Realizing spin-dependent gauge field with biaxial metamaterials

TL;DR

This paper demonstrates a practical method to realize spin-dependent gauge fields in the long wavelength regime using biaxial metamaterials, enabling control of light pseudospins and advancing topological photonics applications.

Contribution

It introduces a novel design and fabrication of a biaxial metamaterial with split dispersion surface to realize spin-dependent gauge fields in real space.

Findings

Experimental visualization of magnetic force bending of light pseudospins

Demonstration of optical spin Hall effect in a biaxial metamaterial

Potential for developing pseudospin-based optical devices

Abstract

Artificial magnetic field in electromagnetism is becoming an emerging way as a robust control of light based on its geometric and topological nature. Other than demonstrating topological photonics properties in the diffractive regime using photonic crystals or arrays of waveguides, it will be of great interest if similar manipulations can be done simply in the long wavelength limit, in which only a few optical parameters can be used to describe the system, making the future optical component design much easier. Here, by designing and fabricating a metamaterial with split dispersion surface, we provide a straight-forward experimental realization of spin-dependent gauge field in the real space using a biaxial material. A "magnetic force bending" for light of desired pseudospins is visualized experimentally by such a gauge field as a manifestation of optical spin Hall effect. Such a demonstration is potentially useful to develop pseudospin optics, topological components and spin-enabled transformation optical devices.