Kou E F, Tamir T
Appl Opt. 1989 Mar 15;28(6):1169-77. doi: 10.1364/AO.28.001169.
The field properties of surface plasmons produced by realistically bounded beams incident in various attenuated total reflection (ATR) geometries are examined. Analytical results are first derived for the general case dealing with a beam field incident in a multilayered configuration. We show that, at the phase matching condition, the reflected field can be severely distorted in comparison with the incident beam shape. We also find that the power intensity inside the metal medium can be much smaller than that expected under the assumption of plane wave incidence. However, when the beamwidth is larger than the proportion range of the excited plasmon, the power intensity profiles and find that they exhibit distinguishing characteristics. In particular, for an incident Gaussian beam, the location of maximum power density on the metal surface shifts with respect to the center of the incident beam by a distance of the order of the plasmon propagation length. For a rectangular beam incident at the phase matching condition, on the other hand, the propagation range of the coupled surface plasmon can be found directly from the profile of the reflected field. We also show the overall process of beam wave coupling in the ATR geometry can be simulated by a spatial operating system having the response of either a differentiator (for the reflected field) or an integrator (for the transmitted field).
研究了在各种衰减全反射（ATR）几何结构中，由实际受限光束入射产生的表面等离子体激元的场特性。首先针对处理多层配置中光束场入射的一般情况推导了解析结果。我们表明，在相位匹配条件下，与入射光束形状相比，反射场可能会严重失真。我们还发现，金属介质内部的功率强度可能比平面波入射假设下预期的要小得多。然而，当光束宽度大于激发等离子体激元的比例范围时，功率强度分布呈现出显著特征。特别是，对于入射高斯光束，金属表面最大功率密度的位置相对于入射光束中心移动了等离子体激元传播长度量级的距离。另一方面，对于在相位匹配条件下入射的矩形光束，耦合表面等离子体激元的传播范围可以直接从反射场的分布中找到。我们还表明，ATR几何结构中的光束波耦合的整个过程可以由具有微分器（用于反射场）或积分器（用于透射场）响应的空间操作系统来模拟。
