Atomic spectroscopy with twisted photons: Separation of M1−E2 mixed multipoles
Atomic spectroscopy with twisted photons: Separation of M1−E2 mixed multipoles
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DOI：
10.1103/physreva.97.023422
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发表时间：
2018-01
影响因子：
2.9
通讯作者：
A. Afanasev;C. Carlson;M. Solyanik
中科院分区：
文献类型：
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作者：
A. Afanasev;C. Carlson;M. Solyanik
我们分析了扭曲光子或沿沿着传播方向携带额外轨道角动量的光子对原子的光激发。从角动量和宇称的考虑，我们能够扭转光子光激发振幅与它们的平面波类似物，独立的原子波函数的细节。我们分析了电离原子混合多极E2-M1跃迁的光吸收截面，发现了光子拓扑结构的根本差异。我们的理论分析表明，它是可能的，以提取不同的多极贡献的相对跃迁率作为原子的位置（或碰撞参数）相对于光学涡旋中心的函数，通过测量的光激发率。所提出的多极子分离技术可以实现，如果目标的原子位置是解决与亚波长精度，例如，与保罗陷阱。数值例子硼类高电荷态离子（HCI）。
We analyze atomic photoexcitation into the discrete states by twisted photons, or photons carrying extra orbital angular momentum along their direction of propagation. From the angular momentum and parity considerations, we are able to relate twisted-photon photoexcitation amplitudes to their plane-wave analogues, independently of the details of the atomic wave functions. We analyzed the photo-absorption cross sections of mixed-multipolarity $E2-M1$ transitions in ionized atoms and found fundamental differences coming from the photon topology. Our theoretical analysis demonstrates that it is possible to extract the relative transition rates of different multipolar contributions by measuring the photo-excitation rate as a function of the atom's position (or the impact parameter) with respect to the optical vortex center. The proposed technique for separation of multipoles can be implemented if the target's atom position is resolved with sub-wavelength accuracy, for example, with Paul traps. Numerical examples are presented for Boron-like highly-charged ions (HCI).