冷原子干涉型重力仪中系统误差的快速获取

Rapid extraction of the systematic error in the cold-atom gravimeter

一般冷原子干涉仪是在固定拉曼脉冲时间间隔T的情况下,通过扫描拉曼激光的啁啾率获得原子干涉条纹。如果要绘制出相移随着T的变化,需要较长的测量时间。本文提出了用相位解调法快速提取冷原子干涉仪的相移的方法,通过此法,可以快速获得干涉仪在整个干涉区域的系统误差,并可以快速推断出在某些特定干涉时间内导致系统发生相位移动的潜在因素。进一步,我们在实验上通过这种相位解调法快速提取出了由于二阶塞曼效应引起的干涉仪的系统误差。实验结果与理论预测相吻合,并且与通过原子干涉条纹计算出来的相位移动一致。

Generally,the phase of the cold-atom interferometer is extracted from the atomic interference fringe,which can be obtained by scanning the chirp rate of the Raman lasers at a given interrogation time T. If the phase shift for each T is mapped with a series of measurements,the extraction time is limited by the protocol of each T measurement,and therefore increases dramatically when fine mapping is conducted with a small step of T. In this paper,the authors present a new method for rapid extraction of the phase shift via phase demodulation. By using this method,the systematic shifts can be mapped though the whole interference area. This method enables quick diagnostics of the potential cause of the phase shift in specific time. It is demonstrated experimentally that this method is effective for the evaluation of the systematic errors of the cold atomic gravimeter. The systematic phase error induced by the quadratic Zeeman effect in the free-falling region is extracted by this method. The measured results correspond well with the theoretic prediction and also agree with the results obtained by the fringe fitting method for each T.