CAREER: Nonlocal Metasurfaces with All-Angle Control of Light

University Of Southern California, Los Angeles CA

Investigators

Abstract

Angle-resolved modulation of light is at the heart of technologies such as cameras, microscopes, LiDAR, Li-Fi, and augmented-reality devices. Miniaturization of these devices are important for mobile, wearable, medical (e.g., endoscope), and automobile applications. Nanostructures designed to tailor the flow of light can substantially bring down the size, weight, and cost of such devices, but a paradigm shift is necessary to come up with designs that impart the appropriate modulation for not just one but all of the incident angles of interest. This research program will build the analytical and numerical tools for designing photonic devices with all-angle control of light, as well as exploring new designs that can enable compact cameras with large field of view and high-speed spatial light modulators. The computational tools developed will be made open source. Knowledge created from this research program will be incorporated into a new graduate course on applied physics at USC. These activities are further integrated with teaching and outreach activities including high school and undergraduate students in the research program, creating STEM projects for high school students, and introducing interactive optics demos to K-12 classrooms. Optical metasurfaces provide a versatile platform for spatially-resolved modulation of the phase, amplitude, and polarization of light while being amendable to large-scale fabrication. However, the widely adopted unit-cell-based locally periodic approximation is inaccurate and suboptimal for large-angle operations, and local phase-shift profiles cannot describe angle-multiplexed responses which are fundamentally nonlocal. While designs based on full-wave simulations can in principle overcome these limitations, they are extremely time consuming given the large sizes of metasurfaces and the numerous input and output states involved. This research program will develop new numerical methods that are orders-of-magnitude more efficient in computing the transmission matrices of large-area metasurfaces, introduce new perfectly matched layers that can significantly reduce the computation domain of metasurface simulations, establish fundamental thickness bounds for nonlocal metasurfaces with a large field of view, and design and realize new classes of nonlocal metasurfaces that are enabled by the preceding tools including compact wide-field-of-view imaging systems that reach the fundamental bounds and high-speed metasurface spatial light modulators. Beyond metasurfaces, these studies will also improve the fundamental understanding of multi-mode optical systems and create numerical tools for the broader scientific community. 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.