PFI-TT: Metasurface-Optical Fiber Endoscopy Probe for Advanced Imaging

该创新-技术转化合作伙伴关系（PFI-TT）项目的更广泛影响/商业潜力源于内窥镜主动成像组件的尺寸大幅减小至小于200微米：一根人类头发的大小。大多数当前的内窥镜设计大于其目标身体区域，并且在成像开始之前必须被迫通过狭窄的通道。申报的Meta-Optical Fiber Endoscope（MOFE）器械占地面积小，允许显著降低侵入性治疗，降低并发症的可能性和手术期间的麻醉需求。MOFE平台还瞄准了其他尚未开发的生物医学成像市场，如心脏、脑深部和同步多功能成像。此外，这些全光纤结构提供了比当前设计更大的大规模和低成本制造的潜力。不需要组装许多单独的组件，可以在单个标准纳米纤维工艺中实现完整的MOFE探针，这代表每个器件的成本大幅降低。用于生产这些探针的方法也可以在平面化的光纤束上进行，从而允许并行制造数百或数千个器件。拟议项目将生产Meta-Optical Fiber Endoscope器械。通过使用平坦的光学超颖表面，即具有亚波长厚度的人造片材，不宽于光纤尖端本身，可以取代笨重的玻璃光学成像部件（透镜、反射镜、棱镜等）。具有由超薄纤维组分限定的装置纵横比。该项目将代表直接在光纤上制造的光学超颖表面与其他先进成像技术的首次统一，例如多模光纤中的波前整形，光学相干断层扫描和多功能脑成像，包括这些新设备的beta测试。该项目中使用的二氧化钛纳米圆柱超颖表面是高效的，即在可见光范围内超过90%的透射率，并且能够调谐透射相位以具有完全的波前控制。目前的原型将包括可控焦距的透镜，可调光束转向，偏振不敏感功能，甚至通过集成电可调材料同时结合上述任何功能的多功能。该项目将标志着高折射率可见超颖表面直接在光纤端面上的首次集成。该超表面的可调性将导致大视场成像，这是现有的内窥镜没有笨重的机械扫描仪无法实现的。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The broader impact/commercial potential of this Partnerships for Innovation - Technology Translation (PFI-TT) project stems from the drastic reduction in size of an endoscope’s active imaging component to less than 200 microns: the size of a single human hair. Most current endoscope designs are larger than their target body region and must be forced through a narrow passage before imaging begins. The small footprint of the proposed Meta-Optical Fiber Endoscope (MOFE) device allows significantly less invasive treatment, reducing the likelihood of complications and the need for anesthesia during the procedure. The MOFE platform also targets other untapped biomedical imaging markets, such as cardiac, deep brain, and simultaneous multi-functional imaging. Additionally, these all-on-fiber structures offer greater potential for large scale and low-cost fabrication than current designs. Rather than requiring the assembly of many individual components, a complete MOFE probe can be realized in a single standard nanofabrication process, representing a substantial reduction in cost per device. The method employed to produce these probes can also be performed on a planarized fiber bundle, allowing hundreds or thousands of devices to be made in parallel. The proposed project will produce Meta-Optical Fiber Endoscope devices. By using flat optical metasurfaces, i.e. artificial sheet materials with sub-wavelength thickness, no wider than the fiber tip itself, it is possible to replace bulky glass optical imaging components (lenses, mirrors, prisms, etc.) with a device aspect ratio defined by the ultra-thin fiber components. This project will represent the first unification of optical metasurfaces—fabricated directly on-fiber—with other advanced imaging techniques, such as wavefront shaping in multimode fiber, optical coherence tomography, and multifunctional brain imaging, including beta testing of these novel devices. The titanium dioxide nanocylinder metasurfaces used in this project are highly efficient, i.e. over 90% transmission in the visible range, and able to tune the transmitted phase to have full wavefront control. The current prototype will include lensing to a controllable focal length, tunable beam steering, polarization insensitive functionality, and even multifunctionality combining any of the above simultaneously by integrating electrically tunable materials. This project will mark the first integration of high-index visible metasurfaces directly on the fiber endface. The metasurface’s tunability will lead to large field of view imaging, which is not available in existing endoscopy without bulky mechanical scanners.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.