Department of Experimental Physics, Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany.
ACS Appl Mater Interfaces. 2013 Jul 10;5(13):6009-16. doi: 10.1021/am400712r. Epub 2013 Jun 5.
We discuss the controlled subdiffraction modulations of photosensitive polymer films that are induced by surface plasmon interference in striking contrast to well-known conventional microscopic gratings. The near-field light intensity patterns were generated at the nanoslits fabricated in a silver layer with the photosensitive polymer film placed above. We observed that the topographical modulations can be excited only when the polarization is perpendicular to the nanoslits. Moreover, we have shown that light with certain wavelengths resulted in a characteristic topographical pattern with the periodicity three times smaller than the wavelength of incoming light. A combination of experimental observations with simulations showed that the unique subdiffraction topographical patterns are caused by constructive interference between two counter-propagating surface plasmon waves generated at neighboring nanoslits in the metal layer beneath the photosensitive polymer film. The light intensity distribution was simulated to demonstrate strong dependency upon the slit array periodicity as well as wavelength and polarization of incoming light.
我们讨论了由表面等离激元干涉引起的光致聚合物薄膜的亚衍射控制调制，这与众所周知的常规微观光栅形成鲜明对比。近场光强模式是在银层中的纳米狭缝中产生的，在银层上放置了光致聚合物薄膜。我们观察到，只有当偏振方向垂直于纳米狭缝时，才能激发形貌调制。此外，我们已经表明，某些波长的光会产生具有周期性的特征形貌图案，其周期性比入射光的波长小三倍。实验观察与模拟的结合表明，独特的亚衍射形貌图案是由光致聚合物薄膜下方金属层中相邻纳米狭缝中产生的两个反向传播的表面等离激元波之间的相长干涉引起的。模拟了光强分布，以证明其对狭缝阵列周期性以及入射光的波长和偏振的强烈依赖性。
