New Designs Of Holographic Helmet Displays

When used with monochromatic light, holographic helmet displays have distinct advantages when compared to conventional helmet displays. Unfortunately, the holographic elements needed for such displays must perform over a large field of view, and generally suffer from severe aberrations. To overcome these aberrations it is necessary to holographically record complex wavefronts, which can not be obtained with standard optical components. A recursive design technique for obtaining the desired complex wavefronts from relatively simple intermediate holograms is developed. It is based on changing the geometries and the wavelength between the recording and readout of the intermediate holograms. The design technique is illustrated for a single holographic helmet display element having resolution of less then one miliradian over a field of view of 16°x16°.