A single-photon switch and transistor enabled by a solid-state quantum memory

TL;DR

This paper demonstrates a solid-state quantum memory-based single-photon switch and transistor using a semiconductor spin qubit coupled to a nanophotonic cavity, enabling fast and strong photon-photon interactions for quantum information processing.

Contribution

It introduces a novel solid-state device that achieves deterministic control of light at the single-photon level using a semiconductor quantum memory.

Findings

Switching of a signal field with up to 27.7 photons

Switching time of 63 picoseconds

Strong photon-photon interactions achieved

Abstract

Single-photon switches and transistors generate strong photon-photon interactions that are essential for quantum circuits and networks. However, to deterministically control an optical signal with a single photon requires strong interactions with a quantum memory, which have been lacking in a solid-state platform. We realize a single-photon switch and transistor enabled by a solid-state quantum memory. Our device consists of a semiconductor spin qubit strongly coupled to a nanophotonic cavity. The spin qubit enables a single gate photon to switch a signal field containing up to an average of 27.7 photons, with a switching time of 63 ps. Our results show that semiconductor nanophotonic devices can produce strong and controlled photon-photon interactions that could enable high-bandwidth photonic quantum information processing.