Pickston Alexander, Graffitti Francesco, Barrow Peter, Morrison Christopher L, Ho Joseph, Brańczyk Agata M, Fedrizzi Alessandro
Opt Express. 2021 Mar 1;29(5):6991-7002. doi: 10.1364/OE.416843.
The ideal photon-pair source for building up multi-qubit states needs to produce indistinguishable photons with high efficiency. Indistinguishability is crucial for minimising errors in two-photon interference, central to building larger states, while high heralding rates will be needed to overcome unfavourable loss scaling. Domain engineering in parametric down-conversion sources negates the need for lossy spectral filtering allowing one to satisfy these conditions inherently within the source design. Here, we present a telecom-wavelength parametric down-conversion photon source that operates on the achievable limit of domain engineering. We generate photons from independent sources which achieve two-photon interference visibilities of up to 98.6 ± 1.1% without narrow-band filtering. As a consequence, we reach net heralding efficiencies of up to 67.5%, which corresponds to collection efficiencies exceeding 90%.
用于构建多量子比特态的理想光子对源需要高效地产生不可区分的光子。不可区分性对于最小化双光子干涉中的误差至关重要，而双光子干涉是构建更大量子态的核心，同时需要高的预示率来克服不利的损耗缩放。参量下转换源中的畴工程消除了对有损光谱滤波的需求，从而能够在源设计中固有地满足这些条件。在此，我们展示了一种工作在畴工程可实现极限的电信波长参量下转换光子源。我们从独立源产生光子，这些光子在没有窄带滤波的情况下实现了高达98.6±1.1%的双光子干涉可见度。因此，我们实现了高达67.5%的净预示效率，这对应于超过90%的收集效率。
