A Scalable Technology Platform for Creating Meta-Surface Based Optics and Waveguide Combiners for Augmented Reality

Optics is increasingly important in modern life, and advances in nanostructure-based flat optical devices hold great promise for revolutionary new opportunities in the display space. Augmented and Virtual Reality (ARVR) are expected to enable the next ubiquitous computing and communication platform.^[1] Augmented Reality, Optical metasurfaces also leverage engineered nanostructures to offer the possibility of extreme wavefront control, enabling further miniaturization of imaging and display optical systems and exciting new applications not achievable with conventional optics. ^[2,3]<br/>The Engineered Optics™ group at Applied Materials is enabling thinner, light-weight optical systems with precise wavefront engineering to make possible novel optical devices. We have leveraged Applied Materials’ materials engineering expertise to develop a platform for the precision fabrication of nanostructured optical devices on 300mm glass wafers, as well as metrology, optical performance characterization, and back-end assembly of these devices. With this platform, we are producing waveguide combiners for AR/VR applications and optical metasurfaces for multi-functional wavefront control in the near infrared.An essential element in designing the process and making choices for equipment is scalability, laying the foundation for large scale industrial manufacturing in a later stage We have opted to focus on the use of optical lithography Nano Imprint Lithography and a 300 mm equipment for all the etch and deposition steps. This leverages all the experience and the availability of equipment from the Semiconductor Industry.<br/>Waveguide combiners are a key component in lightweight augmented reality headset or glasses systems, but are difficult to fabricate to the high precision required for simultaneous high optical image quality of the AR content and clear vision of the real world.^[1<br/>The Engineered Optics platform includes a fully integrated front-end process flow to make surface relief grating-based waveguide combiner devices for our customers. All our tools are customized to enable handling of transparent substrates of a variety of refractive indices and thicknesses. We produce binary and slanted nanostructures using UV or nanoimprint lithography and etch in high-quality, low-loss optical materials. We can process single- or double-sided devices with high alignment fidelity, and can create desired features with global and local-area processing techniques.<br/><br/>The Engineered Optics platform offers full end-to-end capabilities: after front-end fabrication on 300mm substrates, we optically characterize device performance at the wafer level, then complete back-end singulation, edge blackening, stacking assembly, and final testing. Completed waveguide combiner devices can then be integrated with light engines and appropriate electronics, power sources, and housings to create final AR glasses or headset devices.<br/>The Engineered Optics platform also enables direct fabrication of optical metasurfaces on transparent substrates, without transfer from silicon substrates. We can fabricate the extremely high aspect-ratio structures required for full 2π phase control in a variety of extremely low-loss, high-refractive index optical materials.<br/>We are also looking at photonic integrated circuits, optical computing, optical data communication, and beyond.<br/><b>References</b><br/>B. C. Kress and I. Chatterjee, Nanophotonics, 10 (1), 41-74 (2021).<br/>F. Capasso. Nanophotonics, 7 (6), 953-957 (2018).<br/>V.-C. Su, C. H. Chu, G. Sun, and D. P. Tsai, Opt. Express 26, 13148-13182 (2018).