Numerical study of an apertureless near field scanning optical microscope probe under radial polarization illumination
Numerical study of an apertureless near field scanning optical microscope probe under radial polarization illumination
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DOI：
10.1364/oe.15.004106
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发表时间：
2007-04-02
期刊：
影响因子：
3.8
通讯作者：
Zhan, Qiwen
中科院分区：
文献类型：
--
作者：
Chen, Weibin;Zhan, Qiwen
采用轴对称三维有限元模型研究了银涂层玻璃针尖附近的电磁场分布。在径向偏振照明下，由于在空气/银界面上传播的表面等离子体激元的相长干涉，在针尖的顶点处发现了一个强烈增强的场。系统地分析了增强因子和表面等离子体共振激发。通过对不同尖端锥角和照明几何形状的探索，研究了场增强的最佳条件。数值计算结果表明，在632.8nm光激发下，可以获得半高宽为10 nm的局域电磁场. (c)2007年，美国光学学会。
An axially symmetric three-dimensional finite element method model is applied to investigate the electromagnetic field distribution in the vicinity of a silver coated glass tip. Under radially polarized illumination, a strongly enhanced field located at the apex of the tip is found due to the constructive interference of surface plasmon propagating at the air/silver interface. The enhancement factor and surface plasmon resonance excitation are analyzed systematically. The optimal condition for field enhancement is investigated through the exploration of different taper angles of the tip and the illumination geometry. The numerical studies show that a significantly enhanced localized electromagnetic field with a full-width- half-maximum of 10 nm is obtainable with 632.8 nm optical excitation. (c) 2007 Optical Society of America.