Full conversion of unpolarized to fixed-polarization light with topology optimized metasurfaces

TL;DR

This paper presents topology-optimized metasurfaces capable of nearly 100% efficient conversion of unpolarized light into a single polarization, surpassing traditional 50% efficiency limits and enabling flexible polarization splitting.

Contribution

The authors demonstrate a novel metasurface design that achieves near-complete unpolarized-to-polarized light conversion and arbitrary power splitting among multiple outputs.

Findings

Achieved extinction ratio approaching 100 in laboratory measurements.

Demonstrated flexible power splitting among three or more polarized outputs.

Surpassed the fundamental 50% efficiency limit of conventional polarizers.

Abstract

Conventional polarizers and polarization beam splitters have a fundamental limit of 50\% efficiency when converting unpolarized light into one specific polarization. Here, we overcome this restriction and achieve near-complete conversion of unpolarized light to a single pure polarization state at several outputs of topology-optimized metasurfaces. Our fabricated metasurface achieves an extinction ratio approaching 100, when characterized with laboratory measurements. We further demonstrate that arbitrary power splitting can be achieved between three or more polarized outputs, offering flexibility in target illumination. Our results provide a path toward greatly improving the efficiency of common unpolarized light sources in a variety of applications requiring pure polarizations.