The phase sensitivity of an SU(1,1) interferometer with homodyne detection

TL;DR

This paper theoretically analyzes the phase sensitivity of an SU(1,1) interferometer with homodyne detection, showing it can surpass intensity detection and reach the Heisenberg limit under specific conditions.

Contribution

It demonstrates that homodyne detection improves phase sensitivity over intensity detection in an SU(1,1) interferometer with coherent and squeezed vacuum inputs, identifying optimal parameter ranges.

Findings

Homodyne detection outperforms intensity detection in phase sensitivity.

Maximum sensitivity is achieved at moderate squeezing levels.

Heisenberg limit can be approached with current experimental capabilities.

Abstract

We theoretically study the phase sensitivity of the SU(1,1) interferometer with a coherent light together with a squeezed vacuum input case using the method of homodyne. We find that the homodyne detection has better sensitivity than the intensity detection under this input case. For a certain intensity of coherent light (squeezed light) input, the relative phase sensitivity is not always better with increasing the squeezed strength (coherent light strength). The phase sensitivity can reach the Heisenberg limit only under a certain moderate parameter interval, which can be realized with current experiment ability.