Associate Professor Atsushi Taguchi’s research group at Hokkaido University has discovered an optical antenna structure that selectively couples to the rotational direction of circularly polarized light (CPL). This three-dimensional nanostructure was designed using topology optimization, a high-degree-of-freedom design technique, and exhibits unique characteristics compared to conventional two-dimensional chiral structures. Furthermore, near-field analysis has revealed that the optical chirality carried by incident CPL is squeezed and localized at the nanoscale within the optical structure. This achievement provides a novel insight into nanoscale control of optical chirality and offers a design principle for efficient chiral nanostructures.
This research was published in Physical Review Applied on February 11, 2025.

https://doi.org/10.1103/PhysRevApplied.23.L021002