Optomagnonic generation of entangled travelling fields with different polarizations

TL;DR

This paper demonstrates how optomagnonic interactions in a YIG sphere can be used to generate entangled optical fields with different polarizations, advancing quantum network components.

Contribution

It introduces a protocol for entangling propagating optical fields via magnon-induced Brillouin scattering in whispering gallery modes.

Findings

Entanglement between different polarization optical fields achieved.

Optimal conditions for strong entanglement identified.

Utilizes magnon-mediated Stokes and anti-Stokes scattering.

Abstract

The optomagnonic coupling between magnons and optical photons is an essential component for building remote quantum networks based on magnonics. Here we show that such a coupling, manifested as the magnon-induced Brillouin light scattering, can be exploited to entangle two propagating optical fields. The protocol employs two pairs of the whispering gallery modes coupled to the same magnon mode in a YIG sphere. In each pair a strong pump field is applied to activate either Stokes or anti-Stokes scattering. Due to the magnon mode involving in the two scattering processes and as a mediation, Stokes and anti-Stokes photons of different polarizations get entangled. The entanglement can be extracted by filtering the travelling output fields centered at the Stokes and anti-Stokes sidebands. Optimal conditions are identified under which strong output entanglement can be achieved.