High precision interferometers are the building blocks of precision metrology and the ultimate interferometric sensitivity is limited by the quantum noise. Here we propose and experimentally demonstrate a compact quantum interferometer involving two optical parametric amplifiers and the squeezed states generated within the interferometer are directly used for the phase-sensing quantum state. By both squeezing shot noise and amplifying phase-sensing intensity the sensitivity improvement of 4.86±0.24 dB beyond the standard quantum limit is deterministically realized and a minimum detectable phase smaller than that of all present interferometers under the same phase-sensing intensity is achieved. This interferometric system has significantly potential applications in a variety of measurements for tiny variances of physical quantities.
@article{arxiv.2005.01911,
title = {Quantum interferometer combining squeezing and parametric amplification},
author = {Xiaojie Zuo and Zhihui Yan and Yanni Feng and Jingxu Ma and Xiaojun Jia and Changde Xie and Kunchi Peng},
journal= {arXiv preprint arXiv:2005.01911},
year = {2020}
}