Vertical routing of spinning dipoles radiation from a chiral metamembrane

TL;DR

This paper introduces a chiral bi-metasurface membrane that acts as a perfect photonic router, directing spin-polarized light either upwards or downwards with 100% efficiency due to Fano-resonance effects.

Contribution

It demonstrates a novel chiral bi-metasurface design enabling spin-dependent directional light emission with high efficiency, advancing photonic routing technology.

Findings

Chiral bi-metasurface achieves spin-dependent directional emission.

Fano-resonance explains the routing mechanism.

100% routing efficiency demonstrated.

Abstract

We propose a perfect photonic router based on a specially designed chiral bi-metasurface membrane for spin-polarized point light sources. Due to the mirror symmetry breaking in the chiral metamembrane, the radiation power flux of the clockwise and counterclockwise spinning dipoles to the opposite sides of the slab becomes different. We show that spinning dipoles in the specially designed chiral D$_4$-symmetrical bi-metasurface membrane can emit light either upwards or downwards depending on their rotation direction. We attribute this phenomenon to the Fano-resonance effect which is a result of the guided modes coupling with the far field. We show the advantage of D$_4$-symmetrical structures for the achievement of 100\% routing efficiency. This phenomenon can find applications in spintronics for spin-selective inter-chip coupling or as a measurement tool of spin polarization in memory cells.