Broadband Spatial Self‐Phase Modulation in Black and Violet Phosphorus and Near‐Infrared All‐Optical Switching

Abstract Black phosphorus (BP) has attracted great research interest in nonlinear optics due to its anisotropic photoelectronic properties. As an allotrope of phosphorus, violet phosphorus (VP) has higher stability and desirable wide bandgap than BP, broadening the potential applications of phosphorus in optoelectronics. Herein, the nonlinear optical responses of layered BP and VP over broad spectral range from 405 to 1064 nm are investigated by the spatial self‐phase modulation (SSPM) method. These results show that both BP and VP exhibit excellent broadband SSPM effects. They all have large nonlinear susceptibility value (up to ≈ 10 −8 e.s.u.), except for a weaker value at the near‐infrared band. Moreover, the SSPM pattern formation time becomes significantly longer with increasing wavelength. Significantly, an all‐optical switching using a 532 nm beam to control a 1064 nm near‐infrared beam is realized based on the SSPM, which demonstrate that the nonlinear optical response of signal beam (1064 nm) can be improved by adjusting the intensity of controlling beam (532 nm). This study provides a fascinating foundation for future applications of phosphorus allotropes in broadband nonlinear photonics.