Multifunctional meta-mirror: polarization splitting and focusing

TL;DR

This paper presents a metasurface device that can split orthogonal polarizations and focus light into different spots, with high efficiency and broadband operation, suitable for integration into photonic systems.

Contribution

The authors demonstrate a multifunctional gap surface plasmon metasurface capable of polarization splitting and focusing in reflection mode, with high efficiency and broadband near-infrared performance.

Findings

Achieved polarization splitting and focusing with up to 65% efficiency.

Demonstrated broadband operation in the 750-950 nm range.

Device exhibits high polarization extinction ratio (~30 dB).

Abstract

Metasurfaces are paving the way to improve traditional optical components by integrating multiple functionalities into one optically flat metasurface design. We demonstrate the implementation of a multifunctional gap surface plasmon-based metasurface which, in reflection mode, splits orthogonal linear light polarizations and focuses into different focal spots. The fabricated configuration consists of 50 nm thick gold nanobricks with different lateral dimensions, organized in an array of 240 nm x 240 nm unit cells on the top of a 50 nm thick silicon dioxide layer, which is deposited on an optically thick reflecting gold substrate. Our device features high efficiency (up to ~65%) and polarization extinction ratio (up to ~30 dB), exhibiting broadband response in the near-infrared band (750-950 nm wavelength) with the focal length dependent on the wavelength of incident light. The proposed optical component can be forthrightly integrated into photonic circuits or fiber optic devices.