一种海绵状微结构的电磁增强效应.docVIP

 n Enhancement effects in Sponge-like shape microstructures# Wang Bin, Ma jiaju, Xu Xiaoxuan, Wang Yufang* (School of physics, Nankai University, Tianjin 300071) 5 10 15 20 25 30 35 Abstract: In this article we presents a sponge-like microstructure. By using the finite element method and finite difference time domain method, we establish the relationship between the enhancement and the size of the structure. And we provide an effective structure to achieve enhanced Raman spectroscopy to be applied in practice. Key words: Sponge-like shape; microstructures; SERS; Raman; Enhancement effects 0 Introduction The surface-enhanced Raman scattering (SERS) is one of the most intriguing discoveries in last century, and the search for an optimal structure which can achieve higher near-field optical enhancement at metal surface with SERS is still the focus of many researchers. Since theory has shown that this enhancement is associated with the excitation of surface plasmons, which always spatially localized in points with high curvature, so the surface of the structures are always designed to contain fractals with dimensions much smaller than the incident wavelength . Fractal is known as a geometric structure with self-similarity that is repeated at ever scales to produce complex shapes and surfaces. The fractal structure has no periodicity and no translational symmetry like crystal structures. Interaction of optical electromagnetic, and acoustical waves with fractal structures has been of theoretical and practical interest in recent years. With the restriction of fabrication, the surface of initial structures used in experiments were consist of randomly distributed fractals, named random fractals, such as a metal sputter-coated substrate and fractal clusters. Since natural power always leads staff to random, structures with random fractal surface are supported by many researchers. However, as the development of industry, structures with well-regulated fractal surface are