Vertical Routing of Spinning-Dipole Radiation from a Chiral Metasurface

We propose a perfect photonic router based on a specially designed chiral bimetasurface 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 D₄-symmetrical bimetasurface membrane can emit light either upward or downward 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 D₄-symmetrical structures for the achievement of 100% routing efficiency. This phenomenon can find applications in spintronics for spin-selective interchip coupling or as a measurement tool of spin polarization in memory cells.