Broadband wide-view all-dielectric handedness-preserving mirror

TL;DR

This paper presents the design and experimental validation of a broadband all-dielectric mirror that preserves light's handedness in the near-infrared, with high reflection efficiency and robustness to incident angle variations.

Contribution

It introduces a novel all-dielectric, wideband mirror with handedness preservation, optimized via genetic algorithms and demonstrated experimentally with high performance.

Findings

Over 100 nm reflection band with >98% handedness preservation

Total reflection coefficient of 80% achieved

Maintains high performance under oblique incidence up to ±15°

Abstract

We report the theoretical design and experimental realization of a wideband, all-dielectric mirror that preserves the handedness of incident light upon reflection in the near-infrared range. The mirror consists of a high-contrast, near-subwavelength, one-dimensional dielectric grating on a Bragg mirror. We optimized this structure using a genetic algorithm and demonstrated its robustness against geometric imperfections and oblique incidence. Experimental reflection spectra measured under normal incidence in a circular polarization basis demonstrate a more than 100-nm-wide reflection band in which more than 98% of the reflected light preserves its handedness. The total reflection coefficient reached 80%. Furthermore, we demonstrate that the fabricated mirror maintains high performance even under oblique incidence for angles up to $\pm 15^\circ$. Owing to these unique characteristics, this mirror can serve as a reflective phase plate, making it an excellent candidate for the creation of a Fabry-P\'erot resonator for chiral light.