锂原子的冷却囚禁及相干操控实验研究

发布时间：2018-06-20 19:20

本文选题：弱等效原理 + 磁光阱　；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】：作为原子序数最小的碱金属元素,锂原子具有质量小、反冲速度大的特点。利用锂原子做干涉仪可以增大环路面积,有利于对反冲能量和精细结构常数的测量。另外,选择锂原子进行弱等效原理的检验也有着广阔的前景。然而,由于锂原子特殊的能级结构,传统的亚多普勒方法很难在锂原子上面奏效,这也是影响锂原子干涉仪发展最主要的困难。本学位论文以研制锂的冷原子干涉仪为目标,在原子的冷却与囚禁,亚多普勒冷却,拉曼跃迁与Rabi振荡等方面对7Li原子做了相关的一系列实验研究,取得的主要创新性研究工作有以下几个方面：(1)原子源的获取：实现了塞曼减速器的安装调试,成功将原子从700 m/s预减速到70 m/s；之后与磁光阱结合起来,获得了锂原子的磁光阱信号；并在此基础上对原子数(1.2x109)以及原子团温度进行了测量,利用压缩磁光阱将原子温度进一步降低到220±30μK。(2)尝试使用了两种新的亚多普勒冷却方案：西西弗斯冷却(Sisyphus cooling)和灰色黏胶冷却(Gray molasses cooling)。其中利用西西弗斯冷却方案成功完成了锂原子的一维亚多普勒冷却；利用灰色黏胶冷却方案完成了对一维灰色黏胶的抓捕。(3)进行了初步的锂原子干涉仪的探索：利用单光子失谐为1.6 GHz的拉曼光实现了同向受激拉曼跃迁,得到了拉曼共振峰,共振峰的中心位置在803.518 MHz,半高宽为16.6 kHz；在此基础上对脉冲时间进行扫描,得到了Rabi振荡曲线,从而获得了明确的π光时间。(4)针对实验中的需求,设计了一种可同时输出多种不同偏振态激光的扩束镜系统,在实验中起到了重要作用。(5)为了满足实验中对拉曼光稳频的需要,详细研究了锂原子的调制转移谱,并成功完成了拉曼光的锁定。
[Abstract]:As the element of alkali metal with the smallest atomic number, lithium atom has the characteristics of small mass and high recoil speed. The area of the loop can be increased by using lithium atom as interferometer, which is beneficial to the measurement of recoil energy and fine structure constant. In addition, the selection of lithium atoms to test the principle of weak equivalence also has a broad prospect. However, because of the special energy level structure of lithium atom, the traditional sub-Doppler method is difficult to work on lithium atom, which is also the main difficulty to affect the development of lithium atom interferometer. In this dissertation, a series of experimental studies have been carried out on 7Li atoms in the aspects of atomic cooling and trapping, sub-Doppler cooling, Raman transition and Rabi oscillation, aiming at the development of a cold atom interferometer for lithium. The main innovative work achieved was the acquisition of atomic sources in the following aspects: the installation and commissioning of the Zeeman Reducer, the successful pre-deceleration of the atom from 700 m / s to 70 m / s, and the subsequent integration with the magneto-optic trap. The magneto-optic trap signal of lithium atom is obtained, and the atomic number (1.2x109) and the temperature of the atom cluster are measured. Two new subDoppler cooling schemes, Sisyphus cooling (Sisyphus cooling) and grey viscose cooling (Gray molasses cooling), were used to further reduce the atomic temperature to 220 卤30 渭 K. Among them, the Sisyphus cooling scheme was used to successfully complete the I-V doppler cooling of lithium atoms. The primary lithium atom interferometer has been explored by using the grey viscose cooling scheme. The one-photon detuned Raman light of 1.6 GHz has been used to realize the codirectional stimulated Raman transition, and the Raman resonance peak has been obtained. The central position of the resonance peak is 803.518 MHz and the width of the half peak is 16.6 kHz. On this basis, the pulse time is scanned, and the Rabi oscillation curve is obtained, thus obtaining a definite 蟺 light time. A beam expander system is designed, which can output different kinds of polarized laser simultaneously. It plays an important role in the experiment. In order to meet the need of Raman optical frequency stabilization in the experiment, the modulation and transfer spectra of lithium atom are studied in detail. And successfully completed the locking of Raman light.
【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

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