Half-wave plate based on a birefringent metamaterial in the visible range

TL;DR

This paper presents a numerically designed birefringent metamaterial-based half-wave plate operating in the visible spectrum, achieving over 60% transmission and significant birefringence at 737 nm for integrated photonics applications.

Contribution

The paper introduces a novel design of a birefringent metamaterial half-wave plate with optimized efficiency and high birefringence in the visible range, using a simple rectangular aperture array.

Findings

Transmission coefficient exceeds 60% at 737 nm

Achieves birefringence of 2.1

Operates effectively in the visible spectrum

Abstract

In the present paper, a half-wave plate (HWP) based on a birefringent metamaterial is numerically designed to operate in the visible range. The proposed structure consists of an array of double-pattern perpendicular rectangular aperture (RAA) engraved into opaque silver film deposited on a glass substrate. One of the apertures is glass filled. The operating principle of this plate is based on the excitation and the propagation of one guided mode inside each aperture but with different effective index. At the output side, a phase difference is obtained whose value mainly depends on the metal thickness. We have investigated the most simplest configurations using a homemade code based on the finite difference time domain method to design a half-plate with optimized efficiency resulting in transmission coefficient of more than $60\%$ together with a birefringence of $2.1$ at an operation wavelength of 737 nm. This kind of anisotropic metasurface promises a wide range of applications in integrated photonics.