Optically heralded microwave photon addition

• Published in: Nature physics Vol. 19; no. 10; pp. 1423 - 1428
• Main Authors: Jiang, Wentao, Mayor, Felix M., Malik, Sultan, Van Laer, Raphaël, McKenna, Timothy P., Patel, Rishi N., Witmer, Jeremy D., Safavi-Naeini, Amir H.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.10.2023; Nature Publishing Group; Nature Publishing Group (NPG)
• Subjects: 639/766/483/3925; 639/766/483/481; Atomic; Circuits; Classical and Continuum Physics; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Complex Systems; Condensed Matter Physics; Efficiency; Light; Mathematical and Computational Physics; Molecular; Nanowires; Noise generation; Optical and Plasma Physics; Photons; Physics; Physics and Astronomy; Piezoelectricity; Quantum entanglement; quantum information; Quantum phenomena; Qubits (quantum computing); Semiconductors; Silicon; single photons and quantum effects; Theoretical; Thermal noise; Transducers
• ISSN: 1745-2473; 1745-2481; 1745-2481
• DOI: 10.1038/s41567-023-02129-w

Photons with optical frequencies of a few hundred terahertz are perhaps the only way to distribute quantum information over long distances. Superconducting qubits, which are one of the most promising approaches for realizing large-scale quantum machines, operate on microwave photons at frequencies that are ~40,000 times lower. To network these quantum machines across appreciable distances, we must bridge this frequency gap. Here we implement and demonstrate a transducer that can generate correlated optical and microwave photons. We use it to show that by detecting an optical photon we generate an added microwave photon with an efficiency of ~35%. Our device uses a gigahertz nanomechanical resonance as an intermediary, which efficiently couples to optical and microwave channels through strong optomechanical and piezoelectric interactions. We show continuous operation of the transducer with 5% frequency conversion efficiency, input-referred added noise of ~100, and pulsed microwave photon generation at a heralding rate of 15 Hz. Optical absorption in the device generates thermal noise of less than two microwave photons. Improvements of the system efficiencies and device performance are necessary to realize a high rate of entanglement generation between distant microwave-frequency quantum nodes, but these enhancements are within reach. Many quantum devices operate in the microwave regime, but long-distance communication relies on optical photons. A nanomechanical resonator can be used to create entangled optical and microwave photons linking the two frequency regimes.