Publications associated with Ultrafast quantum optics and optical metrology

Quantum-enhanced interferometry with large heralded photon-number states


G Thekkadath, M Mycroft, B Bell, C Wade, A Eckstein, D Phillips, R Patel, A Buraczewski, A Lita, T Gerrits, S Nam, M Stobinska, A Lvovsky, I Walmsley

© 2020, The Author(s). Quantum phenomena such as entanglement can improve fundamental limits on the sensitivity of a measurement probe. In optical interferometry, a probe consisting of N entangled photons provides up to a N enhancement in phase sensitivity compared to a classical probe of the same energy. Here, we employ high-gain parametric down-conversion sources and photon-number-resolving detectors to perform interferometry with heralded quantum probes of sizes up to N = 8 (i.e. measuring up to 16-photon coincidences). Our probes are created by injecting heralded photon-number states into an interferometer, and in principle provide quantum-enhanced phase sensitivity even in the presence of significant optical loss. Our work paves the way toward quantum-enhanced interferometry using large entangled photonic states.

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