Abstract
Homodyne detection is often used for interferometers based on nonlinear optical gain media. For the configuration of a seeded, "truncated SU(1,1)" interferometer Anderson, et al. [ Phys. Rev. A95, 063843 (2017)] showed how to optimize the homodyne detection scheme and demonstrated theoretically that it can saturate the quantum Cramer-Rao bound for phase estimation. In this work we extend those results by taking into account loss in the truncated SU(1,1) interferometer and determining the optimized homodyne detection scheme for phase measurement. Further, we build a truncated SU(1,1) interferometer and experimentally demonstrate that this optimized scheme achieves a reduction in noise level, corresponding to an enhanced potential phase sensitivity, compared to a typical homodyne detection scheme for a two-mode squeezed state. In doing so, we also demonstrate an improvement in the degree to which we can beat the standard quantum limit with this device.
Highlights
Interferometers allow for extremely sensitive measurements of optical phase
We extend their analysis to account for the loss in the interferometer in the low gain regime, and we examine the improvement in phase sensitivity, both theoretically and experimentally, offered by these optimized measurements over the weighted joint quadrature measurement for a truncated SU(1,1) interferometer
The class of interferometers based on active media has become of interest in the pursuit of metrological devices that can beat the standard quantum limit
Summary
Interferometers allow for extremely sensitive measurements of optical phase. The optimum sensitivity of a specific interferometer is related to the optical quantum state that is used for sensing the phase and the placement of the phase object in the interferometer. Anderson et al [1] showed theoretically that by changing the relative weights of the signals from the two homodyne detectors (i.e., by changing λ in Fig. 1b), one can saturate the QCRB with any amount of correlations between the probe and conjugate, i.e., squeezing, which is set by the gain (G) of the 4WM process In this manuscript, we extend their analysis to account for the loss in the interferometer in the low gain regime, and we examine the improvement in phase sensitivity, both theoretically and experimentally, offered by these optimized measurements over the weighted joint quadrature measurement for a truncated SU(1,1) interferometer. We construct a truncated SU(1,1) interferometer and show that by using this modified, weighted joint homodyne detection scheme, one can reduce noise in the phase measurement and can achieve enhanced phase sensitivities compared to the weighted scheme
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
