3D Metaphotonic Nanostructures with Intrinsic Chirality

Abstract

Chirality is a universal geometric property in both micro‐ and macroworlds. Recently, optical chiral effects have drawn increased attention due to their great potential in fundamental studies and practical applications. Significantly, the optical chiral response of artificial structures can be enhanced by orders of magnitude compared to that of their naturally occurring counterparts. These man‐made structures generally exhibit two types of optical chirality: extrinsic chirality and intrinsic chirality. The former relies on external illumination conditions, while the latter arises from the geometric characteristics of 3D objects. Herein, this review mainly focuses on the intrinsic chirality of artificial structures and discusses the existing realizations based on their design principles. In particular, an overview is given of the recent demonstrations of nonlinear optical effects in chiral structures and active chiral structures. Lastly, some promising prospects for future studies in the field are outlined.

Chiral Coupling of Valley Excitons and Light through Photonic Spin–Orbit Interactions

“…Remarkably, this extrinsic type of photonic SOI effects can be manipulated easily via tuning the material, position, size, and orientation of the subwavelength elements. It can be applied to achieve various optical functionalities by controlling the polarization, phase, amplitude, etc 112,114,164,165,168,171–175. For example, the propagation direction of a beam or SPP can be steered almost at will by using intentionally designed metasurfaces, as shown in Figure 6b,c.…”

“…It can be applied to achieve various optical functionalities by controlling the polarization, phase, amplitude, etc. [112,114,164,165,168,[171][172][173][174][175] For example, the propagation direction of a beam or SPP can be steered almost at will by using intentionally designed metasurfaces, as shown in Figure 6b,c.…”

Lithium Niobate Metasurfaces

“…Furthermore, metasurfaces enable optical functionalities unprecedented in the natural materials, such as anomalous refraction, and negative refractive index . Originally, the context of metasurfaces were discussed made of plasmonic metals, in which the collective oscillation of photon–electron modes confine electromagnetic energy and boost light–matter couplings, leading to giant chirality, enhanced nonlinearities, and high sensitive sensing . However, the intrinsic Ohmic losses hinder their applications.…”

Chiral Semiconductor Nanoparticles for Protein Catalysis and Profiling

“…Mechanistic investigations indicate the generation of hydroxylr adicals as the reactive species that cause the cutting of proteins.Chirality,which is usually based on organic molecules, [1] has been extended to inorganic nanomaterials such as metal nanoparticles (NPs), [2] carbon NPs, [3] semiconductor NPs, [4] ZnO films, [5] metaphotonic nanostructures, [6] NP assemblies with chiral geometries, [7] and so on. The anisotropyfactor of d/l-QDs was as high as 0.01.…”

“…Chirality,which is usually based on organic molecules, [1] has been extended to inorganic nanomaterials such as metal nanoparticles (NPs), [2] carbon NPs, [3] semiconductor NPs, [4] ZnO films, [5] metaphotonic nanostructures, [6] NP assemblies with chiral geometries, [7] and so on. [8] Chiral inorganic NPs have triggered great interest due to their easy synthesis and their tremendous applications including chiral sensing, [9] chiral separation, enantioselective catalysis,a nd advanced photonic devices.…”