Fan-out elements recorded as volume holograms: optimized recording conditions

The recording of efficient fan-out elements as volume holograms is investigated by using the coupled-wave theory. In contrast to the results published in the standard literature, we find that the efficiency and the uniformity of regular fan-out elements depend strongly on the relative phases of the object waves, at least, if the thickness of the hologram is less than ~50 wavelengths. High efficiency and uniformity can be achieved by optimized recording conditions. At the same time, the required dynamic range of the holographic material becomes minimum.