Pixel-level 3D nanophotonic structures for multi-modality image sensors

消费者相机通常捕获场景的二维（2D）图像，或记录电影。专用光学成像设备还可以捕获额外的信息，例如光的偏振，甚至场景中物体的三维（3D）图像。这种额外的信息在广泛的应用中是有帮助的，例如在自动驾驶汽车的传感器中，用于在生物医学成像中识别不同类型的细胞和组织，或者用于保持比简单的2D图像提供的更丰富的历史记录。虽然已经存在可以记录3D和偏振信息的设备，但它们通常比标准手机相机更大、更笨重。在该提案中，将研究显著减小此类装置的尺寸和重量的方法。这不仅涉及新的光学设计，还涉及用比光波长小得多的积木设计和构建3D光学设备的新方法。除了实现特别小的设备之外，这种小的构建块基于与应用于大型光学器件的物理原理不同的物理原理与光相互作用。这项研究将被纳入亚利桑那大学的一门课程，本科生和高中教师也将参与这项研究。美国原住民学生和他们的教育工作者，他们往往是在他们接触科学和工程方面处于不利地位，将是一个主要的人口统计目标。技术：本提案的目标是使用三维（3D）纳米光子学，使成像设备的角度，波长和偏振灵敏度在显着更紧凑和更轻的重量系统比目前可能的。在现有的角度敏感的3D光场成像方法中，衍射极限强加了最小有用像素尺寸。虽然之前没有证明，但纳米光子学提供了显着降低最小像素尺寸的潜力，这反过来又可以减少任何外部光学器件的尺寸。新型的基于高速优化的算法将用于设计由金属和/或介电纳米颗粒构建块组成的3D纳米光子结构。在各个像素上，不同的结构将选择性地接收具有特定入射角、偏振和/或波长的入射光。覆盖整个像素块的光子纳米结构也将被设计成基于入射角、波长和偏振对入射光进行分类。纳米结构将使用基于光学镊子的快速原型制作方法制造。胶体纳米颗粒结构单元将被化学官能化以在使用光镊彼此接触时结合。在图像传感器上制造纳米光子结构之后，它们将在控制良好的照明条件下使用单色激光源以特定的偏振方向以特定的角度进行测试，以及在日常宽带，宽场场景中进行测试。一个紧凑和重量轻的多模态成像设备将被创建。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Consumer cameras typically capture a two-dimensional (2D) image of a scene, or record a movie. Specialized optical imaging devices can also capture additional information such as the polarization of the light or even a three-dimensional (3D) image of objects in a scene. This extra information is helpful in a wide range of applications, such as in sensors for self-driving cars, for identifying different types of cells and tissues in biomedical imaging, or for keeping a richer historical record than is offered by a simple 2D image. While devices already exist that can record 3D and polarization information, they are typically much larger and bulkier than a standard cell phone camera. In this proposal, approaches to significantly reduce the size and weight of such devices will be studied. This involves not only new optical designs, but also new approaches to the processes of designing and constructing 3D optical devices out of building blocks that are much smaller than the wavelength of light. In addition to enabling particularly small devices, such small building blocks interact with light based on different physical principles than those that apply to large optics. The research will be incorporated into a course at the University of Arizona, and undergraduate students and high school teachers will also partake in the research. Native American students and their educators, who are often disadvantaged in terms of their exposure to science and engineering, will be a major demographic target.Technical: The goal of this proposal is to use three-dimensional (3D) nanophotonics to enable imaging devices with angle, wavelength, and polarization sensitivity in significantly more compact and lighter weight systems than is currently possible. In existing angle-sensitive 3D light-field imaging approaches, the diffraction limit imposes a minimum useful pixel size. Although not previously demonstrated, nanophotonics offers the potential to significantly reduce the minimum pixel size, which can in turn allow for reductions in the size of any external optics. Novel high-speed optimization-based algorithms will be used to design 3D nanophotonic structures composed of metallic and/or dielectric nanoparticle building blocks. On individual pixels, different structures will selectively receive incoming light with specific incidence angles, polarizations, and/or wavelengths. Photonic nanostructures that cover entire blocks of pixels will also be designed to sort incoming light based on incidence angle, wavelength, and polarization. The nanostructures will be fabricated using an optical tweezer-based rapid prototyping approach. Colloidal nanoparticle building blocks will be chemically functionalized to bind when brought in contact with each other using the optical tweezers. After the nanophotonic structures have been fabricated on the image sensors, they will be tested under well-controlled lighting conditions using monochromatic laser sources directed at particular angles with particular polarizations, as well as in everyday broad-band, wide-field scenes. A compact and light-weight multimodality imaging device will be created. Its performance will be compared to existing light field imagers, hyperspectral imagers, and polarimeters.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.