Two-dimensional Bi ₂ S ₃ -based all-optical photonic devices with strong nonlinearity due to spatial self-phase modulation

Abstract

Abstract Bismuth sulfide (Bi 2 S 3 ) is a binary chalcogenide semiconductor compound that has received much attention in optoelectronic devices because of its stratified structure. In this work we showed that the two-dimensional (2D) Bi 2 S 3 shows strong nonlinearity using spatial self-phase modulation and that the all-optical photonic devices, e.g. the all-optical switches and all-optical diodes, have been demonstrated experimentally by observing the nonlinear behavior of the diffraction rings. In addition, an all-optical diode is designed in this work using combined structure with 2D Bi 2 S 3 /SnS 2 nanosheet by taking advantage of the reverse saturated absorption of 2D SnS 2 and saturated absorption of 2D Bi 2 S 3 . Nonreciprocal light propagation has been achieved with different incident wavelength and a variety of incident intensities. Those characteristics make 2D Bi 2 S 3 a potential candidate for the next generation nonreciprocal all-optical device.