Multiple light scattering in biomedical tissue limits the penetration depth of optical imaging systems such as optical coherence tomography. To increase the imaging depth in scattering media, a computational method based on coherent reflection matrix measurement has been developed using low coherence interferometry. The complex reflection matrix is obtained via point-by-point scanning followed by a phase-shifting method; then singular value decomposition is used to retrieve the singly back-scattered light. However, the in vivo application of the current reported method is limited due to the slow acquisition speed of the matrix. In this Letter, a wide-field heterodyne-detection method is adopted to speed up the complex matrix measurement at a deep tissue layer. Compared to the phase-shifting method, the heterodyne-detection scheme retrieves depth-resolved complex amplitudes faster and is more stable without mechanical movement of the reference mirror. As a result, the matrix measurement speed is increased by more than one order of magnitude.

中文翻译：

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基于广域外差检测对反射矩阵的快速测量，扩展了面部光学相干断层扫描的成像深度。

生物医学组织中的多次光散射限制了光学成像系统（如光学相干断层扫描）的穿透深度。为了增加散射介质中的成像深度，已经开发了使用低相干干涉术的基于相干反射矩阵测量的计算方法。复数反射矩阵是通过逐点扫描然后相移的方法获得的；然后使用奇异值分解来获取单个后向散射光。然而，由于基质的缓慢采集速度，当前报道的方法的体内应用受到限制。在这封信中，采用了广域外差检测方法来加快在深层组织层的复杂矩阵测量。与相移法相比 外差检测方案可以更快地检索深度解析的复振幅，并且在没有参考镜的机械移动的情况下更加稳定。结果，矩阵测量速度提高了一个数量级以上。