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研制了扫频光学相干层析技术(SS-OCT)系统。该系统基于快速扫频激光光源,将轴向扫描频率由原来时域光学相干层析技术(OCT)系统的500 Hz提高到20 kHz。采用了基于OCT系统本身的预标定方法,实现了波数空间的线性校正。针对扫频光源光谱的非高斯型分布,对干涉光谱实施了基于窗口函数的光谱整形。对于干涉光谱中的直流项和自相关项,除了采用平衡探测共模抑制外,还运用了减除平均值的软件处理方法。系统纵向分辨率14μm,横向分辨率12 μm,在空气介质中的成像深度3.9 mm,利用研制的SS-OCT系统,成功实现了手指组织样品的快速OCT成像。
Developed swept-frequency optical coherence tomography (SS-OCT) system. The system is based on a fast sweep laser source that increases the axial sweep frequency from 500 Hz to 20 kHz from the original time-domain optical coherence tomography (OCT) system. The pre-calibration method based on OCT system is adopted to realize the linear correction of wavenumber space. Aiming at the non-Gaussian distribution of the spectrum of the sweep light source, a spectral shaping based on window function is implemented on the interference spectrum. For the DC terms and the autocorrelation terms in the interference spectrum, in addition to balanced detection of common mode rejection, a software-averaging method is also used. The longitudinal resolution of the system was 14μm, the lateral resolution was 12μm, and the imaging depth was 3.9 mm in the air medium. The rapid OCT imaging of finger tissue samples was successfully achieved with the developed SS-OCT system.