Holographic elements with high efficiency and low aberrations for helmet displays.

A recursive design technique for forming holographic elements which can be incorporated into helmet displays has been developed. To ensure that the holographic elements have low aberrations and high diffraction efficiency they must be recorded with complex wavefronts. These wavefronts are derived from relatively simple intermediate holograms whose readout geometry and wavelength differ from those during recording. The overall recursive design technique is illustrated for a single holographic helmet display element having resolution of less than 0.8 mrad and diffraction efficiency of more than 80 percent over a field of view of 16 degrees x 16 degrees .