Albar Esra Ilke, Bonafé Franco P, Kosheleva Valeriia P, Ohlmann Sebastian T, Appel Heiko, Rubio Angel
Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761, Hamburg, Germany.
Max Planck Computing and Data Facility, Gießenbachstr. 2, 85748, Garching, Germany.
Sci Rep. 2023 Sep 7;13(1):14748. doi: 10.1038/s41598-023-41606-3.
The microscopic mechanism of the light-matter interactions that induce orbital angular momentum (OAM) in electromagnetic fields is not thoroughly understood. In this work, we employ Archimedean spiral vortex generators in time-resolved numerical simulations using the Octopus code to observe the behind-the-scenes of OAM generation. We send a perfect circularly-polarized plane-wave light onto plasmonic optical vortex generators and observe the resulting twisted light formation with complete spatio-temporal information. In agreement with previous works, we find that emission from the plasmonic spiral branches shapes the vortex-like structure and governs the OAM generation in the outgoing electromagnetic field. To characterize the generated beam further, we emulate the emission from vortex generators with current emitters preserving the spiral geometry. We subject a point-particle system to the generated field and record the orbital angular momentum transfer between the electromagnetic field and the point particle. Finally, we probe the OAM density locally by studying the induced classical trajectory of point particles, which provides further insight into the spatio-temporal features of the induced OAM.
诱导电磁场中轨道角动量（OAM）的光与物质相互作用的微观机制尚未得到充分理解。在这项工作中，我们在使用Octopus代码进行的时间分辨数值模拟中采用阿基米德螺旋涡旋发生器，以观察OAM产生的幕后情况。我们将完美圆偏振平面波光照射到等离子体光学涡旋发生器上，并观察由此产生的具有完整时空信息的扭曲光形成。与先前的工作一致，我们发现等离子体螺旋分支的发射塑造了涡旋状结构，并控制了出射电磁场中的OAM产生。为了进一步表征所产生的光束，我们用保持螺旋几何形状的电流发射器模拟涡旋发生器的发射。我们将一个点粒子系统置于所产生的场中，并记录电磁场与点粒子之间的轨道角动量转移。最后，我们通过研究点粒子的诱导经典轨迹来局部探测OAM密度，这为诱导OAM的时空特征提供了进一步的见解。
