Observation of Resonant Photon Blockade at Microwave Frequencies Using Correlation Function Measurements

TLDR

Creating a train of single photons and monitoring its propagation and interaction is challenging in most physical systems, as photons generally interact very weakly with other systems. The study observes photon blockade via second‑order correlation function measurements. Microwave photons are confined in a transmission‑line resonator with embedded qubits to mediate photon‑photon interactions, and the setup is used to study resonance fluorescence and Rayleigh scattering in Mollow‑triplet‑like spectra. The experiments demonstrate clear antibunching of continuously pumped single microwave photons using beam splitters, amplifiers, and quadrature detectors.

Abstract

Creating a train of single photons and monitoring its propagation and interaction is challenging in most physical systems, as photons generally interact very weakly with other systems. However, when confining microwave frequency photons in a transmission line resonator, effective photon-photon interactions can be mediated by qubits embedded in the resonator. Here, we observe the phenomenon of photon blockade through second-order correlation function measurements. The experiments clearly demonstrate antibunching in a continuously pumped source of single microwave photons measured using microwave beam splitters, linear amplifiers, and quadrature amplitude detectors. We also investigate resonance fluorescence and Rayleigh scattering in Mollow-triplet-like spectra.