Yin Biwei, Dwelle Jordan, Wang Bingqing, Wang Tianyi, Feldman Marc D, Rylander Henry G, Milner Thomas E
J Opt Soc Am A Opt Image Sci Vis. 2015 Nov 1;32(11):2169-77. doi: 10.1364/JOSAA.32.002169.
Optical coherence tomography (OCT) is an imaging technique that constructs a depth-resolved image by measuring the optical path-length difference between broadband light backscattered from a sample and a reference surface. For many OCT sample arm optical configurations, sample illumination and backscattered light detection share a common path. When a phase mask is placed in the sample path, features in the detected signal are observed, which suggests that an analysis of a generic common path OCT imaging system is warranted. In this study, we present a Fourier optics analysis using a Fresnel diffraction approximation of an OCT system with a path-length-multiplexing element (PME) inserted in the sample arm optics. The analysis may be generalized for most phase-mask-based OCT systems. A radial-angle-diverse PME is analyzed in detail, and the point spread function, coherent transfer function, sensitivity of backscattering angular diversity detection, and signal formation in terms of sample spatial frequency are simulated and discussed. The analysis reveals important imaging features and application limitations of OCT imaging systems with a phase mask in the sample path optics.
光学相干断层扫描（OCT）是一种成像技术，它通过测量从样品背向散射的宽带光与参考表面之间的光程差来构建深度分辨图像。对于许多OCT样品臂光学配置，样品照明和背向散射光检测共享一条公共路径。当在样品路径中放置一个相位掩模时，在检测到的信号中会观察到一些特征，这表明对通用的共光路OCT成像系统进行分析是有必要的。在本研究中，我们使用在样品臂光学系统中插入了光程复用元件（PME）的OCT系统的菲涅耳衍射近似进行傅里叶光学分析。该分析可推广到大多数基于相位掩模的OCT系统。详细分析了一种径向角多样的PME，并对其点扩散函数、相干传递函数、背向散射角分集检测的灵敏度以及基于样品空间频率的信号形成进行了模拟和讨论。该分析揭示了在样品路径光学系统中带有相位掩模的OCT成像系统的重要成像特征和应用局限性。
