Can photonic heterostructures provably outperform single-material geometries?

TL;DR

This paper develops a theoretical framework to bound the performance of photonic heterostructures, enabling comparison with single-material systems and guiding design for superior electromagnetic objectives.

Contribution

It introduces a novel method to establish performance bounds for multilayer and multi-material photonic structures, extending optimization insights beyond single-material limitations.

Findings

Limits align with topology-optimized geometries

Heterostructures can outperform single-material designs

Performance bounds are within a factor of two of specific designs

Abstract

Recent advances in photonic optimization have enabled calculation of performance bounds for a wide range of electromagnetic objectives, albeit restricted to single-material systems. Motivated by growing theoretical interest and fabrication advances, we present a framework to bound the performance of photonic heterostructures and apply it to investigate maximum absorption characteristics of multilayer films and compact, free-form multi-material scatterers. Limits predict trends seen in topology-optimized geometries -- often coming within factors of two of specific designs -- and may be exploited in conjunction with inverse designs to predict when heterostructures are expected to outperform their optimal single-material counterparts.