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

这一创新技术转化伙伴关系(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大小大幅减少到200微米以下：一根头发的大小。大多数目前的内窥镜设计都大于其目标身体区域，在成像开始之前必须强制通过狭窄的通道。拟议的亚光纤内窥镜(MOFE)设备占地面积小，可以显著减少侵入性治疗，减少并发症的可能性和在手术过程中对麻醉的需求。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，这些全光纤结构比目前的设计提供了更大的大规模和低成本制造的潜力。一个完整的MoFe探头可以在一个标准的纳米加工过程中实现，而不是需要组装许多单独的组件，这意味着每个设备的成本大幅降低。用来制造这些探头的方法也可以在平坦化的光纤束上进行，从而允许并行制造数百或数千个设备。拟议的项目将生产元光纤内窥镜设备。通过使用不比光纤尖端本身宽的平坦光学介面，即具有亚波长厚度的人造薄片材料，可以取代笨重的玻璃光学成像部件(透镜、反射镜、棱镜等)。具有由超薄光纤组件定义的器件纵横比。该项目将代表着直接在光纤上制造的光学超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、光学相干层析成像和多功能脑成像，包括这些新设备的贝塔测试。本项目中使用的二氧化钛纳米柱面具有很高的效率，即在可见光范围内透过率超过90%，并能够调节透射位相以实现全波前控制。目前的原型将包括透镜到可控制的焦距，可调的光束控制，偏振不敏感的功能，甚至通过集成电子可调材料同时结合以上任何一项的多功能。该项目将标志着首次将高折射率可见准表面直接集成在光纤端面上。MetasSurface的可调性将导致大视野成像，这在没有笨重机械扫描仪的现有内窥镜检查中是不可用的。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.