Light shift produced by the AC Stark effect is one of the major factors limiting the accuracy and long-term stability of a cold atom interferometer. The first order light shift can be canceled by fixing the power ratio of the Raman beams at a specified value. We report here a new method to stabilize the power ratio of the two Raman lasers with ∼100 kHz locking bandwidth, suppressing the effect of the first order light shift. We first mixed the two Raman lasers (at different optical frequencies) with a reference beam and then used two Schottky diode detectors to extract the corresponding beat note signals for each beam, which are much easier to be manipulated and processed as they are in the microwave band. The stability of the power ratio is improved by three orders of magnitude from 5.84 × 10-3 to 3.51 × 10-6 at 1 s averaging time and reaches 1.59 × 10-7 at 10 000 s integrating time when the servo loop is engaged. This method can be used in other precise quantum measurement based on the stimulated Raman transition and can be applied to compact inertial sensors.

中文翻译：

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冷原子干涉仪两束拉曼光束功率比高带宽伺服控制新方法

AC Stark 效应产生的光移是限制冷原子干涉仪精度和长期稳定性的主要因素之一。通过将拉曼光束的功率比固定在指定值，可以消除一阶光移。我们在此报告了一种新方法来稳定两个具有 ~100 kHz 锁定带宽的拉曼激光器的功率比，抑制一阶光移的影响。我们首先将两个拉曼激光器（在不同的光学频率下）与参考光束混合，然后使用两个肖特基二极管检测器为每个光束提取相应的拍音信号，这些信号在微波中更容易操作和处理乐队。功率比的稳定性提高了三个数量级，从 5.84 × 10-3 到 3.51 × 10-6 在 1 s 平均时间达到 1。59 × 10-7 在 10 000 s 积分时间，当伺服回路接合时。该方法可用于其他基于受激拉曼跃迁的精确量子测量，并可应用于紧凑型惯性传感器。