Un mal au cœur fébrile

As a wide-bandgap oxide group II–VI semiconductor with a direct energy gap of about 3.37 eV, zinc oxide (ZnO) finds potential applications in the fabrication of next-generation optoelectronic devices. Nonlinear optical phenomena are becoming increasingly important as diagnostics for a wide range of physical properties, and nonlinear optical materials exhibit important functions in photonic technology. Many components of next-generation optical communications systems, optical sensing, and materials research rely on nonlinear optical processes. Understanding of nonlinear behavior of induced polarization and analyzing and controlling its impact on light propagation through materials are important in nonlinear optics. Single-beam Z-scan technology is one of the most effective technologies for studying nonlinear optical behavior of materials. This article discusses the specific nonlinear optical properties of ZnO nanostructures and their composites, such as nonlinear absorption, refraction, optical switching, and optical limiting, by focusing on the fundamental concepts of nonlinear optics and the Z-scan technique. Based on these findings, it is reasonable to conclude that ZnO and its composites are excellent nonlinear optical materials for use in a wide range of photonic devices.