相干布居囚禁原子钟和磁强计的差分探测研究

发布时间：2018-01-05 05:28

本文关键词：相干布居囚禁原子钟和磁强计的差分探测研究　出处：《中国科学院研究生院(武汉物理与数学研究所)》2016年硕士论文　论文类型：学位论文

【摘要】：相干布居囚禁(Coherent Population Trapping,CPT)是一种量子干涉效应,在原子钟和原子磁强计的研制中有着重要应用。本文针对提高CPT原子钟的短期稳定度和CPT磁强计的灵敏度分别进行了实验研究。以下是本文的研究成果：1、将以左、右旋光为光源的方案(σ+σ+-σ-σ-)应用于芯片原子钟(Chip Scale Atomic Clock,CSAC)所用的微型原子气泡,研究了该方案在CSAC研制中的应用潜力。该方案提高了原子利用率,与传统方案相比所获CPT信号对比度改善3倍。2、对垂直线偏振方案(lin⊥lin)所用的正交偏振仪进行了改进。改进后的正交偏振仪体积减小,且提高了系统的机械稳定性,有望将其应用于CSAC的研制,来提高CSAC的短期稳定度。3、对己提出的平行线偏振方案(lin‖lin)做了进一步研究,探讨了该方案在提高CPT原子钟稳定度方面的可行性和应用潜力。研究结果揭示：虽然该方案可以提高CPT信号的对比度,但由于该方案需要将激光频率锁定在87Rb原子D1线激发态的Fe=1的吸收谱线上,而该谱线较小,因此当CPT信号幅度太大时将难以进行激光锁频,且CPT信号的噪声会明显增大。4、研究了偏振相互垂直的两束线偏振光与87Rb原子相互作用后,同时存在干涉效应和旋光效应的CPT谱线。实验中采用前面改进后的正交偏振仪得到了偏振方向相互垂直的多色线偏振光,通过改变一束光的光程而改变两光束的光程差,将光程差定在最佳值处,差分探测得到了高信噪比的CPT吸收谱线和色散谱线。利用该方案具有将CPT原子钟的短期稳定度提高3倍以上的潜力。5、提出了基于差分探测磁旋光信号的CPT磁强计方案(DMOR-CPT磁强计)。DMOR-CPT磁强计方案采用线偏振光,并用差分探测技术探测线偏振光与原子作用后的磁旋光信号。该方案可将灵敏度提高半个量级,同时其弱磁场探测能力也提高了一倍,而且其装置简单,有望实现小型CPT磁强计。
[Abstract]:Coherent population trapping (Population) is a quantum interference effect. It has important applications in the development of atomic clock and atomic magnetometer. In this paper, the short-term stability of CPT atomic clock and the sensitivity of CPT magnetometer are studied experimentally. :. 1. The scheme (蟽-蟽-蟽-蟽-蟽-蟽 -) with left and right turn light as light source is applied to chip Scale Atomic Clock. The application potential of this scheme in the development of CSAC has been studied, and the atomic utilization rate has been improved by using the micro atomic bubble used in CSAC. Compared with the traditional scheme, the contrast of the CPT signal obtained is improved by 3 times. 2. The orthogonal polarimeter used in the vertical line polarization scheme is improved. The volume of the improved orthogonal polarimeter is reduced. The mechanical stability of the system is improved, which is expected to be applied to the development of CSAC to improve the short-term stability of CSAC. 3. The parallel line polarization scheme proposed by us is further studied. The feasibility and application potential of this scheme in improving the stability of CPT atomic clock are discussed. The results show that the scheme can improve the contrast of CPT signals. However, the scheme needs to lock the laser frequency on the absorption line of Fe=1 in the excited state of 87Rb D1 line, which is small, so it will be difficult to lock the laser frequency when the amplitude of CPT signal is too large. The noise of CPT signal will increase obviously. 4. The interaction of two beam line polarized beams with 87Rb atom is studied. At the same time, there are interference effect and optical rotation effect in CPT spectra. In the experiment, the polarization direction is perpendicular to each other by using the improved orthogonal polarimeter. By changing the optical path of a beam of light and changing the optical path difference of two beams, the optical path difference is determined at the optimum value. The CPT absorption and dispersive spectral lines with high SNR are obtained by differential detection. The proposed scheme has the potential of increasing the short-term stability of CPT atomic clock by more than 3 times. A scheme of CPT magnetometer based on differential detection of magnetic rotation signal is presented. The scheme of DMOR-CPT magnetometer adopts linear polarization. The differential detection technique is used to detect the magneto-optical signal after the interaction between the linear polarized light and the atom. This scheme can increase the sensitivity by half an order of magnitude, at the same time, the detection ability of the weak magnetic field is doubled, and the device is simple. It is expected to realize a small CPT magnetometer.
【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】：硕士
【学位授予年份】：2016
【分类号】：TM935.115

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