Wide Field of View Lensing Spatially Variant Photonic Crystals

Research Objective: Demonstrate Spatially Variant Photonic Crystals (SVPCs) with beam guiding and wide Field of View (FOV) lensing capabilities at Short-Wave Infrared (SWIR: 1 – 2.5 µm) and Mid-Wave Infrared (MWIR: 3 – 5 µm) wavelengths. Develop and implement a novel 3D SVPC architecture to design SVPCs with spatial variation in both the size and orientation of unit cells to control the phase and propagation of incident light. Use an iterative process of design, fabrication, testing, and integration to optimize SVPC designs, fabrication parameters, and integration techniques to meet desired performance metrics. Develop individual SVPC lenses and arrays of SVPCs to capture and image light from a wide FOV (up to 100°) while remaining compatible with low Size, Weight, and Power (SWaP) platforms. Develop several SVPC designs based on requirements of potential Air Force use cases, e.g., miniaturized cameras, pixel arrays, fiber-tip sensors, and directed-energy laser systems. The final result of the Phase II will be a demonstration of an integrated SVPC device at the customer facility to provide wide FOV and beam guiding characteristics for an Air Force use-case such as drone-based imaging. Phase II Approach: SVPCs will be designed using Applied Optimization’s (AO’s) open-source toolkit for SVPC design and simulation, Wave-Point. Finite-Difference Time-Domain (FDTD) and wave-optic simulations will be performed to modify the 3D SVPC architecture and meet use-case requirements for imaging and energy direction. SVPCs will be fabricated using Two-Photon Polymerization (TPP). TPP using low-index photopolymer materials provides high-resolution fabrication of 3D SVPCs for interconnected, self-supporting devices that are compatible with silicon photonics. This approach enhances the scalability of product development and integration. Prototype devices will be characterized in the lab to evaluate lens and light guiding properties, e.g., FOV, transmission efficiency, focusing efficiency, polarization insensitivity, Point Spread Function (PSF), Modulation Transfer Function (MTF), and control of higher-order modes. The final integrated prototype device will be evaluated for additional use-case requirements such as control, imaging resolution, relay or delay time, cost, and SWaP. Phase I Feasibility: The proposed effort builds upon AO’s prior experience in the design and characterization of SVPCs and custom optical devices, e.g., from prior Internal Research and Development (IR&D) efforts, commercialized technologies, and SBIR/STTR projects. AO has partnered with the University of Dayton (UD) to develop practical SVPC devices for applications at SWIR/MWIR wavelengths. The project team has worked together for over 5 years for SVPC and custom optical design. AO has expanded SVPC designs and the Wave-Point toolkit’s capabilities using IR&D efforts to support our commercialization efforts and industry efforts. Taken together, this work constitutes Phase I Feasibility.