Power--bandwidth limitations of an optical resonance

TL;DR

This paper establishes fundamental upper limits on the power--bandwidth product for a single optical resonance, depending solely on material susceptibility, and explores how to design multiple scatterers for broadband response.

Contribution

It introduces shape-independent upper bounds for the power--bandwidth product in optical resonances and applies these limits to design broadband scatterers.

Findings

Quasistatic metallic scatterers can nearly reach the theoretical limits.

The approach enables designing multiple scatterers for flat, broadband optical response.

Limits depend only on material susceptibility, not shape or size.

Abstract

We present shape-independent upper limits to the power--bandwidth product for a single resonance in an optical scatterer, with the bound depending only on the material susceptibility. We show that quasistatic metallic scatterers can nearly reach the limits, and we apply our approach to the problem of designing $N$ independent, subwavelength scatterers to achieve flat, broadband response even if they individually exhibit narrow resonant peaks.