Strong non-linear optical response of Sb ₂ Se ₃ nanorods in a liquid suspension based on spatial self-phase modulation and their all-optical photonic device applications

The field of nonlinear optics is constantly expanding and gaining new impetus through the discovery of fresh nonlinear materials. Herein, for the first time, we have performed spatial self-phase modulation (SSPM) experiments with an emerging anisotropic Sb₂Se₃ layered material in a liquid suspension for an all-optical diode and all-optical switching application. The third-order broadband nonlinear optical susceptibility (χ(3)single layer ∼ 10^-9 esu) and nonlinear refractive index (n₂ ∼ 10^-6 cm² W^-1) of Sb₂Se₃ have been determined using a 671 nm laser beam. This result could be unambiguously explained by the anisotropic hole mobility of Sb₂Se_3. The linear relationship of χ⁽³⁾ and carrier mobility emphasizes the establishment of nonlocal hole coherence, the origin of the diffraction pattern. Consequently, the time evolution of diffraction rings follows the 'Wind-Chime' model. A novel photonic diode based on Sb₂Se₃/SnS₂ has been demonstrated using the nonreciprocal propagation of light. The self-phase modulation (SPM) technique uses laser lights of different wavelengths and intensities to demonstrate the all-optical logic gates, particularly OR logic gates. The exploration of nonlinear optical phenomena in Sb₂Se₃ opens up a new realm for optical information processing and communication. We strongly believe that this result will help to underpin the area of optical nonlinearities among its various applications.