3-D Optical Interference Microscopy at the Lateral Resolution
3-D Optical Interference Microscopy at the Lateral Resolution
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DOI：
10.1080/15599612.2014.942924
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发表时间：
2014-10
影响因子：
5.5
通讯作者：
P. Lehmann;J. Niehues;S. Tereschenko
中科院分区：
文献类型：
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作者：
P. Lehmann;J. Niehues;S. Tereschenko
对于微米和纳米技术的应用，光学三维显微镜的横向分辨率成为一个日益重要的问题。然而，三维显微镜的横向分辨率很难用令人满意的方式定义。因此，我们首先研究了接近横向分辨率极限的高分辨率白光干涉显微镜的测量能力。测量和仿真结果表明，基于WLI信号的包络估计，似乎可以获得更好的横向分辨率。不幸的是，在接近横向分辨率极限的情况下，微结构的测量振幅出现了误差。另一方面，干涉相位估计的结果在这种情况下似乎是强低通滤波。此外，偏振对WLI仪器的传输特性和横向分辨率也有影响。TM偏振光对边缘绕射的敏感性较低，因此可以避免系统误差。然而，如果使用TE偏振光，除了由于条纹级数误差而产生的鬼步外，位相估计的结果似乎更接近真实的表面形貌。将WLI和结构照明显微镜相结合，可以进一步提高横向分辨率。由于接近横向分辨率极限的矩形轮廓的测量高度与实际高度相比通常太小，我们介绍了一种基于位相估计的方法，该方法能够正确地表征勉强横向分辨的矩形光栅的高度。
For applications in micro- and nanotechnologies the lateral resolution of optical 3-D microscopes becomes an issue of increasing relevance. However, lateral resolution of 3-D microscopes is hard to define in a satisfying way. Therefore, we first study the measurement capabilities of a highly resolving white-light interference (WLI) microscope close to the limit of lateral resolution. Results of measurements and simulations demonstrate that better lateral resolution seems to be achievable based on the envelope evaluation of a WLI signal. Unfortunately, close to the lateral resolution limit errors in the measured amplitude of micro-structures appear. On the other hand, results of interferometric phase evaluation seem to be strongly low-pass filtered in this case. Furthermore, the instrument transfer characteristics and the lateral resolution capabilities of WLI instruments are also affected by polarization. TM polarized light is less sensitive to edge diffraction and thus systematic errors can be avoided. However, apart from ghost steps due to fringe order errors, the results of phase evaluation seem to be closer to the real surface topography if TE polarized light is used. The lateral resolution can be further improved by combining WLI and structured illumination microscopy. Since the measured height of rectangular profiles close to the lateral resolution limit is generally too small compared to the real height, we introduce a method based on phase evaluation which characterizes the heights of barely laterally resolved rectangular gratings correctly.