Superweak momentum transfer near optical vortices
Superweak momentum transfer near optical vortices
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DOI：
10.1088/2040-8978/15/12/125701
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发表时间：
2013-12
影响因子：
2.1
通讯作者：
S. Barnett;M. Berry
中科院分区：
文献类型：
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作者：
S. Barnett;M. Berry
在单色光束中的涡旋附近，局部波矢量（相位梯度）的长度可以超过代表光束的叠加中的任何平面波的波数。检测这些“超弱”动量的一种方法是通过吸收光束中的单个大动量光子，向位于涡旋附近的小粒子施加“超级冲击”。该过程的模型是具有与光束共振的跃迁的二能级原子。半经典分析表明，原子的动量分布通过与涡旋光束的相互作用而发生变化，其变化量几乎可以达到目标超级冲击，并且通常大于构成光束的平面波中的动量。
Near a vortex in a monochromatic light beam, the length of the local wavevector (phase gradient) can exceed the wavenumber in any of the plane waves in the superposition representing the beam. One way to detect these ‘superweak’ momenta could be by ‘superkicks’ imparted to a small particle located near the vortex, by absorbing individual large-momentum photons from the beam. A model for this process is a two-level atom with a transition resonant with the light beam. A semiclassical analysis shows that the momentum distribution of the atom is shifted by interaction with the vortex beam, by amounts that can almost reach the target superkicks and are usually greater than the momenta in the plane waves comprising the beam.