Substrate-Independent Light Confinement in Bioinspired All-Dielectric Surface Resonators

TL;DR

This paper introduces a bioinspired zigzag surface structure that supports substrate-independent optical resonances, enabling light confinement without the need for high index contrast, with potential applications in structural color and light guiding.

Contribution

The authors design and experimentally verify a novel all-dielectric surface resonator inspired by butterfly wings that maintains resonance modes independent of substrate properties.

Findings

Resonances are maintained without index contrast.

Experimental validation in the visible spectrum.

Potential for substrate-independent photonic applications.

Abstract

Traditionally, photonic crystal slabs can support resonances that are strongly confined to the slab but also couple to external radiation. However, when a photonic crystal slab is placed on a substrate, the resonance modes become less confined, and as the index contrast between slab and substrate decreases, they eventually disappear. Using the scale structure of the Dione juno butterfly wing as an inspiration, we present a low-index zigzag surface structure that supports resonance modes even without index contrast with the substrate. The zigzag structure supports resonances that are contained away from the substrate, which reduces the interaction between the resonance and the substrate. We experimentally verify the existence of substrate-independent resonances in the visible wavelength regime. Potential applications include substrate-independent structural color and light guiding.