Higher-order Bessel-like optical beams can be created through off-axis coupling of light into a multimode fiber. Thanks to the aberration that is inherent in spherical surfaces, through directing the Bessel-like beam comprising multiple concentric rings onto a low-cost lens, we created multiple foci at different depths. Moreover, scanning of the optical fiber with a piezoelectric actuator in the lateral direction, we were able to acquire data from different targets located at different planes. After coupling back into the fiber, the reflected portions of light from different targets could be spatially differentiated and directed to different photo-detection units. The proposed architecture is particularly appealing for laser scanning endoscopy applications, as it does not require additional passive or active optical components for generating Bessel beams (axicons or spatial light modulators), therefore offering both miniaturized realization and high optical transmission. We’ve further demonstrated the tunability of foci separation via altering fiber-coupling conditions with tilt and translation stages. Overall, the proposed scanning method has paved the way for addressing multiple slices at single lateral scan, thus offering improved speed for imaging or ablation applications.

中文翻译：

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使用高阶贝塞尔光束和球面透镜对多个切片进行同步成像

通过将光离轴耦合到多模光纤中，可以产生类似贝塞尔的高阶光束。由于球面固有的像差，通过将包含多个同心环的类贝塞尔光束引导到低成本透镜上，我们在不同深度创建了多个焦点。此外，通过横向压电致动器扫描光纤，我们能够从位于不同平面的不同目标获取数据。耦合回光纤后，来自不同目标的光的反射部分可以在空间上区分并引导到不同的光电检测单元。所提出的架构对激光扫描内窥镜应用特别有吸引力，因为它不需要额外的无源或有源光学组件来产生贝塞尔光束（轴棱镜或空间光调制器），因此提供小型化实现和高光传输。我们通过倾斜和平移阶段改变光纤耦合条件，进一步证明了焦点分离的可调谐性。总体而言，所提出的扫描方法为在单横向扫描中处理多个切片铺平了道路，从而为成像或消融应用提供了更高的速度。