Nondestructive Measurement of Orbital Angular Momentum for an Electron Beam.
Nondestructive Measurement of Orbital Angular Momentum for an Electron Beam.
复制标题
电子束轨道角动量的无损测量。
DOI：
10.1103/physrevlett.117.154801
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发表时间：
2016
影响因子：
8.6
通讯作者：
E. Karimi
中科院分区：
文献类型：
--
作者：
H. Larocque;F. Bouchard;V. Grillo;Alicia Sit;S. Frabboni;R. Dunin‐Borkowski;M. Padgett;R. Boyd;E. Karimi
具有螺旋形相位前沿的自由电子（称为“扭曲”电子）具有轨道角动量（OAM），并且因此具有沿其传播方向的量子化磁偶极矩沿着。这种内禀磁矩可用于探测材料特性。因此，扭曲电子在材料科学中有许多潜在的应用。测量这个量通常依赖于一系列投影测量，这些测量随后改变了电子携带的OAM。在这封信中，我们提出了一种非破坏性的方法来测量电子束的OAM通过这种相关的磁偶极子与导电环的相互作用。这样的相互作用导致在回路内产生感应电流，其被发现与电子的OAM值成正比。此外，电子在测量时没有经历OAM变化并且仅经历最小的能量损失，并且因此所提出的技术具有非破坏性。
Free electrons with a helical phase front, referred to as "twisted" electrons, possess an orbital angular momentum (OAM) and, hence, a quantized magnetic dipole moment along their propagation direction. This intrinsic magnetic moment can be used to probe material properties. Twisted electrons thus have numerous potential applications in materials science. Measuring this quantity often relies on a series of projective measurements that subsequently change the OAM carried by the electrons. In this Letter, we propose a nondestructive way of measuring an electron beam's OAM through the interaction of this associated magnetic dipole with a conductive loop. Such an interaction results in the generation of induced currents within the loop, which are found to be directly proportional to the electron's OAM value. Moreover, the electron experiences no OAM variations and only minimal energy losses upon the measurement, and, hence, the nondestructive nature of the proposed technique.