漫反射光场中原子的激光冷却和非线性光谱研究
文献类型：学位论文
| 作者 | 张文卓 |
| 学位类别 | 博士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 王育竹 |
| 关键词 | 光冷却 积分球 漫反射光场 各向同性冷却 冷原子 非线性光谱 反冲诱导共振 电磁诱导吸收。 |
| 其他题名 | Study of the laser cooling and nonlinear spectroscopy of atoms in diffuse light |
| 中文摘要 | 本学位论文内容为作者博士期间的两项主要工作，一项为积分球内漫反射光场中原子的激光冷却，另一项为积分球内漫反射光场中冷原子的非线性激光光谱。 原子的漫反射光冷却技术是有别于光学粘胶和磁光阱（MOT）的一种激光冷却技术，它是利用原子在漫反射光场中存在大速度范围的共振来对原子进行大速度范围的多普勒冷却。同时由于存在双光子共振，以及积分球内漫反射激光的偏振和光强的不均匀，它还可以对原子产生亚多普勒冷却。它的特点是设备简约，集成，不需要庞大高功耗的磁场装置，因此这项冷却技术对冷原子物理和冷原子钟技术具有重要意义，尤其适合小型化空间冷原子物理和空间原子钟的研究。我们首先通过理论研究给出了漫反射光场多普勒冷却和亚多普勒冷却的机制，然后在实验上成功地从铷87原子蒸汽中直接冷却了原子数达到10G量级，温度低于100$\mu$K的铷87原子，获得了信噪比很高的冷原子吸收信号。同时研究了双频漫反射光对铷87原子的冷却，为积分球内漫反射光冷却技术在各类冷原子物理实验中的应用提供了物理基础和关键技术。 冷原子的非线性激光光谱在光学粘胶和磁光阱（MOT）中曾得到广泛研究，为冷原子物理的一个研究热点。但是在漫反射光场中，冷原子的非线性激光光谱学并未得到广泛的研究和关注。通过研究和分析冷原子在漫反射光场中会被偏振方向随机的漫反射光泵浦的特点，我们给出了漫反射光场中冷原子最可能产生的两种非线性激光光谱，即光子反冲诱导共振（RIR）光谱和电磁诱导吸收（EIA）光谱在漫反射泵浦光条件下的理论模型和计算结果。实验中我们在国际上首次观测到了漫反射光场中铷87原子的非线性激光光谱，该光谱即为光子反冲诱导共振（RIR）光谱和电磁诱导吸收（EIA）光谱的合成。在考虑积分球内光场强度分布后，我们这两种光谱的理论结算结果和实验观测结果达到很好的符合。这项研究为原子的漫反射光冷却技术在冷原子物理中的应用开辟了一个新的课题，使积分球内漫反射光冷却不只 局限在空间冷原子钟研究中，同时会在冷原子物理其他领域当中能发挥重要作用。 |
| 英文摘要 | This thesis includes two topics that the author got involved in his PhD studies. One is the laser cooling of atoms in diffuse light in an integrating sphere, the other is the nonlinear spectroscopy of cold atoms in the diffuse light. Both theoretical studies and experimental results are presented in this thesis. Cooling of atoms in diffuse light (diffuse cooling) is a laser cooling technique besides the optical molasses and the magneto-optical trap (MOT). The diffuse light can cool a large number of atoms due to its wide resonance velocity-range between the diffuse light and the atoms. It has both Doppler cooling and sub-Doppler cooling effect. The advantages of the diffuse cooling technique are its simple and compact set-up, and no magnetic field. Therefore, it benefits both cold atom physics and cold atom clock studies, especially the compact set-up for space cold atom physics and space cold atom clock. We studied the theory and mechanism of laser cooling of atoms in diffuse light, and present the experiment of cooling Rubidium 87 atoms in an integrating sphere, which shows that cold 87Rb atoms with number of the order 10G and the temperature lower than 100 micro Kelvin can be obtained. We also studied cooling of atoms in two-frequency diffuse light, which benefits the application of diffuse cooling technique in the cold atom physics studies. The nonlinear spectroscopy of cold atoms is a hot research topic and has been widely studied in optical molasses and magneto-optical trap (MOT). However, it has been rarely concerned and studied in the diffuse light case. With studying the feature of cold atoms in a fully depolarized diffuse-light pump field, we present the theoretical model of the recoil-induced resonances (RIR) and the electromagnetically induced absorption (EIA), which are the two most probable physical processes that can cause nonlinear spectra of cold atoms in diffuse light. We experimentally observed the nonlinear spectral signal of cold 87Rb atoms in diffuse light in an integrating sphere, which is the first observation of nonlinear spectra of cold atoms in the diffuse cooling system. The nonlinear spectral signal can decompose to the recoil-induced resonances (RIR) signal and the electromagnetically induced absorption (EIA) signal. When considering the distribution of the light intensity in our integrating sphere, our theoretical result matches the experimental signal well. Our work opens new research possibility of cooling atoms in diffuse light, which shows the diffuse cooling technique is not only useful in compact space cold atom clock study, but also useful in other topics of cold atom physics. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15285]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 张文卓. 漫反射光场中原子的激光冷却和非线性光谱研究[D]. 中国科学院上海光学精密机械研究所. 2009. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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