Many industrial and consumer devices rely on controlling light at small length scales, for example, the machines used to make computer chips, the cameras in cell phones, and medical imaging devices, just to name a few. Miniaturizing such devices makes them lighter in weight, more energy-efficient, and often higher in performance because of the ability pack more functional components closer together in a smaller package. A current challenge is how to miniaturize three-dimensional (3D) components in devices that have elements smaller than 150 nm, which is about the same size as a virus, and only a bit smaller than the wavelength of visible light. Consumer-grade 3D printers have resolution that is ~1000 times worse than this. This proposal aims to develop new, relatively low-cost techniques to design and assemble 3D structures for photonic devices with elements as small as ~50 nm. In addition to device performance improvement tied to miniaturization, the creation of structures with such small elements can lead to materials with exotic optical properties that are not found naturally. These exotic optical properties can enable devices such as lenses with resolution beyond those of glass lenses, or devices like optical cloaks that bend light around an object. The research will be incorporated into courses at the University of Arizona, and the course modules will be shared with other educators via websites, professional meetings, publications, and outreach events. High schoolers and undergraduate students will also partake in the research.
Ultimate control over light requires control of the relative permittivities and permeabilities of materials over all three dimensions of space with deep sub-wavelength resolution. In a steady-state system, the behavior of light depends entirely on the 3D distribution of these properties. For example, studies of photonic metamaterials have shown that the patterning of heterogeneous materials at such deep sub-wavelength scales can enable negative refractive index, permittivity near zero, and ultra-high refractive index. Generally, the higher the resolution of the fabrication approach, the more compact the optical system and the higher its resulting optical resolution. However, a significant barrier to realizing this ultimate control over light is that there are currently no means to achieve deep subwavelength heterogeneous patterning in 3D structures for visible and near-infrared wavelengths. The goal of the proposed project is to design, fabricate, and test 3D nanophotonic components assembled out of precisely-positioned metallic and high-index dielectric colloidal building blocks of various shapes with ~50 nm, high-resolution feature sizes. Design approaches will use the coupled multipole method. High speed optical tweezers and biochemical linkages will be used to fabricate structures and devices out of >1000 building blocks. Devices that have previously only been theoretically proposed will be experimentally tested, including superresolution imaging devices and devices based on transformation optics.
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.
