Super-resolving phase measurement with short wavelength NOON states by quantum frequency up-conversion

TL;DR

This paper demonstrates super-resolving phase measurement using short wavelength NOON states generated via quantum frequency up-conversion, surpassing the standard quantum limit for high-precision quantum metrology.

Contribution

The authors experimentally realize a short wavelength two-photon entangled state through quantum frequency up-conversion, enabling enhanced optical phase measurement beyond classical limits.

Findings

Achieved nearly perfect Hong-Ou-Mandel interference after up-conversion.

Demonstrated phase measurement surpassing the standard quantum limit.

Produced high-visibility entangled states at short wavelengths.

Abstract

Precise measurements are the key to advances in all fields of science. Quantum entanglement shows higher sensitivity than achievable by classical methods. Most physical quantities including position, displacement, distance, angle, and optical path length can be obtained by optical phase measurements. Reducing the photon wavelength of the interferometry can further enhance the optical path length sensitivity and imaging resolution. By quantum frequency up conversion, we realized a short wavelength two photon number entangled state. Nearly perfect Hong Ou Mandel interference is achieved after both 1547-nm photons are up converted to 525 nm. Optical phase measurement of two photon entanglement state yields a visibility greater than the threshold to surpass the standard quantum limit. These results offer new ways for high precision quantum metrology using short wavelength quantum entanglement number state.