Uniformly Redundant Arrays
Holography performed with uniformly redundant arrays (URA) increase the signal to noise ratio of the holographic signal, which is especially important for high resolution holograms. It can be thought of as a type of multi-reference feature (as seen in figure 4) with the highest possible resolution proportional to the smallest feature sizes on the URA. High resolution URAs have been fabricated and are shown below. Experiments to perform high resolution holography using these URAs are underway.

