Bragg degenerate model for fabrication of holographic waveguide-based near-eye displays

Effect of shrinkage in photopolymer film on the information transmitted through the holographic waveguide for near eye displays

Due to shrinkage in photopolymer materials, the angle of the reconstruction beam in holographic optical elements (HOEs) does not match with the Bragg condition, resulting in a decreased amount of light in the desired direction or loss of transmitted information to rematch the Bragg condition. Thus, to ensure final display features it is imperative to precompensate the shrinkage effect. We derived simplified expressions for precompensation in recording geometries of required HOEs in holographic waveguide-based Maxwellian near eye displays. An acceptable range of detuning from the Bragg angle is also analyzed. The experimentally measured 4.95% shrinkage in photopolymer film for 0° and 45° recording angles of beams was precompensated using -0.86∘ and 43.7° recording angles. Theoretical results are validated through simulation and experiments.