Second harmonic generation in polycrystalline ZnS nanowaveguides

Abstract: We report the realization of Zinc Sulfide (ZnS) nanowaveguides and the experimental observation of second harmonic generation (SHG) in such structures, demonstrating their potential for integrated nonlinear photonics. ZnS thin films were deposited via RF magnetron sputtering and characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and ellipsometry. The nonlinear optical properties of these films were theoretically analyzed to assess their suitability for second-order nonlinear processes. We detail the fabrication and optical characterization of ZnS nanowaveguides, leading to the experimental observation of SHG in such structures. These findings establish ZnS as a promising platform for nonlinear photonic applications, particularly in compact and integrated frequency conversion devices. This work represents a significant step toward expanding the scope of wide bandgap semiconductors in advanced photonic technologies.