Spin-photon interface and spin-controlled photon switching in a nanobeam waveguide

TL;DR

This paper demonstrates an efficient, optically programmable spin-photon interface in a nanobeam waveguide, enabling deterministic spin preparation and a spin-controlled photon switch, advancing integrated quantum information processing.

Contribution

It introduces a novel integrated spin-photon interface with high fidelity and demonstrates a spin-controlled photon switch in a nanophotonic waveguide.

Findings

Spin can be prepared with 96% fidelity.

The system functions as a single-spin photonic switch.

Potential for on-chip quantum gates and photon transistors.

Abstract

Access to the electron spin is at the heart of many protocols for integrated and distributed quantum-information processing [1-4]. For instance, interfacing the spin-state of an electron and a photon can be utilized to perform quantum gates between photons [2,5] or to entangle remote spin states [6-9]. Ultimately, a quantum network of entangled spins constitutes a new paradigm in quantum optics [1]. Towards this goal, an integrated spin-photon interface would be a major leap forward. Here we demonstrate an efficient and optically programmable interface between the spin of an electron in a quantum dot and photons in a nanophotonic waveguide. The spin can be deterministically prepared with a fidelity of 96\%. Subsequently the system is used to implement a "single-spin photonic switch", where the spin state of the electron directs the flow of photons through the waveguide. The spin-photon interface may enable on-chip photon-photon gates [2], single-photon transistors [10], and efficient photonic cluster state generation [11].