近三十年来，随着激光技术的发展，强场原子物理的研究取得了巨大的进展。虽然迄今为止对惰性气体的强场物理研究已经很普遍，但是对于其他种类的原子仍然缺乏系统性的研究。本项目拟针对金屬原子尤其是碱金属及碱土金属这两类原子展开研究。首先，它们的低电离势使其适用于用相对较“弱”的激光场来探索强场物理效应，从而能更深入的理解强场物理中基础概念的普遍适用性。此外，由于它们拥有一些振子强度高且跟基态能量差距不大的低阶激发态，使其在研究激发态在强场电离中的作用上能成为极具吸引力的目标。本項目将主要研究这些原子在近红外至中红外波段飞秒激光照射下所產生的強場現象并与惰性气体中的对应结果作出比较，找出它们的异同。此项目不但有助于深入理解这两类原子与强场的相互作用机制，而且对于强场原子物理基础的整体发展也帶來幫助。

Thanks to the development of ultrafast laser technologies, tremendous advancement in strong-field atomic physics has been taking place over the last three decades. While noble gas atoms have been extensively studied so far, systematic investigations on other kinds of atoms are still lacking. This proposal focuses on strong-field studies of metal atoms, especially for alkali and alkaline earth metals. First, their low ionization potentials make them suitable for exploring strong-field phenomena with relatively “weak” laser fields, which will lead to a more in-depth understanding in the universality of the fundamental concepts in strong-field physics. Also, these atoms are attractive targets for studying the roles of excited states in strong-field ionization, since they possess low-lying excited states which have strong oscillator strengths and are energetically close to the ground states. We will focus on the strong-field phenomena of these atoms irradiated by near- and mid-infrared fields. We will compare them with corresponding measurements on noble gases and identify the similarities and differences. Our proposed research not only lead to deeper understanding of the interactions between these two kinds of atoms and intense laser, but also benefits the fundamental development of strong-field physics.