玻色－爱因斯坦凝聚的光散射与拉曼喷泉原子钟
文献类型：学位论文
| 作者 | 屈求智 |
| 学位类别 | 硕士 |
| 答辩日期 | 2007 |
| 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 | 玻色爱因斯坦凝聚BEC 光散射 拉曼光场 喷泉原子钟 |
| 其他题名 | Coherent scattering of the Bose-Einstein condensation and Raman fountain atomic clock |
| 中文摘要 | BEC是一种新的物质状态，研究其自身的物理性质以及形成这些性质的物理过程，具有重大的理论意义与应用价值。BEC的实现，是与激光冷却与囚禁技术迅速发展分不开的，激光冷却技术与其它应用技术相结合，产生了许多新的研究领域。本论文在掌握激光冷却与囚禁原理的基础上，利用BEC实验平台研究了BEC在紧束缚状态下的光散射现象，为BEC的相变提供了新的判据。此外，还将冷原子喷泉技术、分离拉曼光场技术和原子频标技术相结合，提出了一种新的原子钟方案――拉曼喷泉原子钟。 1 在实验中观察到了紧束缚状态下BEC的光散射所形成的多级衍射条纹，分析了它产生的原因，并建立了理论计算模型，证实了BEC的光散射符合GDT理论的预言，并论证了多级衍射条纹的显著变化可以作BEC产生的一个重要判据。 2 提出了一种新的原子钟方案，利用拉曼光场代替喷泉原子钟的微波腔实现拉曼喷泉原子钟。这种方案将分离拉曼光场技术与冷原子喷泉技术相结合，避免了在真空腔内放置微波腔，简化了真空系统，同时还能保持很高的准确度。我们采用半经典理论研究了冷原子喷泉与拉曼光场的相互作用过程，得到了Ramsey条纹。我们比较了拉曼喷泉原子钟与热铯束拉曼原子钟，前者有更小的体积和功耗，其精度可能达到或超过商用小铯钟。我们还比较了拉曼喷泉原子钟与微波喷泉原子钟的差别，分析了光子反冲的影响，提出利用同向传播和相向传播的两台拉曼喷泉原子钟测量精细结构常数。 |
| 英文摘要 | Since Bose-Einstein condensation is a new matter state, it is significant for theory and application to investigate its properties and formation process. The reality of BEC is supported by the laser cooling and trapping technology. While the laser cooling and trapping technology is combined with the other application technologies many new study field has been exploited. This thesis study the coherent scattering of the BEC in a tight trap based on the laser cooling and trapping technology and give a new criterion of the BEC phase transition. A new scheme of a Raman atomic fountain clock which combine the separate Raman fields technology and the cold atomic fountain technology with the atomic frequency standard technology is been present in this thesis. 1 We have observed strong scattering of a probe light by dilute Bose-Einstein condensate 87Rb gas in a tight magnetic trap. The scattering light forms fringes at the image plane. We found that we can infer the real size of the condensation and the number of the atoms through modeling the imaging system and presenting a quantitative calculation of the fringes. The calculation shows that the experimental results of light scattering by the condensed atoms agree well with the prediction of generalized diffraction theory, and thus we can directly observe the phase transition of BEC in a tight trap. 2 We present a new scheme of an atomic fountain clock based on a Raman laser field instead of the microwave cavity. This scheme is much simple than the microwave fountain clock in the vacuum cavity which combine the separate Raman fields technology and the cold atomic fountain technology with a high accuracy. We have study the interaction process of the cold atomic fountain and the Raman laser field using the semi classical theory and acquired the Ramsey fringes. We compared the Raman fountain clock with the atomic beam clock of hot cesium atoms, and found that the accuracy of Raman fountain clock would be higher and its capacity and power consumption are much smaller than the other one. Compared with the microwave fountain clock, the Raman fountain clock must consider the influence of the photon recoil, which has been analyzed in this paper. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16592]  |
| 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 | 屈求智. 玻色－爱因斯坦凝聚的光散射与拉曼喷泉原子钟[D]. 中国科学院上海光学精密机械研究所. 2007. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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