Inverse Design of Nanoparticles for Enhanced Raman Scattering

TL;DR

This paper demonstrates that topology optimization can significantly improve the efficiency of surface-enhanced Raman scattering by designing novel metallic resonator structures that outperform traditional designs, approaching theoretical enhancement bounds.

Contribution

The study introduces a topology optimization approach for designing metallic resonators that achieve unprecedented Raman scattering enhancements, surpassing conventional structures.

Findings

Achieved ~100x improvement in SERS efficiency with optimized structures

Designed unconventional resonator geometries that outperform traditional antennas

Enhanced Raman scattering in complex configurations like coupled resonators

Abstract

We show that topology optimization (TO) of metallic resonators can lead to $\sim 10^2\times$ improvement in surface-enhanced Raman scattering (SERS) efficiency compared to traditional resonant structures such as bowtie antennas. TO inverse design leads to surprising structures very different from conventional designs, which simultaneously optimize focusing of the incident wave and emission from the Raman dipole. We consider isolated metallic particles as well as more complicated configurations such as periodic surfaces or resonators coupled to dielectric waveguides, and the benefits of TO are even greater in the latter case. Our results are motivated by recent rigorous upper bounds to Raman scattering enhancement, and shed light on the extent to which these bounds are achievable.