has attracted extensive research in the field of all-optical modulation due to its excellent broadband spatial self-phase modulation (SSPM) effect. To better exploit the great potential of VP in nonlinear photonics devices, this work explores chemical doping method to artificially enhance the nonlinear optical response of VP. Herein, silver-modified few-layer VP (Ag-VP) is constructed for SSPM experiments. In comparison to pristine VP, a significantly improved third-order nonlinear susceptibility (χ⁽³⁾) and nonlinear optical response for Ag-VP is obtained in visible light band, and the enhancement ratio increases with the increase of wavelength. Moreover, the excitation threshold of SSPM effect is also significantly reduced, with a reduction ratio up to 3.61. The enhanced nonlinear optical response is attributed to the improved light–matter interaction induced by impurity energy levels. By taking advantage of the outstanding SSPM effect of Ag-VP, an all-optical logic gate is designed to demonstrate “OR” logical information transmission. This work provides a new avenue for the design and application of energy-saving and tunable nonlinear photonic devices in the future.