基于频域分析的光学相干显微镜中的色散补偿

提出基于频域分析的色散补偿方法,对光学相干显微镜的干涉信号进行快速傅里叶变换,得到频率幅值极大值对应的平均波数,将提取的解包裹后的相位以平均波数为中心做多项式拟合,得到二阶色散系数。实验中,通过在参考臂中插入不同厚度的色散介质来引入两个干涉臂色散介质的光程差,并求得相应的二阶色散系数。通过最小二乘线性拟合,证实了二阶色散系数和色散介质的相对厚度具有很好的线性关系。根据该线性关系,可以在参考臂中插入适当厚度的色散介质来完全补偿干涉系统的二阶色散。

Dispersion Compensation Based on Frequency Domain Analysis in Optical Coherence Microscopy

The dispersion compensation method based on frequency domain analysis (FDA) is proposed. The interference signal acquired from the optical coherence microscopy (OCM) is Fourier transformed to the frequency domain and the mean wavenumber corresponding to the peak frequency amplitude is obtained. A polynomial is fit to the unwrapped phase centered on the mean wavenumber in order to estimate the coefficient of the second order dispersion. In the experiment, dispersive elements with different thicknesses are inserted into the reference arm to calculate the second order dispersion coefficients corresponding to the optical path differences (OPDs) of the dispersive elements of two interference arms. A linear least squares fit demonstrates the good linearity between the second order dispersion coefficient and the relative thickness of the dispersive elements. In accordance with this linearity, a dispersive element with the appropriate thickness inserted into the reference arm will compensate the second order dispersion of the interference system.