通过共线激光光谱学中的级联光泵浦从强基态背景中高效分离同质异能态$^{26\text{m}}\text{Al}$
Efficient Separation of the Isomeric State $^{26\text{m}}\text{Al}$ from the Intense Ground State Background via Sequential Optical Pumping in Collinear Laser Spectroscopy
AI总结：
本研究基于共线激光光谱学，通过级联光泵浦技术，利用2.0米飞行区的光泵浦和47能级速率方程，实现了从基态$^{26\text{g}}\text{Al}$背景中高效分离同质异能态$^{26\text{m}}\text{Al}$，获得无背景的高强度共振峰。
AI中文摘要：
我们提出了一种新颖的高效方法，利用共线激光光谱学（CLS）中2.0米飞行区的光泵浦，从占绝对优势的基态$^{26\text{g}}\text{Al}$背景（同质异能态比例约20:1）中分离出同质异能态$^{26\text{m}}\text{Al}$。为研究潜在的光泵浦（OP）动力学，我们开发了一套完整的速率方程框架。虽然跃迁路径可通过初级7流形方案直观概念化，但我们的数值模拟求解了完整的47能级速率方程，明确考虑了所有简并塞曼子能级（$m_F$），以严格纳入偏振选择定则和 Clebsch-Gordan 系数。当连续加速电压与$^{26\text{g}}\text{Al}$超精细跃迁的共振条件匹配时，基态原子在2.0米飞行区内以100%效率跃迁为非耦合暗态。因此，基态的背景荧光在探测室中被完全抑制，而$^{26\text{m}}\text{Al}$原子利用闭合循环结构在飞行区内留存，产生高强度、无背景的共振峰。
英文摘要：
We propose a novel, highly efficient method for isolating the isomeric state $^{26\text{m}}\text{Al}$ from an overwhelming ground-state $^{26\text{g}}\text{Al}$ background (isomeric ratio $\sim 20:1$) using optical pumping through a 2.0 m flight zone in collinear laser spectroscopy (CLS). To investigate the underlying optical pumping (OP) dynamics, we developed a comprehensive rate equation framework. While the transition pathways can be intuitively conceptualized via a primary 7-manifold scheme, our numerical simulation solves the full 47-level rate equations by explicitly accounting for all degenerate Zeeman sublevels ($m_F$) to rigorously incorporate polarization selection rules and Clebsch-Gordan coefficients. When the continuous acceleration voltage matches the resonance conditions of the $^{26\text{g}}\text{Al}$ hyperfine transitions, the ground-state atoms undergo a 100% efficient transition into uncoupled dark states within the 2.0 m flight zone. Consequently, background fluorescence from the ground state is completely suppressed in the detection chamber, whereas $^{26\text{m}}\text{Al}$ atoms utilize a closed cycling structure to survive the flight zone, yielding a high-intensity, background-free resonance peak.
