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arXiv · 1711.06226

Phase sensitivity of gain-unbalanced nonlinear interferometers

E. Giese·S. Lemieux·M. Manceau·R. Fickler·R. W. Boyd
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Abstract

The phase uncertainty of an unseeded nonlinear interferometer, where the output of one nonlinear crystal is transmitted to the input of a second crystal that analyzes it, is commonly said to be below the shot-noise level but highly dependent on detection and internal loss. Unbalancing the gains of the first (source) and second (analyzer) crystals leads to a configuration that is tolerant against detection loss. However, in terms of sensitivity, there is no advantage in choosing a stronger analyzer over a stronger source, and hence the comparison to a shot-noise level is not straightforward. Internal loss breaks this symmetry and shows that it is crucial whether the source or analyzer is dominating. Based on these results, claiming a Heisenberg scaling of the sensitivity is more subtle than in a balanced setup.

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E. Giese, S. Lemieux, M. Manceau, R. Fickler, R. W. Boyd. 2017-11-16. Phase sensitivity of gain-unbalanced nonlinear interferometers. https://doi.org/10.1103/physreva.96.053863

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