Strongly-coupled meta-atoms for extreme optical properties
(Left) Unnaturally high refractive index metamaterial operating at THz frequencies (Right) Capacitively coupled meta-atom structure designed for extremely large effective permittivity. Images adapted from the paper published in Nature (2011)
Seen from the perspective of conventional optics, the collection of artificially-structured atoms has enabled the observation of a vast variety of unexpected physical phenomena. Research activities of our group were focused on experimentally demonstrating extreme effective material (optical) parameters, such as large refractive index and strong chirality. For this purpose, we made use of meta-atom or meta-molecule structures that maximally utilize capacitive coupling between nearest neighboring meta-units. This approach made it possible for us to demonstrate record-high values of effective refractive index and chirality that have not been observed previously.
Key achievements: Proposal on the utilization of strong capacitive coupling between adjacent meta-atoms for realizing extreme effective material parameters (M. Choi et al., Nature, 2011, Y. Kim et al., Nature Photonics, 2016).