Multiplexing Holographic Waveguide Couplers in Photopolymer Material

Abstract

Augmented Reality headsets that are viable for the consumer market still face many optical challenges, including a limited field of view and complexity of the headset. The well-known current architectures such as HoloLens and Magic Leap employ surface relief grating coupler waveguides to produce images for the user. These waveguides are limited in FOV and can add bulk to the overall system. Volume holograms as waveguide couplers can be another solution to produce images for the user. This thesis discusses the theory behind volume holograms for use in augmented reality waveguide optical applications. Current generation AR solutions are discussed and the potential of photopolymer hologram material to match current optical specifications is simulated. For scalability and ease of manufacturing, the recording of such holograms should be at least as efficient and as costly as SRG couplers. A method to monitor the material response for better control of diffraction efficiency is described and used to experimentally verify the recording of a transmission hologram coupler for a waveguide. The same method is used to record a multiplexed transmission hologram coupler which verified simulations for multiplexed gratings. Expanded FOV is demonstrated with the multiplexed transmission hologram coupler. The capabilities and limitations of a commercially available photopolymer recording material are discussed along with techniques for future studies that can improve the performance of volume hologram couplers.