Few-Layer In₂Se₃ Nanosheets Applications in Photonics Logical Gate and Isolator

Indium selenide (In2Se3) is a novel van der Waals (vdW) layered two-dimensional (2D) materials, which are considered to possess strong nonlinear optical (NLO) characteristics and great potential for applications in nanophotonic devices. This paper aims to systematically study the NLO response of In2Se3 nanosheets by the spatial self-phase modulation (SSPM) technique. In2Se3 perform a strong nonlinearity effect at wavelengths of 457 nm, 532 nm, and 671 nm, respectively. Taking advantage of this effect, a logical gate based on In2Se3 is created to implement the OR function with a light-control-light system. Moreover, a nonlinear isolator, with based on the In2Se3/boron nitride hybrid sandwich structure, is designed to break the spatial reciprocity of optical transmission and achieve a unidirectional nonlinear optical response. We also confirmed the feasibility and reliability of the few-layer In2Se3 in the development of nanophotonic devices in all-optical signal processing technology that has enriched the application field of SSPM technique and the new 2D layered material. While it can be considered an important step for the application of new materials in the development of all-optical signal processing technologies.