论文标题
运动选择性相干种群捕获，用于在羔羊dicke政权外的光学捕获原子的子捕集冷却
Motion-selective coherent population trapping for subrecoil cooling of optically trapped atoms outside the Lamb-Dicke regime
论文作者
论文摘要
我们提出了一个方案，该方案结合了速度选择性相干种群捕获（CPT）和拉曼侧带冷却（RSC），用于在羔羊dicke制度之外的光学捕获原子的子捕获冷却。该方案基于碱原子中的倒置$ \ Mathsf {y} $配置。它由一个$λ$组成，由地面超细级和$ d $过渡之间的两个拉曼过渡形成，允许RSC沿着两条路径和CPT黑暗状态的形成。使用圆形极化陷阱中原子振动频率的状态依赖性差异，我们可以调整$λ$，以使Motional基态成为CPT黑暗状态。我们称此方案运动选择性相干种群捕获（MSCPT）。我们为RSC和MSCPT编写主方程式，并以$^{87} $ rb原子的数值求解在一维光学晶格中时，当Lamb-Dicke参数为1时。尽管MSCPT与RSC相比，MSCPT的稳态缓慢地达到了稳态，前者比后者一致地产生冷原子。数值结果还表明，在有利但可行的条件下，MSCPT在羔羊dicke机制外进行的子恢复冷却是可能的。我们通过计算每个运动状态的相对黑暗来定量解释这种性能。最后，我们讨论了将MSCPT方案应用于光学捕获的双极极性分子的应用，该分子的鲜明偏移和振动频率取决于旋转量子数的变化很大。
We propose a scheme that combines velocity-selective coherent population trapping (CPT) and Raman sideband cooling (RSC) for subrecoil cooling of optically trapped atoms outside the Lamb-Dicke regime. This scheme is based on an inverted $\mathsf{Y}$ configuration in an alkali-metal atom. It consists of a $Λ$ formed by two Raman transitions between the ground hyperfine levels and the $D$ transition, allowing RSC along two paths and formation of a CPT dark state. Using state-dependent difference in vibration frequency of the atom in a circularly polarized trap, we can tune the $Λ$ to make only the motional ground state a CPT dark state. We call this scheme motion-selective coherent population trapping (MSCPT). We write the master equations for RSC and MSCPT and solve them numerically for a $^{87}$Rb atom in a one-dimensional optical lattice when the Lamb-Dicke parameter is 1. Although MSCPT reaches the steady state slowly compared with RSC, the former consistently produces colder atoms than the latter. The numerical results also show that subrecoil cooling by MSCPT outside the Lamb-Dicke regime is possible under a favorable, yet experimentally feasible, condition. We explain this performance quantitatively by calculating the relative darkness of each motional state. Finally, we discuss on application of the MSCPT scheme to an optically trapped diatomic polar molecule whose Stark shift and vibration frequency exhibit large variations depending on the rotational quantum number.
