OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials;Space Technology;Sustainment OBJECTIVE: Develop and demonstrate additive manufacturing (AM) processes to produce metamaterial lenses process in Middle Wavelength Infrared (MWIR) (3 5 m) or Long Wavelength Infrared (LWIR) (8 12 m) bands derived from full-wave electrodynamic simulation. DESCRIPTION: Meta-optics present several benefits to modern optical technologies. First, they allow for extreme miniaturization of optical components, reduced size, weight, and power (SWaP) for optical systems. Second, they enable smart functions that are not readily available with conventional optics, such as integrating multiple functions in a single optical element. Third, the nanoscale volume of the resonators offers fast and real-time reconfigurability of optical functions. Most importantly, meta-optic provides a means for the Navy to develop optical components in the MWIR and LWIR, which is not accessible by convectional glass. With all of the benefits of meta-optics highlighted above, it is a challenge to produce meta-optical components. The current practice of producing meta-optics relies on simulations, creating a mask, using photo-lithography process, and then etching away the final product. This process is time consuming and has significant cost associated with it. Additionally, the small business awardee is relegated to materials that are complementary metal-oxide semiconductor (CMOS) friendly. If there is an error in the design or fabrication cycle the small business awardee must start the whole process from the beginning. To mitigate the exhaustive development and manufacturing cycle of a meta-optical component, the Navy is seeking an AM solution that would take a meta-optic design and 3D print the final product. The Navy also seeks to work with any material of choice that supports the MWIR and LWIR spectrums. The Navy also seeks to work with multimaterial meta-optic solutions. Create a meta-optical design using a n (10 < n < 3) sided polygon and demonstrate that the simulation produces a 10% diffraction limited lens of focal length 50 mm. Develop a method of preforming AM and simulate the production of meta-optical lens design using the AM process proposed by the awardee. Using the Phase I simulations produce a 25 mm meta-optical lens that is 10% diffraction limited with a focal length of 50 mm using AM process and equipment proposed by the awardee. PHASE I: Propose a concept for broadband LWIR metalens AM materials that meets the objectives stated in the Description. The concept will include specific prototypes, by which the proposed AM process technology will be demonstrated. These prototypes will subsequently be produced and used (in Phase II) to verify, by testing and analysis, the efficacy of the proposed AM concept. Demonstrate feasibility by a combination of analysis, modelling, simulation, and evaluation of proposed process steps against established manufacturing methods. The Phase I Option, if exercised, will include the initial process specifications, AM equipment requirements, test specifications, and capabilities description to build a prototype AM facility in Phase II. Determine necessary equipment and manufacturing process to fabricate planar optical elements. Produce initial proof-of-concept lenses using the design and manufacturing processes to show viable path to meeting Navy program requirements. The Phase I effort will include prototype plans to be developed under Phase II. PHASE II: Develop and demonstrate a prototype facility for AM of LWIR metalens. In this context, facility refers to the combination of equipment, tooling, and process steps required to demonstrate the end-to-end AM capability provided by the proposer, not the actual physical facility. Demonstration of the AM process (or multiple processes) will be accomplished by fabrication and evaluation of the prototype components and materials identified during Phase I. Multiple prototype components and samples are expected during execution of this Phase as the process development is assumed to be necessarily iterative in nature. However, at the conclusion of Phase II, at least one example of each proposed prototype component or material sample will be delivered to the U.S. Government with no fewer than five total prototype samples delivered overall. Test data will also be delivered with each prototype sample delivered. PHASE III DUAL USE APPLICATIONS: Provide representative prototype samples using the awardee's AM process to a U.S. Government laboratory and to a U.S. Government depot. Evaluate, by conventional metrology, the innovative optical surface with the flatness as detailed in the Description to ensure the AM process is on par with an optical flatness produced by common practice. Transition the AM process to a U.S. Government laboratory and to a U.S. Government depot. Perform testing and make improvements to the AM process based upon the U.S. Government's evaluations and results. Begin producing optical MWIR and LWIR AM components for field testing and use in military systems. Laser manufacturers, camera manufacturers, and imaging technology manufacturers will benefit from this AM technology because they can now specify custom-size optical components with unique MWIR and LWIR transmission profiles that are not currently available with conventional optical processing. REFERENCES: 1. She, A.; Zhang, S.; Shian, S.; Clarke, D. R. and Capasso, F. Large area metalenses: design, characterization, and mass manufacturing. Optics express, 26(2), 2018, pp. 1573-1585. https://doi.org/10.1364/OE.26.001573 2. Low-Loss, Low-Aberration, Numerical Aperture-Matched Microlens Arrays to Improve Coupling Efficiency onto Photonic Imaging Devices.: Navy SBIR 22.1 - Topic N221-079 SSP. SBIR-STTR. https://www.sbir.gov/node/2101805 3. Unal, B. AFRL-RX-WP-TR-2021-0133: Fundamental limits of nonlinear optical effects for metalens design with high index optical materials. United States Air Force, 2021. https://apps.dtic.mil/sti/pdfs/AD1154169.pdf 4. Benavides-Guerrero, J. A.; Gerlein, L. F.; Trudeau, C.; Banerjee, D.; Guo, X. and Cloutier, S. G. Synthesis of vacancy-rich titania particles suitable for the additive manufacturing of ceramics. Scientific Reports, 12(1), 15441, 2022. https://doi.org/10.1038/s41598-022-19824-y 5. Bougdid, Y.; Chenard, F.; Sugrim, C.; Kumar, R. and Kar, A. CO2 Laser Sintering of TiO2 Nanoparticles Thin Films for Improved Transmittance. Lasers in Manufacturing and Materials Processing, 2024, pp. 1-22. https://doi.org/10.1007/s40516-023-00241-6 KEYWORDS: Additive Manufacturing; AM; lens; LWIR; 3D Printing; Material Science; Metallurgy
