平行线偏振光CPT原子频标研究

In certain B fields, lineally polarized light （lin//lin） is equivalent to the composition of two superimposed left and right circularly polarized lights. A bi-chromatic lin//lin laser beam interacts with atom ensemble can form several CPT state preparation structures, and in this project we will utilize two λ type CPT state preparation structures to prepare CPT states. With the realized resonance signal as microwave discrimination signal, we will realize the lin//lin scheme CPT atomic clock. Because the spin polarized dark state atoms are eliminated in lin//lin scheme, considerable more atoms will contribute to CPT resonance signal than the conventional CPT atomic clock scheme, and the clock with better frequency stability is expected. In this project we will study the lin//lin scheme related physics and techniques, realize the principle prototype of the lin//lin scheme CPT atomic clock, and evaluate its characteristics and application ranges.

线偏振光在特定磁场中等效左、右旋圆偏振光的叠加，双色平行线偏振光（lin//lin）与原子作用可以实现多个CPT态制备结构，本项目将研究利用其中两个∧结构产生的CPT共振信号作为微波鉴频信号实现原子频标。lin//lin方案消除了极化暗态，使参与制备CPT态的原子数量大幅度高于目前普遍应用的圆偏振光CPT原子频标方案,可望获得频率稳定度更高的CPT原子频标。本项目将全面研究lin//lin方案所涉及的物理和技术问题，研制出闭环锁定的lin//lin CPT原子频标实验室原理样机，并评估该方案原子频标的特性和适用范围。

流行CPT原子钟因采用圆偏振多色激光，圆偏振光减少了工作原子数量，多色光的无用光频成分只贡献只贡献本底噪声，这两原因使得频率稳定度较差。本项目旨在利用线偏振(lin//lin)光增加工作原子数量，通过执行项目我们发展了一种新型lin//lin CPT原子钟方案，利用Faraday效应和差分探测技术不仅增加工作原子数量，而且有效消除无用光频本底噪声，研究结果表明该方案可以将频率稳定度改善一个量级。通过执行本项目我们已申请（受理并已公示）了专利1项，在Opt. Lett. 等期刊发表论文6篇，另已完成两篇论文将在近期发表，项目任务书中“预期成果”的目标已经全部实现。采用所发展的方案可望实现高性能的芯片原子钟。