Dielectric spiral nanoflower with a giant chiroptical effect (Conference Presentation)

Abstract

The chiroptical effect is a property that describes distinct response of matter to light with opposite handedness, which is extensively utilized in stereochemistry, analytical chemistry, metamaterials, and spin photonics. Conventionally, metallic nanostructures have been harnessed to generate a strong chiroptical effect with the assistance of surface plasmon resonance, but they usually suffer from low energy efficiency and large photothermal heat generation due to the high ohmic loss of metallic materials, which severely restricts their practical applications. Here we present a dielectric spiral nanoflower with a giant chiroptical effect produced by magnetic resonance. We theoretically predicted the giant chiroptical effect of the spiral nanoflower by numerical simulations and analyzed its underlying physics by combination of a multipole expansion method. Based on the theoretical design, we experimentally fabricated the spiral nanoflower and demonstrated its strong chiroptical effect by characterizing its circular intensity difference (CID). The largest-to-date CID of 35% is demonstrated. The magnetic quadrupole interference within the spiral nanoflower was also clarified by experimentally tailoring its magnetic quadrupole interference. Our work is expected to overcome the limitation of conventional metallic platforms and pave the way toward the development of various highly efficient and thermostable chiroptical devices and applications.