Nonreciprocal-Like Chiral Second-Harmonic Generation in a Chiral 3R-MoS<sub>2</sub> Metasurface.
basic_science · Level V
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- Record sourced from PubMed, PMID 41979222.
- Also identified by DOI 10.1021/acs.nanolett.6c00536.
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Abstract
Breaking reciprocity in nonlinear optics offers a unique approach for directional control of information processing. Here, we report for the first time a chiral 3R-MoS<sub>2</sub> metasurface that enables nonreciprocal-like chiral second-harmonic generation (SHG) via nonreciprocal circularly polarized (CP) absorption. The metasurface supports Mie resonances due to the high refractive index of 3R-MoS<sub>2</sub>. With CP incidence around the resonant wavelength on the top surface, right-handed circular polarization (σ<sub>+</sub>) absorption is significantly stronger than left-handed circular polarization (σ<sub>-</sub>), leading to chiral SHG with a circular dichroism (SHG-CD) of 62%. Reversing the incidence direction inverts the absorption contrast, yielding an SHG-CD of -71%. Physically, such an optical response originates from both the intrinsic <i>C</i><sub>3<i>v</i></sub> symmetry of 3R-MoS<sub>2</sub> and the structural chirality of the metasurface. Leveraging this property, we further demonstrate four optical logic operations, AND, OR, A ANDNOT B, and A ORNOT B, revealing the metasurface as a multifunctional, polarization-dependent platform for optical logic.