Raghunathan S B, Gan C H, van Dijk T, Ea Kim B, Schouten H F, Ubachs W, Lalanne P, Visser T D
Dept. of Electrical Engineering, Delft University of Technology, Delft, The Netherlands.
Opt Express. 2012 Jul 2;20(14):15326-35. doi: 10.1364/OE.20.015326.
We report a plasmon steering method that enables us to dynamically control the direction of surface plasmons generated by a two-mode slit in a thin metal film. By varying the phase between different coherent beams that are incident on the slit, individual waveguide modes are excited. Different linear combinations of the two modes lead to different diffracted fields at the exit of the slit. As a result, the direction in which surface plasmons are launched can be controlled. Experiments confirm that it is possible to distribute an approximately constant surface plasmon intensity in any desired proportion over the two launching directions. We also find that the anti-symmetric mode generates surface plasmons more efficiently than the fundamental symmetric mode.
我们报道了一种等离子体操控方法，该方法使我们能够动态控制由薄金属膜中的双模狭缝产生的表面等离子体的方向。通过改变入射到狭缝上的不同相干光束之间的相位，激发了各个波导模式。这两种模式的不同线性组合会在狭缝出口处产生不同的衍射场。结果，可以控制表面等离子体的发射方向。实验证实，有可能以任何期望的比例在两个发射方向上分布近似恒定的表面等离子体强度。我们还发现，反对称模式比基本对称模式更有效地产生表面等离子体。
