Eur. Phys. J. Plus (2021) 136: 878
https://doi.org/10.1140/epjp/s13360-021-01883-1

Regular Article

High-precision measurement of tiny Doppler frequency shifts based on quantum weak measurement with energy recycling

Department of Physics, Harbin Institute of Technology, 150001, Harbin, China

^b zhangzijing@hit.edu.cn

Received: 28 January 2021
Accepted: 18 August 2021
Published online: 26 August 2021

Abstract

It is of great significance to measure tiny Doppler frequency shifts precisely, for its importance in velocity measurement. However, the precision of classical measurement schemes for tiny Doppler frequency shifts is restricted by the shot noise limit. The emergence of quantum weak measurement can significantly reduce technical noise compared with classical measurements. Here, a scheme to realize tiny Doppler measurement by using quantum weak measurement technology is proposed. This scheme realizes the coupling of the polarization state and the transversal position state of a beam and then post-selects the polarization state. Finally, the tiny Doppler frequency shifts are amplified. At the same time, the energy recycling technology is incorporated to increase the best measurement precision by 1000 times compared with the classical measurements. Considering the loss in the energy recycling cavity, we draw the following conclusion: When the loss rate in the cavity does not exceed 20%, the precision of our scheme can be twice of the shot noise limit of the classical measurement.