A scheme is proposed for the third stage of laser cooling of thulium atoms at a wavelength of 506.2 nm, and a system for stabilising the laser radiation frequency is described, which provides the required characteristics. The transition at a wavelength of 506.2 nm is detected in a magneto-optical trap with the employment of the developed laser setup. The value of hyperfine splitting of the transition upper level is measured, and the single-dimension cooling at this wavelength is observed for the first time.

中文翻译：

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研究 506 nm 波长处的跃迁，用于铥原子的深度冷却

提出了波长为 506.2 nm 的铥原子激光冷却第三阶段的方案，并描述了一种稳定激光辐射频率的系统，该系统提供了所需的特性。使用开发的激光装置在磁光陷阱中检测到波长为 506.2 nm的跃迁。测量跃迁上能级的超精细分裂值，首次观察到该波长下的单维冷却。