Material-Constrained Optimization of Liquid Crystal-Based Holograms

A novel material-constrained method for the design of liquid crystal optical devices - computer-generated liquid crystal-based holograms - and their manufacture using photo-patterning is demonstrated. The developed topology optimization method is compared to the Gerchberg-Saxton algorithm, and key advantages and disadvantages are outlined. The key novelties and advantages of the method are that it accounts for the natural relaxation and material properties of the liquid crystal and that it can account for different material or manufacturing constraints, such as maximum optical axis gradients. The viability of the method is applied for different binary and greyscale target images of varying complexity, target image sizes, and algorithms that account for the material properties of the liquid crystal. Finally, with the topology optimization design approach and photo-patterning, it is possible to produce high-accuracy and high-contrast liquid crystal-based computer-generated holograms. Computer-generated hologramsbased on liquid crystals are efficient flat optical devices that are relatively cheap and easy to manufacture while also having a broad area of applications, including augmented reality and indoor lighting solutions. The TO-CGH algorithm with gradient limiter functions considers the material constraints of liquid crystals and consequently produces holograms of better quality. image