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arXiv · 1704.04261

Optimal phase measurements with bright and vacuum-seeded SU(1,1) interferometers

B. E. Anderson·B. L. Schmittberger·P. Gupta·K. M. Jones·P. D. Lett
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Abstract

The SU(1,1) interferometer can be thought of as a Mach-Zehnder interferometer with its linear beamsplitters replaced with parametric nonlinear optical processes. We consider the cases of bright and vacuum-seeded SU(1,1) interferometers using intensity or homodyne detectors. A simplified, truncated scheme with only one nonlinear interaction is introduced, which not only beats conventional intensity detection with a bright seed, but can saturate the phase sensitivity bound set by the quantum Fisher information. We also show that the truncated scheme achieves a sub-shot-noise phase sensitivity in the vacuum-seeded case, despite the phase-sensing optical beams having no well-defined phase.

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B. E. Anderson, B. L. Schmittberger, P. Gupta, K. M. Jones, P. D. Lett. 2017-04-13. Optimal phase measurements with bright and vacuum-seeded SU(1,1) interferometers. https://doi.org/10.1103/physreva.95.063843

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