A bright triggered twin-photon source in the solid state

TL;DR

This paper demonstrates an efficient, triggered solid-state source of twin photons using a semiconductor quantum dot, achieving high emission rates and photon indistinguishability, with potential applications in quantum optics and biology.

Contribution

It introduces a novel triggered twin-photon source based on a quantum dot, surpassing previous methods in emission rate and integration efficiency.

Findings

Emission rate of up to 234 kHz for photon pairs

High photon-indistinguishability verified

Direct observation and reconstruction of twin-photon emission

Abstract

A non-classical light source emitting pairs of identical photons represents a versatile resource of interdisciplinary importance with applications in quantum optics and quantum biology. Emerging research fields, which benefit from such type of quantum light source, include quantum-optical spectroscopy or experiments on photoreceptor cells sensitive to photon statistics. To date, photon twins have mostly been generated using parametric downconversion sources, relying on Poissonian number distributions, or atoms, exhibiting low emission rates. Here, we propose and experimentally demonstrate the efficient, triggered generation of photon twins using the energy-degenerate biexciton-exciton radiative cascade of a single semiconductor quantum dot. Deterministically integrated within a microlens, this nanostructure emits highly-correlated photon pairs, degenerate in energy and polarization, at a rate of up to (234 $\pm$ 4) kHz. Furthermore, we verify a significant degree of photon-indistinguishability and directly observe twin-photon emission by employing photon-number-resolving detectors, which enables the reconstruction of the emitted photon number distribution.