Multiple scattering in biomedical tissue limits the imaging depth within a range of 1-2 mm for conventional optical imaging techniques. To extend the imaging depth into the scattering medium, a computational method based on the reflection matrix measurement has been developed to retrieve the singly back-scattered signal light from the dominant detrimental multiple-scattered background. After applying singular value decomposition on the measured matrix in the post-process, the target image underneath the turbid media is clearly recovered. To increase the depth of focus of the incident light by elongating the focal spot along the optical axis, a digital grating pattern is specially designed and displayed on a phase-only spatial light modulator to generate the Bessel-like beam for lateral point scanning. According to the results, the depth of focus is increased up to 2.4 mm which is much longer than the value of ∼50 μm obtained by using the conventional focused Gaussian beam, leading to a deeper penetration depth due to the self-healing feature of the Bessel-like beam. In addition, generation of the Bessel-like beam simplifies the axial scanning process by getting rid of the need to mechanically translate the focal zone along the optical axis of an objective with a high numerical aperture. By combining this method with an optical coherence tomography system with a low coherence light source, a depth-resolved optical image is obtained underneath a highly turbid medium.

中文翻译：

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通过将反射矩阵测量与基于类贝塞尔光束的光学相干断层扫描相结合，在高散射介质中进行深度成像

生物医学组织中的多重散射将常规光学成像技术的成像深度限制在 1-2 毫米范围内。为了将成像深度扩展到散射介质中，已经开发了一种基于反射矩阵测量的计算方法，以从主要的有害多重散射背景中检索单一背向散射信号光。在后处理中对测量矩阵应用奇异值分解后，混浊介质下方的目标图像清晰地恢复。为了通过沿光轴拉长焦斑来增加入射光的焦深，专门设计了数字光栅图案并显示在仅相位空间光调制器上，以产生用于横向点扫描的类贝塞尔光束。根据结果​​，焦深增加到 2.4 mm，远大于使用传统聚焦高斯光束获得的 ~50 μm 值，由于类贝塞尔光束的自愈特性，导致更深的穿透深度。此外，类贝塞尔光束的产生无需沿具有高数值孔径的物镜的光轴机械平移焦区，从而简化了轴向扫描过程。通过将此方法与具有低相干光源的光学相干断层扫描系统相结合，在高度混浊的介质下方获得深度分辨的光学图像。由于类贝塞尔光束的自愈特性，导致更深的穿透深度。此外，类贝塞尔光束的产生无需沿具有高数值孔径的物镜的光轴机械平移焦区，从而简化了轴向扫描过程。通过将此方法与具有低相干光源的光学相干断层扫描系统相结合，在高度混浊的介质下方获得深度分辨的光学图像。由于类贝塞尔光束的自愈特性，导致更深的穿透深度。此外，类贝塞尔光束的产生无需沿具有高数值孔径的物镜的光轴机械平移焦区，从而简化了轴向扫描过程。通过将此方法与具有低相干光源的光学相干断层扫描系统相结合，在高度混浊的介质下方获得深度分辨的光学图像。