Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China.
Sci Rep. 2013;3:2402. doi: 10.1038/srep02402.
We demonstrate a novel detection scheme for the orbital angular momentum (OAM) of light using circular plasmonic lens. Owing to a division-of-amplitude interference phenomenon between the surface plasmon waves and directly transmitted light, specific intensity distributions are formed near the plasmonic lens surface under different OAM excitations. Due to different phase behaviors of the evanescent surface plasmon wave and the direct transmission, interference patterns rotate as the observation plane moves away from the lens surface. The rotation direction is a direct measure of the sign of OAM, while the amount of rotation is linked to the absolute value of the OAM. This OAM detection scheme is validated experimentally and numerically. Analytical expressions are derived to provide insights and explanations of this detection scheme. This work forms the basis for the realization of a compact and integrated OAM detection architect that may significantly benefit optical information processing with OAM states.
我们展示了一种使用圆形等离子体透镜检测光轨道角动量（OAM）的新方案。由于表面等离激元波与直接透射光之间的振幅分割干涉现象，在不同的 OAM 激发下，等离子体透镜表面附近会形成特定的强度分布。由于消逝的表面等离激元波和直接传输的相位行为不同，干涉图案会随着观察面远离透镜表面而旋转。旋转方向是 OAM 符号的直接度量，而旋转量与 OAM 的绝对值有关。该 OAM 检测方案已通过实验和数值进行了验证。推导了解析表达式，以提供对该检测方案的深入了解和解释。这项工作为实现紧凑、集成的 OAM 检测架构奠定了基础，这可能会极大地促进具有 OAM 态的光信息处理。
