【作者】 唐麟； 谢建平； 顾春； 王沛； 鲁拥华；

【Author】 TANG Lin, XIE Jianping, Gu Chun, LU Yonghua, WANG Pei Department of Physics, University of Science and Technology of china, 230026

【机构】 中国科学技术大学物理系；

【摘要】 我们用边界波衍射理论对无孔SNOM探针针尖的近场衍射进行了分析,得出在不同偏振光入射情况下,探针针尖的近场衍射场分布。在圆形的衍射图样中,平行于入射光电矢量的方向上的衍射光场强度分布为中间部分凹陷,在靠近针尖几何结构边沿投影处附近出现尖峰结构,而垂直于入射光电矢量的方向上的衍射光场强度分布则在中央出现极大值,远离中央,光强逐渐减小,没有和针尖几何结构明显的对应关系。分析表明这是因为P分量的线偏光比S分量的有着更高的分辨率的原故。由此提出了采用电矢量仅在径向偏振的光作为入射光场,模拟结果显示这样可以在二维平面上得到更高的分辨率。更多还原

【Abstract】 The near-field diffraction of the tip of apertureless scanning near-field optical microscopy is analyzed by boundary diffraction method and the relation between the polarization of the incident light and the near-field diffraction patterns of the tip is investigated. In the circular diffraction patterns of the tip, there are two sharp peaks near the edge of the tip’s geometrical projection in the direction of the incident ligth’s electricfield vector, but the intensity is gradual attenuation far away from the middle in the other direction without any obvious relation to the size of the tip. This means the P polarized component has higher resolution than the S polarized component. From these results, the incident circular light beam with electric field only polarized in the radial is introduced. The diffraction patterns of this new incident circle light beam shows it has higher resolution in the 2D plane than linearly or circular polarized beam.更多还原