Tunable phononic coupling in excitonic quantum emitters

TL;DR

This paper demonstrates the creation of quantum emitters in WSe2 with tunable exciton-phonon coupling, enabling control over phonon-assisted single-photon emission for quantum information applications.

Contribution

It introduces a new solid-state quantum system with electrically tunable exciton-phonon interactions in strain-induced quantum dots.

Findings

Achieved >83% single-photon purity.

Observed multiple phonon replicas indicating phonon Fock states.

Demonstrated electrical tunability of phonon-photon coupling.

Abstract

Engineering the coupling between fundamental quantum excitations is at the heart of quantum science and technologies. A significant case is the creation of quantum light sources in which coupling between single photons and phonons can be controlled and harnessed to enable quantum information transduction. Here, we report the deterministic creation of quantum emitters featuring highly tunable coupling between excitons and phonons. The quantum emitters are formed in strain-induced quantum dots created in homobilayer semiconductor WSe2. The colocalization of quantum confined interlayer excitons and THz interlayer breathing mode phonons, which directly modulate the exciton energy, leads to a uniquely strong phonon coupling to single-photon emission. The single-photon spectrum of interlayer exciton emission features a single-photon purity >83% and multiple phonon replicas, each heralding the creation of a phonon Fock state in the quantum emitter. Owing to the vertical dipole moment of the interlayer exciton, the phonon-photon interaction is electrically tunable in a wide range, promising to reach the strong coupling regime. Our result demonstrates a new type of solid-state quantum excitonic-optomechanical system at the atomic interface that emits flying photonic qubits coupled with stationary phonons, which could be exploited for quantum transduction and interconnection.