Single photon emitters with polarization and orbital angular momentum locking in monolayer semiconductors

TL;DR

This paper proposes a method to generate polarization and orbital angular momentum locked and entangled single photons using excitons in monolayer semiconductors, tunable by strain and magnetic fields, for quantum information applications.

Contribution

It introduces a novel scheme to produce tunable polarization-OAM locked and entangled photons from excitons in monolayer semiconductors, leveraging valley-orbit coupling and external controls.

Findings

Excitons in monolayer TMDs exhibit valley-OAM entanglement when confined.

Exciton OAM can be transferred to emitted photons, creating polarization-OAM locked photons.

The proposed system allows high tunability and integration for quantum photonic devices.

Abstract

Excitons in monolayer transition metal dichalcogenide are endowed with intrinsic valley-orbit coupling between their center-of-mass motion and valley pseudospin. When trapped in a confinement potential, e.g., generated by strain field, we find that intralayer excitons are valley and orbital angular momentum (OAM) entangled. By tuning trap profile and external magnetic field, one can engineer the exciton states at ground state, and realize a series of valley-OAM entangled states. We further show that the OAM of excitons can be transferred to emitted photons, and these novel exciton states can naturally serve as polarization-OAM locked single photon emitters, which under certain circumstance become polarization-OAM entangled, highly tunable by strain trap and magnetic field. Our proposal demonstrates a novel scheme to generate polarization-OAM locked/entangled photons at nanoscale with high degree of integrability and tunability, pointing to exciting opportunities for quantum information applications.