A fundamental requirement for quantum technologies is the ability to coherently control the interaction between electrons and photons. However, in many scenarios involving the interaction between light and matter, the exchange of linear or angular momentum between electrons and photons is not feasible, a condition known as the dipole approximation limit. An example of a case beyond this limit that has remained experimentally elusive is when the interplay between chiral electrons and vortex light is considered, where the orbital angular momentum of light can be transferred to electrons. Here we present a mechanism for such an orbital angular momentum transfer from optical vortex beams to electronic quantum Hall states. Specifically, we identify a robust contribution to the radial photocurrent, in an annular graphene sample within the quantum Hall regime, that depends on the vorticity of light. This phenomenon can be interpreted as an optical pumping scheme, where the angular momentum of photons is transferred to electrons, generating a radial current, and the current direction is determined by the vorticity of the light. Our findings offer fundamental insights into the optical probing and manipulation of quantum coherence, with wide-ranging implications for advancing quantum coherent optoelectronics.

量子技术的一个基本要求是能够相干地控制电子和光子之间的相互作用。然而，在许多涉及光与物质相互作用的场景中，电子和光子之间的线性或角动量交换是不可行的，这种情况称为偶极子近似极限。超出此限制的一个例子在实验中仍然难以捉摸，当考虑手性电子和涡旋光之间的相互作用时，光的轨道角动量可以转移到电子。在这里，我们提出了一种从光学涡旋光束到电子量子霍尔态的这种轨道角动量转移的机制。具体来说，我们在量子霍尔状态内的环形石墨烯样品中确定了对径向光电流的稳健贡献，这取决于光的涡度。这种现象可以解释为光泵浦方案，其中光子的角动量转移到电子，产生径向电流，电流方向由光的涡度决定。我们的研究结果为量子相干的光学探测和操纵提供了基本见解，对推进量子相干光电子学具有广泛的意义。