A large aperture achromatic holographic Risley prism equivalent system is proposed which provides conformal and fast scanning using ultra-light weight piezoelectric motors to achieve a large scan angle. The system is very efficient, simple and easily replicated. The central null issue normally associated with Risley prisms is eliminated with a 3rd weak achromatic displacement grating between the outer achromatic prism equivalent gratings. Beam characteristics are well preserved and it can handle high optical power. Diffraction efficiency is = 93% for a single holographic phase grating. Chromatic aberration is eliminated using a compensating hologram so the scanner operates over a broad spectral range. Zoom capability and optical power can be incorporated into the system to further extend its versatility eliminating external optics and reducing the size, weight and power requirements.
