标题： 剪切非线性磁光旋转：一种精密测量技术 显示英文标题

标题： Chopped nonlinear magneto-optic rotation: a technique for precision measurements

摘要： 我们开发了一种使用非线性磁光旋转（NMOR）精确测量小磁场的技术。 该技术依赖于共振激光束被斩波。 在开启时间，原子被光学泵浦到对齐的基态（$\Delta m=2$共振）。 在关闭时间，它们以拉莫尔频率围绕磁场自由进动。 如果开启-关闭调制频率与拉莫尔进动频率匹配（两倍），则每次循环中的旋转都会被共振增强，从而使得该过程类似于对拉莫尔频率的重复拉姆西测量。 我们在涂有石蜡的铯蒸气室中研究了斩波-NMOR。 反相解调的旋转显示出一个线宽为85$\mu$G的洛伦兹峰，对应于0.15 nG/$\sqrt{{\rm Hz}}$的灵敏度。 我们讨论了该技术在测量原子电偶极矩方面的潜力。 显示英文摘要

摘要： We have developed a technique for precise measurement of small magnetic fields using nonlinear magneto-optic rotation (NMOR). The technique relies on the resonant laser beam being chopped. During the on time, the atoms are optically pumped into an aligned ground state ($\Delta m=2$ coherence). During the off time, they freely precess around the magnetic field at the Larmor frequency. If the on-off modulation frequency matches (twice) the Larmor precession frequency, the rotation is resonantly enhanced in every cycle, thereby making the process like a repeated Ramsey measurement of the Larmor frequency. We study chopped-NMOR in a paraffin-coated Cs vapor cell. The out-of-phase demodulated rotation shows a Lorentzian peak of linewidth 85 $\mu$G, corresponding to a sensitivity of 0.15 nG/$\sqrt{{\rm Hz}}$. We discuss the potential of this technique for the measurement of an atomic electric-dipole moment.