Resolution improvement of angular rotation measurement through even coherent states coupled with parity detection strategy
Lili Hao, Hongxia Tang, Qiang Wang · Journal of Optics · 2020
Abstract Coherent superposition and squeezing are the main characteristics of even coherent states, which indicates even coherent states possessing extensive application prospect. In this paper, we propose a quantum strategy which exploits even coherent states with nonzero orbital angular momentum as the input and parity detection for signal processing method in angular rotation measurement. In this manner, the signal peak of the proposed strategy is narrower than that of the existing intensity detection method and gives 100% visibility relative to the projection measurement scheme. More importantly, the proposed scheme obtains 2-fold resolution improvement compared with that of coherent states strategy. Additionally, the effect of the phase instability is investigated and then the physical essence of that resolution improvement is detailed.