钛原子的窄线磁光阱
Narrow-line magneto-optical trap of titanium atoms
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中文总结 AI 辅助
本文实现了钛原子的窄线磁光阱，利用1040 nm跃迁冷却至亚微开温度，通过两阶段操作和斯特恩-盖拉赫分离，测得98%原子处于拉伸自旋态。
中文摘要 AI 辅助
我们基于1040 nm波长的跃迁实现了$^{46}$Ti、$^{48}$Ti和$^{50}$Ti原子的窄线宽磁光阱，将原子在一维方向上冷却至最低温度$T_z=990(20)$ nK，三维温度为$T_\mathrm{3D}=1.28(7)$ $\mu$K。原子首先在宽线磁光阱中预冷却，然后以约25%的效率转移到窄线阱中。我们在85 ms内分两个阶段运行窄线阱。首先，一束相对于窄线宽原子共振蓝失谐的单一冷却光束，在二维表面上对原子进行光泵浦和囚禁，其中施加的球形四极磁场产生的塞曼位移使光接近共振。其次，在横向方向上相向传播的四束附加光束，在所有维度上冷却和压缩原子。激光冷却态的高磁矩使得窄线钛阱的动力学与其他磁性原子相似。我们测量了该跃迁激发态的寿命为$\tau=8.2(9)$ $\mu$s，表明跃迁线宽为$\gamma/2\pi =20(2)$ kHz，并测量了窄线跃迁的同位素位移。我们利用超冷钛气体上的斯特恩-盖拉赫分离来测量窄线磁光阱中的$m_J$分布，发现超过98%的原子处于拉伸自旋态。
英文摘要
We realize narrow-linewidth magneto-optical traps of $^{46}$Ti, $^{48}$Ti and $^{50}$Ti atoms based on a 1040 nm-wavelength transition, cooling atoms to a minimum temperature in one dimension of $T_z=990(20)$ nK and a three-dimensional temperature of $T_\mathrm{3D}=1.28(7)$ $μ$K. Atoms are pre-cooled in a broad-line magneto-optical trap and then transferred with about 25% efficiency to the narrow-line trap. We operate the narrow-line trap in two stages over 85 ms. First, a single cooling beam, blue-detuned from the narrow-linewidth atomic resonance, optically pumps and traps the atoms on a two-dimensional surface where the Zeeman shift from the applied spherical quadrupole magnetic field brings the light nearly to resonance. Second, four additional beams, counter-propagating in the transverse directions, cool and compress the atoms in all dimensions. The high magnetic moment of the laser cooling state makes the dynamics of the narrow-line titanium trap similar to those of other magnetic atoms. We measure the lifetime of the excited state of the transition to be $τ=8.2(9)$ $μ$s, indicating a transition linewidth of $γ/2π=20(2)$ kHz, and also measure isotope shifts on the narrow-line transition. We use Stern-Gerlach separation on the ultracold Ti gas to measure the $m_J$-distribution in the narrow-line magneto-optical trap, finding over 98% of the atoms in the stretched spin state.
发表机构
- University of California, Berkeley（加州大学伯克利分校）
- Challenge Institute for Quantum Computation（挑战量子计算研究所）
- Joint Quantum Institute（联合量子研究所）
- National Institutes for Standards and Technology（国家标准与技术研究院）
- Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）
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