Phase super-resolution with N00N states generated by on demand single-photon sources

TL;DR

This paper demonstrates phase super-resolution using N00N states generated by a quantum dot single-photon source, showing potential for scalable high-precision quantum measurements.

Contribution

It introduces a method to generate two-photon N00N states with a quantum dot source for super-resolving phase measurements, improving scalability over traditional sources.

Findings

Achieved phase super-resolution with quantum dot N00N states.

Observed interference fringes with doubled frequency.

Measured interference visibilities around 0.5.

Abstract

Multi-photon entangled states such as `N00N states' have attracted a lot of attention because of their possible application in high-precision phase measurements. So far, N00N states have been generated by spontaneous parametric down-conversion sources and by mixing quantum and classical light on a beam splitter. However, single-photon on demand sources promise to be more efficient and scalable than down-conversion sources which are probabilistic in nature. Here, we demonstrate super-resolving phase measurements based on two-photon N00N states generated by a quantum dot single-photon source utilizing the Hong-Ou-Mandel effect on a beam splitter. The quantum dot was excited through a two-photon resonant excitation scheme. Using a $\pi$-pulse, this results in the deterministic generation of indistinguishable single photons from both, the biexciton and exciton radiative recombination processes. Launching either type of the photons into both inputs of an interferometer, phase super-resolution, i.e. an interference fringe spacing with doubled rate relative to the single photon rate has been observed for both transitions. Interference visibilities of $V_{N=2,\mathit{XX}}=0.54\pm0.01$ for the biexciton and $V_{N=2,\mathit{X}}=0.46\pm0.02$ for the exciton transition have been obtained, respectively.