Nonlinear Meta-Devices: From Plasmonic to Dielectric

Meta-devices have significantly revitalized the study of nonlinear optical phenomena. At the nanoscale, the detrimental effects of phase mismatching between fundamental and harmonic waves can be substantially reduced. This review analyzes the theoretical frameworks of how plasmonic and dielectric materials induce nonlinear optical properties. Plasmonic and dielectric nonlinear meta-devices that can excite strong resonant modes for efficiency enhancement are explored. We outline different strategies designed to shape the radiation pattern in order to increase the collection capability of nonlinear signals emitted from meta-devices. In addition, we discuss how nonlinear phase manipulation in meta-devices can integrate the benefits of efficiency enhancement and radiation shaping, not only boosting the energy density of the nonlinear signal but also facilitating a wide range of applications. Finally, potential research directions within this field are discussed.