光子光栅芯片辅助的锶 ${}^{1}S_{0}\rightarrow{}^{1}P_{1}$ 跃迁频率测量
Strontium ${}^{1}S_{0}\!\rightarrow\!{}^{1}P_{1}$ transition frequency measurements assisted by a photonic grating chip
AI总结：
本研究通过两种方法结合衍射光栅芯片，测得锶 ${}^{1}S_{0}\rightarrow{}^{1}P_{1}$ 跃迁频率为650.503815(5) THz，为对应461 nm跃迁提供了重新评估。
AI中文摘要：
我们采用两种方法测量锶的 ${}^{1}S_{0}\rightarrow{}^{1}P_{1}$ 跃迁的绝对频率：第一种是来自紧凑型低功率烤箱的热原子束源的荧光光谱法，第二种是来自二维光栅磁光阱（2D gMOT）的慢原子束的速度测量法。两种方法的测量均在同一超高真空腔室内进行，该腔室内包含一个衍射光栅芯片，芯片放置于被探测的锶原子下方。第一种方法利用入射到光栅芯片的探测激光束，使光栅充当端镜，一阶衍射光束提供回射探测光束；相向传播的激光束穿过从烤箱发射的原子束，可通过CCD成像和超精细约束的多同位素拟合实现空间分辨的荧光光谱测量。第二种方法依赖于垂直入射到光栅芯片的大口径冷却激光束，该激光束冷却锶原子以作为慢原子束源；测量从2D gMOT出射的原子速度随激光失谐量和强度的变化，由此可估算共振频率。两种方法在各自的测量不确定度范围内一致。基于回射光束光谱测量的三个数据集，以及基于慢原子束速度测量的一个数据集，我们确定 ${}^{1}S_{0}\rightarrow{}^{1}P_{1}$ 跃迁频率为 $650.503815(5)~\text{THz}$。我们的结果为基于衍射光栅平台的紧凑型激光冷却装置上演示的该461 nm跃迁提供了重新评估。
英文摘要：
We measure the absolute frequency of the ${}^{1}S_{0}\!\rightarrow\!{}^{1}P_{1}$ transition in strontium using two methods: fluorescence spectroscopy of a thermal atomic beam source from a compact low-power oven and velocity measurements of a slow atomic beam from a two-dimensional grating magneto-optical trap (2D gMOT). The measurements for both methods are performed in the same ultra-high vacuum chamber containing a diffraction grating chip which is placed below the strontium atoms that are being interrogated. The first method uses a probe laser beam incident on the grating chip such that the grating acts as an end mirror, with the first-order diffracted beam providing a retro-reflected probe beam. The counter-propagating laser beams traverse an atomic beam emitted from an oven, enabling spatially resolved fluorescence spectroscopy through CCD imaging and hyperfine-constrained multi-isotope fitting. The second method relies on a large profile cooling laser beam normally incident onto the grating chip which laser cools strontium atoms for a slow atomic beam source. The velocity of the atoms exiting the 2D gMOT is measured as a function of the laser detuning and intensity from which the resonance frequency can be estimated. The two methods are consistent within their quoted uncertainties. Using three datasets based on retro-beam spectroscopy measurements, and one dataset using slow atom beam velocity measurements, we determine the ${}^{1}S_{0}\!\rightarrow\!{}^{1}P_{1}$ transition frequency to be $650.503\,815(5)~\mathrm{THz}$. Our result provides a re-evaluation of this $461$ nm transition demonstrated on a compact laser cooling apparatus based on a diffraction grating platform.
