Long Jin-Bao, Yang Sheng-Jun, Chen Shuai, Pan Jian-Wei
Opt Express. 2018 Oct 15;26(21):27773-27786. doi: 10.1364/OE.26.027773.
Locking of a laser frequency to an atomic or molecular resonance line is a key technique in applications of laser spectroscopy and atomic metrology. Modulation transfer spectroscopy (MTS) provides an accurate and stable laser locking method which has been widely used. Normally, the frequency of the MTS signal would drift due to Zeeman shift of the atomic levels and rigorous shielding of stray magnetic field around the vapor cell is required for the accuracy and stability of laser locking. Here on the contrary, by applying a transverse bias magnetic field, we report for the first time observation of a magnetic-enhanced MTS signal on the transition of Rb D-line Fg = 1→ Fe = 0 (close to the repump transition of Fg = 1→ Fe = 2), with signal to noise ratio larger than 100:1. The error signal is immune to the external magnetic fluctuation. Compared to the ordinary MTS scheme, it provides a robust and accurate laser locking approach with more stable long-term performance. This technique can be conveniently applied in areas of laser frequency stabilization, laser manipulation of atoms and precision measurement.
将激光频率锁定到原子或分子共振线是激光光谱学和原子计量学应用中的一项关键技术。调制转移光谱（MTS）提供了一种准确且稳定的激光锁定方法，该方法已被广泛使用。通常，由于原子能级的塞曼位移，MTS信号的频率会发生漂移，为了保证激光锁定的精度和稳定性，需要对蒸汽池周围的杂散磁场进行严格屏蔽。相反，在这里，通过施加横向偏置磁场，我们首次报道了在Rb D线Fg = 1→Fe = 0跃迁（接近Fg = 1→Fe = 2的再泵浦跃迁）上观察到磁增强MTS信号，信噪比大于100:1。误差信号不受外部磁场波动的影响。与普通MTS方案相比，它提供了一种更稳定的长期性能的稳健且准确的激光锁定方法。该技术可方便地应用于激光频率稳定、原子的激光操控和精密测量等领域。
