论文标题
钙单氢化物分子的直接激光冷却
Direct laser cooling of calcium monohydride molecules
论文作者
论文摘要
我们展示了一氢化钙（CAH）分子的低温缓冲液束的光学循环和亚多普勒激光冷却。 We measure vibrational branching ratios for laser cooling transitions for both excited electronic states A and B. We measure further that repeated photon scattering via the $A\leftarrow X$ transition is achievable at a rate of $\sim$ $1.6\times10^6$ photons/s and demonstrate the interaction-time limited scattering of $\sim$ $200$ photons by repumping the largest vibrational decay channel.我们还证明了通过磁辅助的sisyphus效应将CAH的分子束降低的能力。使用一波光线，我们将分子梁的横向温度从$ 12.2（1.2）$ MK降低到$ 5.7（1.1）$ MK。我们将这些结果与使用光学BLOCH方程和分子束轨迹的蒙特卡洛模拟建模的子多普勒力进行了比较。这项工作为创建CAH分子的磁光陷阱（MOT）建立了清晰的途径。这样的MOT可以作为通过被困的CAH云解离生产超速氢气的起点。
We demonstrate optical cycling and sub-Doppler laser cooling of a cryogenic buffer-gas beam of calcium monohydride (CaH) molecules. We measure vibrational branching ratios for laser cooling transitions for both excited electronic states A and B. We measure further that repeated photon scattering via the $A\leftarrow X$ transition is achievable at a rate of $\sim$ $1.6\times10^6$ photons/s and demonstrate the interaction-time limited scattering of $\sim$ $200$ photons by repumping the largest vibrational decay channel. We also demonstrate the ability to sub-Doppler cool a molecular beam of CaH through the magnetically assisted Sisyphus effect. Using a standing wave of light, we lower the molecular beam's transverse temperature from $12.2(1.2)$ mK to $5.7(1.1)$ mK. We compare these results to sub-Doppler forces modeled using optical Bloch equations and Monte Carlo simulations of the molecular beam trajectories. This work establishes a clear pathway for creating a magneto-optical trap (MOT) of CaH molecules. Such a MOT could serve as a starting point for production of ultracold hydrogen gas via dissociation of a trapped CaH cloud.
