Review of optically active and nonlinear chiral metamaterials

Abstract

Advanced photonic nanostructures have enabled the maximization of synthetic chiroptic activities. The unique structuring of these building blocks has empowered chiral selective interactions with electromagnetic waves in plasmonic structures and dielectric media. Given the repertoire of optimized chiral surfaces in the literature and the ubiquity of chirality in the organic realm, the natural direction to consider is the operation of these devices in larger optical systems much like their chiral organic counterparts. Here, we recapitulate advances in active and nonlinear chiral metamaterials. Many of the results, such as the magneto-chiral anisotropy and third-harmonic Rayleigh scattering optical activity, are relatively unknown members of the more conventional family of tuning methodology and nonlinear processes. We believe that they are poised to play an instrumental role in designing advanced chiroptic systems for applications in biochemistry, valleytronics, spintronics, and chiral quantum optics.

Nonlinear chiral metaphotonics: a perspective

“…Similar to linear effects, the enhancement of nonlinear chiroptical effects beyond the limit of natural material response can be achieved by engineering chirality at a macroscopic scale 25 – 28 What is different from the linear regime is that strong nonlinear optical activity also requires the high efficiency of nonlinear conversion. For this reason, resonances of metaphotonic structures are expected to play a crucial role, as they were shown to improve the frequency conversion efficiency dramatically by virtue of electric and magnetic hot spots enhancing the light–matter interaction 29 , 30 …”

Chiral Metasurfaces: A Review of the Fundamentals and Research Advances

“…Various geometries of metasurface have been investigated to optimize the chiroptical response, including nanorods [25][26][27][28][29], Slavic symbols [30][31][32], V-shaped nanoantennas [33][34][35][36][37][38], Yshaped meta-atoms [39][40][41], split-ring resonators [42][43][44][45][46], helix meta-atoms [47][48][49][50][51], twisted cross meta-atoms [52,53], multi-layered arc meta-atoms [54][55][56][57], and others that support optical resonances in subwavelength meta-atoms. Active chiral metasurfaces using optical, electrical, and mechanical methods have also been introduced to actively modify their chiroptical responses [9][10][11][58][59][60][61][62][63][64][65][66].…”

Active control of circular dichroism in a graphene–metal hybridized metamaterial driven by symmetry-protected bound states in the continuum

“…[13][14][15] Among them, chiral metamaterials are of great potential for pursuing outstanding chiroptical effects. In the past years, an increasing number of planar plasmonic 16 and dielectric 17 metamaterials have been demonstrated for strong chiroptical effects, which avoid complex fabrication processes compared to their counterparts with 3D nanostructures. 18,19 Apart from chirality, the Q factor is the other key parameter of chiroptical resonances, as it associates with the strength of chiral light-matter interactions.…”