近日，华中科技大学的胡忠坤&段小春及其研究团队取得一项新进展。经过不懈努力，他们成功评估啁啾拉曼激光器中频率依赖相位偏移对原子重力仪的影响。相关研究成果已于2024年12月19日在国际知名学术期刊《物理评论A》上发表。

在这项研究中，该研究团队研究了由于频率啁啾引起的拉曼激光器中的附加相位偏移。研究人员通过使用高速示波器记录拉曼激光器的拍频信号，直接测量了这一相位偏移，从而独立评估了该相位偏移对原子重力仪产生的误差。

同时，研究人员使用原子重力仪检测了附加相位偏移对重力测量的影响，结果与独立评估结果高度一致。值得注意的是，在进行差分测量时，通过反转拉曼激光器有效波矢的方向，仍可能存在微伽级别的残留误差。研究人员提出，原则上可以通过在差分测量中为两个方向选择相同的啁啾频率范围来消除这一残留误差。

据悉，光脉冲原子重力测量技术已成为精确测量绝对重力加速度的有力手段。在此技术中，通常使用拉曼激光来相干地操控原子波包，且其有效频率会被连续啁啾以补偿多普勒频移。

附：英文原文

Title: Evaluation of a frequency-dependent phase shift in chirped Raman lasers for atom gravimeters

Author: Yaoyao Xu¹, Qingsong Wang¹, Jiafeng Cui², Huaqing Luo¹, Qin Luo¹, Xiaobing Deng¹, Minkang Zhou¹, Xiaochun Duan^1,*, and Zhongkun Hu^1,†

Issue&Volume: 2024-12-19

Abstract: Light-pulse atom gravimetry has emerged as a powerful technique for precisely measuring absolute gravitational acceleration. Raman lasers are commonly used in this technique to coherently manipulate the atomic wave packet, of which the effective frequency is chirped continuously to compensate for the Doppler shift. In this study we investigate an additional phase shift in the Raman lasers that arises due to the frequency chirp. We directly measure this phase shift by recording the beat signal of the Raman lasers with a high-speed oscilloscope, providing an independent evaluation of the resultant error in atom gravimeters caused by this phase shift. Concurrently, we detect the influence of the additional phase shift on gravity measurements using our atom gravimeter, and the results are in good agreement with the independent evaluation. Notably, there may still be a residual error at the microgal level when performing differential measurements by reversing the direction of the effective wave vector of the Raman lasers. We propose that this residual error can in principle be eliminated by selecting the same chirp frequency range for both directions in the differential measurement.

DOI: 10.1103/PhysRevA.110.062816

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.062816