基于相干极化调制的小型化CPT原子钟进展

Towards a Miniaturized CPT Atomic Clock based on Constructive Polarization Modulation

基于相干布局囚禁(Coherent Population Trapping)的被动型气泡原子钟,因其优良的短稳2E-13@1s和中期稳定度2.5E-15@10^4s,而成为高性能原子钟的有力竞争者。本文基于一种新构型来探索实现高性能小型化CPT原子钟。我们通过3.4GHz微波直接调制分布式布拉格反射(DBR)激光器产生相干双色光,同时在微波和激光光束上分别施加同步的相位调制和偏振调制,实现相干极化调制,获得了较高对比度(14.7%)和较窄线宽(416Hz)的CPT共振信号。该方案采用直接调制技术使原子钟系统体积、复杂性和环境敏感性都得到减小,这使得高性能CPT原子钟的小型化成为可能。

The passive vapor cell atomic clock based on the coherent population trapping(CPT)has become a competitive candidate for high performance atomic clocks for its excellent short-term stability(2E-13@1s)and mediumterm stability(2.5 E-15@10^4s).A high-performance miniaturized CPT atomic clock based on a new configuration is studied here.We compress the clock size by directly modulating a distributed Bragg reflector(DBR)laser with 3.4 GHz microwave.Moreover,the synchronous phase and polarization modulation are successfully applied to microwave and laser beams respectively,which form the so-called constructive polarization modulation.A CPT atomic clock signal with high contrast(14.7%)and narrow linewidth(416 Hz)is obtained.The size,complexity and environmental sensitivity of the clock system are significantly reduced due to the direct modulation,thus it leads to a feasible way to implement a compact and high-performance CPT atomic clock.