An ultra-high gain single-photon transistor in the microwave regime

TL;DR

This paper demonstrates a microwave single-photon transistor with high gain and extinction ratio using circuit quantum electrodynamics, advancing quantum photonics and information processing capabilities.

Contribution

It introduces a novel microwave photonic transistor with record gain and extinction ratio, utilizing superconducting qubits and cavity coupling for single-photon level control.

Findings

Achieved a gain of up to 53.4 dB

Extinction ratio better than 20 dB

Outperforms previous optical devices by orders of magnitude

Abstract

A photonic transistor that can switch or amplify an optical signal with a single gate photon requires strong non-linear interaction at the single-photon level. Circuit quantum electrodynamics provides great flexibility to generate such an interaction, and thus could serve as an effective platform to realize a high-performance single-photon transistor. Here we demonstrate such a photonic transistor in the microwave regime. Our device consists of two microwave cavities dispersively coupled to a superconducting qubit. A single gate photon imprints a phase shift on the qubit state through one cavity, and further shifts the resonance frequency of the other cavity. In this way, we realize a gain of the transistor up to 53.4 dB, with an extinction ratio better than 20 dB. Our device outperforms previous devices in the optical regime by several orders in terms of optical gain, which indicates a great potential for application in the field of microwave quantum photonics and quantum information processing.