We present an evaporative cooling technique for atoms trapped in an optical dipole trap that benefits from narrow optical transitions. For an appropriate choice of wavelength and polarization, a single laser beam leads to opposite light shifts in two internal states of the lowest-energy manifold. Radio-frequency coupling between these two states results in evaporative cooling at a constant trap stiffness. The evaporation protocol is well adapted to several atomic species, in particular to the case of Lanthanides such as Er, Dy, and fermionic Yb, but also to alkali-earth metals such as fermionic Sr. We derive the dimensionless expressions that allow us to estimate the evaporation efficiency. As a concrete example, we consider the case of ${}^{162}\mathrm{Dy}$ and present a numerical analysis of the evaporation in a dipole trap near the $J^{\prime }=J$ optical transition at $832\mathrm{n}\mathrm{m}$. We show that this technique can lead to runaway evaporation in a minimalist experimental setup.

中文翻译：

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光偶极阱中的射频蒸发

我们提出了一种用于捕获在光学偶极陷阱中的原子的蒸发冷却技术，该技术受益于窄光学跃迁。For an appropriate choice of wavelength and polarization, a single laser beam leads to opposite light shifts in two internal states of the lowest-energy manifold. 这两种状态之间的射频耦合导致在恒定阱刚度下蒸发冷却。蒸发协议非常适用于几种原子种类，特别是镧系元素的情况，例如 Er、Dy 和费米子 Yb，也适用于碱土金属，例如费米子 Sr。我们推导出无量纲表达式，使我们能够估计蒸发效率。作为一个具体的例子，我们考虑以下情况${}^{162}\mathrm{染料}$ 并给出了附近偶极阱中蒸发的数值分析 $J^{\prime }=J$ 光学跃迁 $832\mathrm{n}\mathrm{米}$. 我们表明，这种技术可以在极简的实验设置中导致失控的蒸发。