Wang Kai, Ding Zhihua, Zeng Yan, Meng Jie, Chen Minghui
State Key Lab of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, PR China.
Opt Express. 2009 Sep 14;17(19):16820-33. doi: 10.1364/OE.17.016820.
A high speed spectral domain optical coherence tomography based on the spatial sinusoidal phase modulation for the elimination of complex-conjugate artifact is presented, where sinusoidal phase modulation of reference arm (M scan) and transverse scanning of sample arm (B scan) are performed simultaneously (sinusoidal B-M method). Herein, the linear phase modulation of the reference arm in conventional linear B-M method is modified to sinusoidal phase modulation. The proposed sinusoidal B-M method relaxes the requirements on the phase-shifting mechanical system and avoids sensitivity fall-off along the transverse direction in contrast to the linear B-M method. A criterion for the relation between transverse over-sampling factor and modulation frequency for optimal complex conjugate rejection is deduced and verified by experiments. Under this criterion, the complex spectral interferogram is reconstructed by harmonic analysis and digital synchronous demodulation. Double imaging depth range on fresh shrimp at A-scan rate of 10 kHz with complex conjugate rejection ratio up to 45 dB is achieved.
提出了一种基于空间正弦相位调制以消除复共轭伪像的高速光谱域光学相干断层扫描方法，其中参考臂的正弦相位调制（M扫描）和样品臂的横向扫描（B扫描）同时进行（正弦B-M方法）。在此，将传统线性B-M方法中参考臂的线性相位调制修改为正弦相位调制。与线性B-M方法相比，所提出的正弦B-M方法放宽了对相移机械系统的要求，并避免了沿横向方向的灵敏度下降。推导了横向过采样因子与调制频率之间关系的准则，以实现最佳复共轭抑制，并通过实验进行了验证。在此准则下，通过谐波分析和数字同步解调重建复谱干涉图。在10 kHz的A扫描速率下，对鲜虾实现了双成像深度范围，复共轭抑制比高达45 dB。
