Metastable D-state spectroscopy and laser cooling of barium
Metastable D-state spectroscopy and laser cooling of barium
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钡的亚稳态 D 态光谱和激光冷却
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发表时间：
2006
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通讯作者：
U. Dammalapati
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作者：
U. Dammalapati
本论文是作为TRImP计划的一部分编写的。稀有和短寿命的放射性同位素为研究基本相互作用和对称性提供了新的可能性。镭是一种放射性碱土金属元素，被认为是寻找中性原子永久电偶极矩的新候选元素。荷兰格罗宁根KVI的TRImP设施正在建立，以生产和利用这些放射性同位素来研究基本的相互作用和对称性。我们使用原子阱进行这些研究。我们介绍了在TRImP设施生产、分离和减缓我们感兴趣的短寿命放射性同位素的各个阶段。我们需要将激光冷却和捕获方法扩展到重碱土元素钡和镭。稳定的钡非常适合作为放射性镭的前体，因为它具有相似的能级结构和化学性质。由于镭的放射性，我们选择用同系物钡来制备冷却和捕获。本研究中使用了钡的稳定同位素。对于光谱学，亚稳态单重态和三重态D-态是通过光学方法而不是使用传统的原子放电方法来填充的。通过驱动1 S 0 - 1 P1跃迁来填充单态D态。为了有效地填充三重态D-态，利用3 P1能级的分支比，通过使用791.3 nm的二极管激光器的互组合线进行光泵浦。这些激光器的长期频率稳定性是通过将频率参考到分子碘中的附近跃迁来实现的。我们分别对1D 2 - 1 P1（1500.4 nm）、3D 1 - 1 P1（1107.8 nm）和3D 2 - 1 P1（1130.6 nm）跃迁进行了第一次直接光谱分析。光学解析了Ba-135，137同位素3D 1和3D 2能级的超精细结构。此外，还测量了3D 1 - 1 P1跃迁的同位素位移。本文报道了钡原子相干拉曼共振的实验观察。提取了λ系统的相关拉比频率，并估计了与激光冷却实验相关的跃迁速率。我们首次实现了钡原子束的慢化。这些结果可以应用于原子，其中只有在不同波长的几个激光场下才能发现封闭的冷却循环。
This thesis is written as a part of the TRImP programme. Rare and short-lived radioactive isotopes offer new possibilities for investigating fundamental interactions and symmetries. Radium, a radioactive alkaline earth element has been identified as a new candidate for searches for a permanent electric dipole moment in neutral atoms. The TRImP facility at KVI, Groningen, The Netherlands is being setup to produce and utilize these radioactive isotopes to study fundamental interactions and symmetries. We use atom traps for these studies. We presented the various stages for the production, separation and slowing of the short-lived radioactive isotopes of our interest at the TRImP facility. We need to expand laser cooling and trapping methods to heavy alkaline earth elements barium and radium. Stable barium is well suited as a precursor for radioactive radium, because of its similar level scheme and chemical properties. Because of the radioactivity of radium we have chosen to prepare the cooling and trapping with the homologue barium. Stable isotopes of barium were used in the present study. For spectroscopy, metastable singlet and triplet D-states were populated by optical methods rather than using the conventional method of atomic discharges. The singlet D-state is populated by driving the 1S0-1P1 transition. To populate the triplet D-states efficiently the branching ratio of the 3P1 level was exploited by optical pumping with the intercombination line using the diode lasers at 791.3 nm. Long term frequency stability of these lasers were achieved by referencing the frequency to a nearby transition in molecular iodine. We performed first direct optical spectroscopy of the 1D2-1P1(1500.4 nm), 3D1-1P1(1107.8 nm) and 3D2-1p1 (1130.6 nm) transitions respectively. The hyperfine structure of the 3D1 and 3D2 levels for the Ba-135,137 isotopes were optically resolved. In addition, isotope shifts of the 3D1-1P1 transition were measured. We report the experimental observation of coherent Raman resonances in barium. The relevant Rabi frequencies were extracted for the lambda system and estimated the transition rates, relevant for the laser cooling experiment. We have achieved the first slowing of a barium atomic beam. These results can be applied for atoms, in which a closed cooling cycle can only be found with several laser fields at different wavelengths.