Observation of intensity squeezing in resonance fluorescence from a solid-state device

TL;DR

This paper reports the first observation of intensity squeezing in resonance fluorescence from a solid-state quantum dot system, demonstrating subshot-noise photon fluctuations suitable for quantum metrology.

Contribution

It presents the experimental demonstration of intensity squeezing in resonance fluorescence from a solid-state device, overcoming previous inefficiencies and providing a new standard for quantum optical measurements.

Findings

Observed 0.59 dB intensity squeezing in resonance fluorescence

Achieved 22.6% system efficiency in photon detection

Estimated corrected squeezing of 3.29 dB at the first lens

Abstract

Intensity squeezing, i.e., photon number fluctuations below the shot noise limit, is a fundamental aspect of quantum optics and has wide applications in quantum metrology. It was predicted in 1979 that the intensity squeezing could be observed in resonance fluorescence from a two-level quantum system. Yet, its experimental observation in solid states was hindered by inefficiencies in generating, collecting and detecting resonance fluorescence. Here, we report the intensity squeezing in a single-mode fibre-coupled resonance fluorescence single-photon source based on a quantum dot-micropillar system. We detect pulsed single-photon streams with 22.6% system efficiency, which show subshot-noise intensity fluctuation with an intensity squeezing of 0.59 dB. We estimate a corrected squeezing of 3.29 dB at the first lens. The observed intensity squeezing provides the last piece of the fundamental picture of resonance fluorescence; which can be used as a new standard for optical radiation and in scalable quantum metrology with indistinguishable single photons.