近场光学中成象衬度机制的研究

本文从理论上研究了收集式近场光学显微镜中的成角衬度问题。采用三维时域有限差分法计算了光学近场区域亚波长尺度的电磁场分布。计算表明；利用ｐ偏振光成象可以得到样品的形貌衬度，而利用ｓ偏振光成象可以得到样品形貌的边缘象。该结果为近场光学显同镜中的图像解释及新仪器的开发提供了理论依据。

Study on the contrast mechanisms in collection-mode scanning near-field optical microscope

In this paper,we study theoretically and numerically the contrast mechanism in collection mode scanning near field optical microscope (SNOM).The distributions of electromagnetic fields in the optical near field of the sample are computed by using a finite difference time domain method.Our results show that both signals generated by two kinds of polarization of light can be used, p polarization for topography and s for the edged checkout of different physical feature of the sample.These may be useful for the interpretation of the images in SNOM and the development of the new SNOM instruments.