Highly efficient heralding of entangled single photons
Sven Ramelow, Alexandra Mech, Marissa Giustina, Simon Gröblacher, Witlef Wieczorek, J. Beyer, Adriana E. Lita, Brice Calkins, Thomas Gerrits, Sae Woo Nam, Anton Zeilinger, Rupert Ursin · Optics Express · 2013
Single photons are an important prerequisite for a broad spectrum of quantum optical applications. We experimentally demonstrate a heralded single-photon source based on spontaneous parametric down-conversion in collinear bulk optics, and fiber-coupled bolometric transition-edge sensors. Without correcting for background, losses, or detection inefficiencies, we measure an overall heralding efficiency of 83%. By violating a Bell inequality, we confirm the single-photon character and high-quality entanglement of our heralded single photons which, in combination with the high heralding efficiency, are a necessary ingredient for advanced quantum communication protocols such as one-sided device-independent quantum key distribution.