一维光晶格中镱原子光频钟跃迁谱的研究

发布时间：2018-05-18 00:24

本文选题：镱原子 + 原子光钟　；参考：《中国科学院研究生院(武汉物理与数学研究所)》2016年博士论文

【摘要】：近年来,中性原子光晶格钟的研究取得了飞速的进展,其稳定度和不确定度都已进入10-18量级,全面超越了作为国际秒定义的铯喷泉钟。高精度的光钟不仅是守时授时、全球定位导航领域中的关键技术,而且在精密测量物理等基础研究领域有重要的应用价值。171Yb原子是光频标(光钟)重要候选之一,其钟跃迁自然线宽小于10mHz。目前,镱原子光晶格钟稳定度已达到1.6×10-18,其不确定度有望进入10-19量级。研究生期间,我在前期镱原子磁光囚禁工作基础上,进一步实现了镱原子的魔幻波长光晶格装载,并在光晶格中实现了Hz量级超窄线宽钟跃迁谱线的探询。本论文总结了我的主要研究工作介绍如下,1、改进了399nm和556nm冷却光锁频系统。分别通过调制转移谱方案、PDH+荧光谱锁频方案实现399nm激光器和556nm激光器的锁频,使激光频率抖动远小于自然线宽,长期锁定达5天以上,满足光钟实验对激光频率稳定度的要求。2、实现了镱原子魔幻波长光晶格的高效装载。通过对冷原子云温度、密度的控制,在典型实验参数下,镱原子的装载效率达到2%,装载数目达到5×104以上；原子在光晶格中的寿命长达5s。3、实现了镱原子钟跃迁的运动边带谱探测。利用归一化探测技术获得了高信噪比的运动边带谱；通过对谱线线型的分析,得到光晶格阱深为83μK,原子纵向温度为35μK,横向温度为281-μK。4、实现了Hz量级线宽的钟跃迁谱的Rabi探询。利用补偿杂散磁场,抑制功率增宽、自旋极化等关键技术,成功将钟跃迁谱线宽从kHz量级压窄到Hz量级。在170ms探测时间下获得5.9Hz的钟跃迁谱,接近傅里叶极限线宽。5、对镱原子光钟非破坏探测进行了初步研究。实验上精确测量了171Yb原子1S0-3P1互组合跃迁在光晶格中的AC Stark频移,并依据测量结果对基于该跃迁的非破坏探测方案可行性进行理论分析。
[Abstract]:In recent years, the research of neutral atomic optical lattice clock has made rapid progress, its stability and uncertainty have entered the order of 10-18, which is beyond the cesium fountain clock, which is defined as an international second. High precision light clock is not only the key technology in the field of punctuality and GPS navigation, but also has important application value in the basic research fields such as precision measurement physics. 171Yb atom is one of the important candidates for optical frequency standard (optical clock). The natural linewidth of the bell transition is less than 10mHz. At present, the stability of ytterbium atomic optical lattice clock has reached 1.6 脳 10 ~ (-18), and its uncertainty is expected to reach the order of 10-19. During the post-graduate period, based on the previous work of magneto-optical trapping of ytterbium atom, I further realized the magic wavelength optical lattice loading of ytterbium atom, and realized the exploration of the transition line of Hz ultra-narrow linewidth clock in the optical lattice. This paper summarizes my main research work as follows: 1. Improve the 399nm and 556nm cooling optical frequency locking system. The frequency locking of 399nm laser and 556nm laser is realized by modulation transfer spectrum scheme and fluorescence spectrum scheme respectively. The frequency jitter is much smaller than the natural linewidth, and the long-term locking is more than 5 days. To meet the requirement of laser frequency stability in optical clock experiment, the high efficiency loading of ytterbium atom magic wavelength optical lattice is realized. By controlling the cloud temperature and density of cold atoms, under typical experimental parameters, the loading efficiency of ytterbium atoms is 2 and the loading number is more than 5 脳 10 ~ 4, and the lifetime of atoms in optical lattice is up to 5s. 3. The detection of the ytterbium clock transition by moving sideband spectrum is realized. The moving sideband spectrum with high SNR is obtained by normalized detection technique, and the Rabi probe of the clock transition spectrum with Hz linewidth is realized by analyzing the spectral line pattern, the depth of the optical lattice well is 83 渭 K, the longitudinal temperature of the atom is 35 渭 K, and the transverse temperature is 281- 渭 K. 4. By compensating the stray magnetic field and restraining the power broadening and spin polarization, the line width of the clock transition spectrum is reduced from kHz to Hz. The clock transition spectrum of 5.9Hz is obtained at 170ms detection time, which is close to the Fourier limit line width. 5. The nondestructive detection of ytterbium atomic clock is preliminarily studied. The AC Stark frequency shift of 171Yb atom 1S0-3P1 combinatorial transition in optical lattice has been accurately measured experimentally, and the feasibility of the nondestructive detection scheme based on this transition has been theoretically analyzed according to the measured results.
【学位授予单位】：中国科学院研究生院(武汉物理与数学研究所)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O562;TM935.115

【参考文献】