基于正交偏振探测技术的POP铷原子钟性能优化
文献类型：学位论文
| 作者 | 董功勋 |
| 文献子类 | 博士 |
| 导师 | 王育竹 |
| 关键词 | 脉冲光抽运铷原子钟 pulsed optically pumped Rubidium clock 正交偏振探测 orthogonal polarization detection technology 频率稳定度 frequency stability 原子相位反馈 atomic phase feedback |
| 其他题名 | Performance improvement on the POP Rubidium clock based on orthogonal polarization detection technology |
| 英文摘要 | 本文介绍了作者博士期间在基于正交偏振探测技术的脉冲光抽运（POP）铷原子钟平台上所进行的研究工作，包括POP原子钟性能优化以及新型POP原子钟技术探索。 为了改善POP原子钟性能，我们设计加工了一套新的小型化物理系统，其体积缩减到旧物理系统的1/4左右。我们 1)优化了微波腔内场型，通过微波光双共振信号验证了吸收泡体积内的微波磁场方向几乎都是沿着量子化轴方向，并在π/2的微波脉冲作用时得到对称的线宽压窄一半的Ramsey条纹。 2)充制了缓冲气体压力比合适的吸收泡，在59℃附近的频移温度系数约为2×10-11/℃；为了减少吸收泡的温度起伏，设计了新的温度控制电路，优化PID参数后，微波腔盖处的温度稳定度达到200μK@2,000 s。这两项改进降低了温度通过缓冲气体频移对频率稳定度的影响。 3)搭建了光功率稳定系统，在2000s时光功率稳定度达到4.7×10-4，相比于自由运转时提高了一个数量级，有效地降低了光功率抖动。 4)改进了电路。设计了新的恒流源电路，输出电流为0.5 mA时，相对电流稳定度在万秒进入3×10-6，有效降低了C场抖动；应用20位的数模转换器替换16位的数模转换器，使输出控制电压的分辨率由153μV提高到9μV，提高了输出控制电压的精度，有效地降低了电压噪声。 此外，还进行了参数优化，最终POP铷原子钟频率稳定度达到3.53×10-13@1s，并在2000s时达到4.91×10-15，这一指标已经很接近气泡原子钟频率稳定度世界记录保持者—意大利国家计量院的POP铷原子钟水平。在超过2000s后的中长期稳定度要稍微差一点，我们认为主要限制因素是温度起伏。 除了优化指标外，我们也开展了新型POP原子钟的技术探索。研究了使用大失谐光正交偏振探测对原子态进行无破坏探测；研究了微波相位调制技术；在此基础上实现了原子相位反馈，利用正相位反馈得到线宽压窄的Ramsey条纹，利用负相位反馈得到线性区不压窄的Ramsey条纹。这为后续进行原子相位锁定实验奠定了基础。; This thesis presents the research on the pulsed optically pumped Rubidium clock based on orthogonal polarization detection technology which includes the improvement of the POP atomic clock performance and exploration of new POP atomic clock technology. To improve the performance of the POP atomic clock，we developed a much more compact physics package with a total volume of about 1/4 of the precedent one. We 1） Optimized the field pattern of the microwave cavity. With the microwave-light double resonant signal, we verified that the new microwave cavity has a highly uniform magnetic field distribution oriented almost exclusively parallel to the quantization axis over the entire cell volume. And we got a symmetrical Ramsey fringe with a linewidth of only half of the normal one when the microwave pulse area is π/2. 2） Manufactured a Rubidium cell with a suitable pressure ratio of the two buffer gases. The fractional temperature coefficient of buffer gas shift near 59℃ was about 2×10-11/℃. New temperature control circuit with a temperature stability of about 200μK@2,000s was designed. These two improvements reduced the influence of the temperature fluctuation on the frequency stability due to the buffer gas shift. 3） Set up a laser power stable system with a laser power stability of about 4.7×10-4@2,000s which was improved of an order compared to the case of free run and reduced the influence of laser jitter effectively. 4） Improved the circuit. We designed a new constant current source with a current stability of 3×10-6@10,000s when operated at a cunrrent of 0.5 mA, which reduced the magnatic field jitter. We improved the voltage resolution of the lock-in circuit from 153μV to 9μV with a 20bit DAC, which reduced the voltage noise. In addition, we optimized the parameters. A frequency stability of about 3.53×10-133@1s was obtained and reached to 4.91×10-15@2,000s. This performance is very close to the best performance of POP Rubidium clock all over the world which is presented by INRIM, but the medium-long term longer than 2,000s of our POP clock is worse than theirs which we attributed it to the temperature fluctuation. In addition to optimizing the performance, we also carried out the research on new technologies that may improve the performance of POP Rubidium clock. We studied on the nondestructive detection with far-off-resoant laser and orthogonal polarization detection. We studied on the microwave phase modulation. Based on this, we realized atomic phase feedback. With positive phase feedback, we got a Ramsey fringe with a linewidth been narrowed. With a negative phase feedback, we got a Ramsey fringe with the linear region not been narrowed. And this work lays a foundation for the subsequent experiment of atomic phase lock. |
| 学科主题 | 光学工程 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/30985]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 董功勋. 基于正交偏振探测技术的POP铷原子钟性能优化[D]. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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