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 $π$ -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.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 $π$-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.

arXiv:1603.00906Mar 2, 20162 citations

Tera-mode of Spatiotemporal N00N States

Xiaoqin Gao, Yingwen Zhang, Alessio D’Errico +2 more

Two-photon interference is widely used in quantum information processing, e.g., state engineering and designing quantum gates, as well as in quantum sensing and metrology. This includes the generation and characterization of N00N states, which provide a phase measurement sensitivity that is beyond the shot-noise limit. There have been numerous efforts in generating N00N states with a photon number higher than 2, since their measurement sensitivity increases with N. Both photon number state and modal (temporal, spectral, and spatial) properties of light offer advantages in sensing, where the latter is achieved through mode-multiplexed measurements. Here, we experimentally demonstrate, with the aid of a recently developed photon-detection technology, measurement and characterization of up to tera-mode spatiotemporal correlations in two-photon interference and use it to generate high-dimensional two-photon N00N-states, which can be advantageous for multiphase estimation. We observe a high bi-photon interference and coalescence visibility of $\sim64\%$ and $\sim88\%$ for a tera ( $10^{12}$ ) and 0.2 tera ( $2\times 10^{11}$ ) spatiotemporal modes, respectively. These results open up a route for practical applications of using the spatiotemporal degrees of freedom in two-photon interference, and in particular, for quantum sensing and communication.Two-photon interference is widely used in quantum information processing, e.g., state engineering and designing quantum gates, as well as in quantum sensing and metrology. This includes the generation and characterization of N00N states, which provide a phase measurement sensitivity that is beyond the shot-noise limit. There have been numerous efforts in generating N00N states with a photon number higher than 2, since their measurement sensitivity increases with N. Both photon number state and modal (temporal, spectral, and spatial) properties of light offer advantages in sensing, where the latter is achieved through mode-multiplexed measurements. Here, we experimentally demonstrate, with the aid of a recently developed photon-detection technology, measurement and characterization of up to tera-mode spatiotemporal correlations in two-photon interference and use it to generate high-dimensional two-photon N00N-states, which can be advantageous for multiphase estimation. We observe a high bi-photon interference and coalescence visibility of $\sim64\%$ and $\sim88\%$ for a tera ($10^{12}$) and 0.2 tera ($2\times 10^{11}$) spatiotemporal modes, respectively. These results open up a route for practical applications of using the spatiotemporal degrees of freedom in two-photon interference, and in particular, for quantum sensing and communication.

Jul 6, 20210 citations

Interference with (Pseudo) Thermal Light

Km Nitu Rai, S. Basak, Subrata Sarangi +1 more

arXiv:2404.18606ResonanceFeb 3, 20250 citations

Interference of dissimilar photon sources

Anthony J. Bennett, Raj B. Patel, Christine A. Nicoll +2 more

arXiv:1006.0820Nature PhysicsAug 30, 200971 citations

π

-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.

\sim64\%

and

\sim88\%

for a tera (

10^{12}

) and 0.2 tera (

2\times 10^{11}

) spatiotemporal modes, respectively. These results open up a route for practical applications of using the spatiotemporal degrees of freedom in two-photon interference, and in particular, for quantum sensing and communication.