Phase Shift Of Double-Diffraction Raman Interference Due To High-Order Diffraction States

Double-diffraction Raman interference is a novel interference scheme developed in recent years. It has a potentially high measurement precision due to the symmetric interference loop with identical internal states. In this paper, we analyze the high-order diffraction process in double-diffraction Raman interference and derive state evolution equations that include multiple diffraction processes. The population evolution of the states and the Mach-Zehnder interference fringe are calculated under the action of a Raman laser. The thermal momentum distribution averaging and state grouping methods are employed to solve the problem of decoherence at different interference exit ports. We compare the phase shifts calculated by integrating the sensitivity function and the two-photon frequency shift and by numerically solving the state evolution equations with high-order diffraction states. The good agreement between the results of the two methods shows that the two-photon frequency shift is the main reason for the phase shift induced by the higher-order diffraction states. Finally, the test error of an equivalent principle test experiment due to this effect is analyzed. This paper may be helpful for the analysis and suppression of the systemic error in such experiments.