Abstract
Abstract
Quantum squeezing, which makes measurement sensitivity beyond classical limit by reducing system noise, is an essential non-classical resource for quantum metrology. It is of great importance to enhance quantum squeezing since the squeezing degree directly determines the extent to which measurement sensitivity beats the classical limit. Recently, a two-mode phase-sensitive amplifier has been utilized to enhance the quantum squeezing of phase-insensitive amplifier. However, such enhancement has an intrinsic limit of 3 dB. Here we show that such limit of 3 dB can be overcome by utilizing multi-beam interference. Specifically, a quantum squeezing enhancement of about 3.67 dB is observed by direct measurement. Moreover, we find that the amount of quantum squeezing enhancement increases as the number of multi-beam interference increases, which clearly shows that beating the quantum squeezing enhancement limit of 3 dB is induced by multi-beam interference. Our results here provide an efficient way to enhance the quantum squeezing.
Funder
Natural Science Foundation of Chongqing Municipality
Shanghai Sailing Program
Innovation Program of Shanghai Municipal Education Commission
National Natural Science Foundation of China
Basic Research Project of Shanghai Science and Technology Commission
Program of Shanghai Academic Research Leader
111 project
Shanghai Municipal Science and Technology Major Project
Minhang Leading Talents
Natural Science Foundation of Shanghai Municipality
Subject
Electrical and Electronic Engineering,Physics and Astronomy (miscellaneous),Materials Science (miscellaneous),Atomic and Molecular Physics, and Optics