School of Physics and State Key Laboratory for Mesoscopic Physics, Peking University, Beijing 100871, China.
Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
Phys Rev Lett. 2018 Jan 26;120(4):043201. doi: 10.1103/PhysRevLett.120.043201.
We perform a joint experimental and theoretical study on momentum- and energy-resolved photoelectron spin polarization in multiphoton ionization of Xe atoms by circularly polarized fields. We experimentally measure the photoelectron momentum distributions of Xe atoms in circularly polarized near-infrared (800 nm) and ultraviolet (400 nm) light, respectively. We analyze the momentum- and energy-resolved photoelectron spin polarization by comparing the experimental photoelectron momentum distributions with the simulations, although we cannot derive the spin polarization solely from the experiment. We show that the use of circularly polarized ultraviolet light at 400 nm can create better than 90% spin polarization with focal volume effect considered, which enables the separation of the spin states by momentum gating. This paves the way to produce high-degree spin-polarized electron sources from strong-field multiphoton ionization.
我们对氙原子在圆偏振场中的多光子电离过程中动量和能量分辨的光电子自旋极化进行了实验和理论联合研究。我们分别用圆偏振近红外（800nm）和紫外（400nm）光实验测量了氙原子的光电子动量分布。我们通过将实验光电子动量分布与模拟结果进行比较来分析动量和能量分辨的光电子自旋极化，尽管我们不能仅从实验中得出自旋极化。我们表明，考虑到焦体积效应，使用 400nm 的圆偏振紫外光可以产生超过 90%的自旋极化，这使得通过动量选通来分离自旋态成为可能。这为从强场多光子电离中产生高极化度的自旋电子源铺平了道路。
