Interference signals in coherence scanning interferometry at high numerical apertures and narrow bandwidth illumination are spectrally broadened. This enables phase analysis within a spectral range much wider than the spectral distribution of the light emitted by the light source. Consequently, different surface features can be resolved depending on the wavelength used for phase analysis of the interference signals. In addition, the surface topography itself affects the spectral composition of interference signals in different ways. Signals related to tilted surfaces or step height structures show special spectral characteristics. Thus, spectral amplitude and phase analysis enables a better understanding of the underlying physical mechanisms and gives hints how to improve the measurement accuracy.

中文翻译：

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高数值孔径下低相干干涉图的光谱成分

相干扫描干涉术中在高数值孔径和窄带宽照明下的干扰信号在光谱上得到了加宽。这使得能够在比光源发出的光的光谱分布宽得多的光谱范围内进行相位分析。因此，取决于用于干扰信号的相位分析的波长，可以分辨出不同的表面特征。此外，表面形貌本身以不同的方式影响干扰信号的频谱组成。与倾斜表面或台阶高度结构有关的信号显示特殊的频谱特性。因此，频谱幅度和相位分析可以更好地理解潜在的物理机制，并提示如何提高测量精度。