Bo En, Chen Si, Cui Dongyao, Chen Shi, Yu Xiaojun, Luo Yuemei, Liu Linbo
Appl Opt. 2017 Jan 20;56(3):470-475. doi: 10.1364/AO.56.000470.
We developed spectral domain optical coherence tomography using a dual-channel spectrometer for complex conjugate artifacts (CCA) suppression. We used a three-line charge coupled device to simultaneously detect two interferometric spectra with 2π/3 phase difference. The complex interferometric signal was reconstructed by trigonometric manipulation of two real interferometric spectra, and then full-range images were obtained by use of inverse Fourier transform. Artifacts at direct current (DC) and the ghost remnant of the CCA are common issues with the previously reported two-spectrometer method because the slight mismatching between two spectral detection channels had strong negative effects on CCA suppression and appeared to be the limiting factor on system performance. This novel dual-channel spectrometer uses the same spectrometer optics for the two spectral detection channels and, therefore, achieves better matching between two spectral detection channels and consequently better performance in CCA suppression as compared with the dual spectrometer solution. Full-range imaging with CCA suppression up to ∼25 dB was demonstrated when imaging an attenuated reflector. The efficacy of both CCA and DC suppressions also was validated by imaging the anterior segment of a rat eye ex vivo. The quality of CCA-suppressed images was significantly improved with regard to those obtained with the dual-spectrometer design.
我们开发了一种使用双通道光谱仪抑制复共轭伪像（CCA）的光谱域光学相干断层扫描技术。我们使用三线电荷耦合器件同时检测具有2π/3相位差的两个干涉光谱。通过对两个实干涉光谱进行三角运算来重建复干涉信号，然后利用傅里叶逆变换获得全范围图像。直流（DC）处的伪像和CCA的重影残余是先前报道的双光谱仪方法常见的问题，因为两个光谱检测通道之间的轻微失配对CCA抑制有很强的负面影响，并且似乎是系统性能的限制因素。这种新型双通道光谱仪在两个光谱检测通道中使用相同的光谱仪光学元件，因此，与双光谱仪解决方案相比，两个光谱检测通道之间实现了更好的匹配，从而在CCA抑制方面具有更好的性能。在对衰减反射器成像时，展示了高达约25 dB的CCA抑制全范围成像。通过对离体大鼠眼前节成像，也验证了CCA和DC抑制的效果。与双光谱仪设计获得的图像相比，CCA抑制图像的质量得到了显著改善。
