Chiroptical Enhancement in Hybrid Core–Shell Nanoresonators

The interaction between chiral light and matter in metamaterials has introduced a significant paradigm in modern optics. While plasmonic metamaterials exhibit robust localized electric field enhancement, their ability to enhance magnetic fields is somewhat limited. Conversely, dielectric metamaterials can achieve simultaneous enhancement of electric and magnetic fields at comparable resonance frequencies, offering advantages such as minimal loss and weak thermal effects. In this work, we propose a metasurface structured with a core–shell configuration based on a hybrid material system and explore the interplay between superchiral optical fields and the matter within it. By manipulating the dimensions of the structure, we can achieve spectral alignment of electric and magnetic resonances within the core–shell architecture. When the phase conditions are satisfied, distinctively enhanced electric and magnetic fields distributed separately, culminating in the creation of superchiral hotspots. This enhancement is further magnified through the coupling interactions between adjacent lattice units. With resonance chiral molecules adsorbed onto the spacer layer, the circular dichroism (CD) signal of the coupled system experiences a remarkable boost by a factor of 79.4. We demonstrate that, in this context, the overall signal predominantly emerges from the intrinsic CD signal of the molecules, offering a direct reflection of the characteristics of the investigated sample. These findings are poised to establish an innovative platform for chiral optical applications.