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The creation of new see-through near-eye displays (NEDs) architectures is a topic of intense research focus. A fundamental problem that each design must address is the field of view (FOV) and eyebox of NEDs are limited by etendue conservation for a fixed display optics size. Waveguide architecture provides the solution to increasing the eyebox in NEDs without increasing the optics size through exit pupil expansion. Brightness and uniformity are two key features of waveguide architecture. In this work, we focus on the brightness of the waveguide since the image uniformity can be compensated by the display engine. We show that the geometry of the waveguide sets a fundamental limit on the in-coupling efficiency for a given FOV. This limit can be used as a tool for waveguide designers to benchmark the in-coupling efficiency of their incoupler gratings. With this derived limit, we designed and optimized a metasurface-based grating (metagrating) and a surface relief grating (SRG) as in-couplers. The diffractive efficiencies of the two types of in-couplers were then compared to the theoretical efficiency limit. The metagrating's 28% efficiency surpasses the SRG's 20% efficiency and nearly matches the geometry-based limit of 29% due to the superior angular response control of metasurfaces compared to SRGs. This work provides a new understanding of the brightness efficiency limit of waveguide-based combiners and paves a novel path toward implementing metasurfaces in efficient waveguide AR displays. 

Metaforms are novel optical components formed by conforming a metasurface to a freeform substrate. Metaforms can be a powerful solution when designing compact imaging systems such as augmented reality displays. Given the rotationally variant nature of the metaform substrate and the difficulty of metasurface fabrication on curved substrates, the proper alignment of the metasurface nanofeatures to the freeform substrate is essential. Thus, to seamlessly bridge the metaform design, manufacturing, and metrology, we developed a software tool that automatically generates ISO standard highaccuracy CAD models for the designed metaform components. 

Active tracking enables higher precision in tracking the positions, orientations, and states of the virtualized objects. STEAMVR Lighthouse tracking base-stations can be used for tracking specific objects. However, current solutions are bulky and costly. The overall goal of this research work was to reduce the size and cost of active VR trackers to enable their attachment to ever smaller physical tools and objects to be tracked in the real world and displayed in a virtual reality environment.