Magneto-optical trapping of a diatomic molecule
Magneto-optical trapping of a diatomic molecule
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DOI：
10.1038/nature13634
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发表时间：
2014-08-21
期刊：
影响因子：
64.8
通讯作者：
DeMille, D.
中科院分区：
文献类型：
--
作者：
Barry, J. F.;McCarron, D. J.;DeMille, D.
激光冷却和捕获是现代原子物理学的核心。冷原子物理学中最常用的技术是磁光陷阱（MOT），它将激光冷却与辐射压力的恢复力结合起来。对于各种原子种类，MOT 可以捕获大量粒子并将其冷却至超冷温度（低于 1 毫开尔文）；这使得从光学时钟到超冷碰撞研究等领域取得了进展，同时也成为进一步冷却到量子简并状态的普遍起点。分子的磁光捕获可以为超冷分子气体的研究和操纵提供同样强大的起点。与分子振动和旋转相关的额外自由度，特别是其永久电偶极矩，允许超冷原子不可能实现的广泛应用(1)。在这些想法的推动下，人们开发出了多种方法来制造超冷分子。由预冷却碱原子组装而成的双原子分子的温度已被证明低于 1 微开尔文 (2,3)，但对于更广泛的适合直接冷却和捕获的物种，直到最近才达到低于 100 毫开尔文的温度 (4,5)。分子复杂的内部结构使磁光捕获变得复杂。然而，最近已经开发出了创建分子 MOT 所需的想法和方法(6-11)。在这里，我们展示了双原子分子一氟化锶 (SrF) 在大约 2.5 毫开尔文温度下的三维磁光捕获，这是通过分子直接冷却实现的最低温度。该方法是原子技术的直接扩展，预计适用于大量双原子物种 (6,7)。随着进一步的发展，我们预计该技术可以用于任何数量的现有和拟议的分子实验，其应用范围从精密测量（12）到量子模拟（13）和量子信息（14）到超冷化学（15）。
Laser cooling and trapping are central to modern atomic physics. The most used technique in cold-atomphysics is the magneto-optical trap (MOT), which combines laser cooling with a restoring force from radiation pressure. For a variety of atomic species, MOTs can capture and cool large numbers of particles to ultracold temperatures (less than similar to 1 millikelvin); this has enabled advances in areas that range fromoptical clocks to the study of ultracold collisions, while also serving as the ubiquitous starting point for further cooling into the regime of quantum degeneracy. Magneto-optical trapping of molecules could provide a similarly powerful starting point for the study and manipulation of ultracold molecular gases. The additional degrees of freedom associated with the vibration and rotation of molecules, particularly their permanent electric dipole moments, allow a broad array of applications not possible with ultracold atoms(1). Spurred by these ideas, a variety of methods has been developed to create ultracold molecules. Temperatures below 1 microkelvin have been demonstrated for diatomic molecules assembled from pre-cooled alkali atoms(2,3), but for the wider range of species amenable to direct cooling and trapping, only recently have temperatures below 100 millikelvin been achieved(4,5). The complex internal structure of molecules complicates magneto-optical trapping. However, ideas and methods necessary for creating a molecular MOT have been developed(6-11) recently. Here we demonstrate three dimensional magneto-optical trapping of a diatomic molecule, strontium monofluoride (SrF), at a temperature of approximately 2.5 millikelvin, the lowest yet achieved by direct cooling of a molecule. This method is a straightforward extension of atomic techniques and is expected to be viable for a significant number of diatomic species(6,7). With further development, we anticipate that this techniquemay be employed in any number of existing and proposed molecular experiments, in applications ranging from precision measurement(12) to quantum simulation(13) and quantum information(14) to ultracold chemistry(15).