An improved three-beam Doppler optical coherence tomography system was developed. It utilizes a custom-made three-facet prism telescope to improve the transversal resolution at the sample. Furthermore, a two-axis gimbal-less MEMS mirror is used to minimize off-pivot beam movement at the pupil of the eye, enabling circular scanning for in vivo retinal measurements. We demonstrate the system’s abilities for in vitro circular scanning to measure absolute flow and to reconstruct the full velocity vector on a bifurcation flow phantom. Moreover, in vivo retinal measurements using circular scanning around vessel bifurcations of healthy human volunteers were performed. Measurements of the absolute mean flow and its orientation are in good agreement with the expected values for in vitro measurements. For in vivo measurements, the in- and outflow of blood for retinal vessel bifurcations show an excellent agreement, demonstrating the reliability of the technique.

中文翻译：

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使用小棱镜望远镜和 MEMS 反射镜的三光束多普勒光学相干断层扫描以提高横向分辨率

研制了一种改进的三束多普勒光学相干断层扫描系统。它利用定制的三棱镜望远镜来提高样品的横向分辨率。此外，使用双轴无万向节 MEMS 反射镜可最大限度地减少眼睛瞳孔处的离轴光束移动，从而实现体内视网膜测量的圆形扫描。我们展示了该系统的体外循环扫描能力，以测量绝对流量并重建分叉流模型上的全速度矢量。此外，使用围绕健康人类志愿者的血管分叉处的圆形扫描进行体内视网膜测量。绝对平均流量及其方向的测量值与体外测量的预期值非常吻合。对于体内测量，