Programmable computer generated holograms with large space bandwidth product

The key to programmable binary phase computer generated holograms (CGHs) is a controllable recording media with a robust phase modulation scheme. Magneto-optic and ferroelectric liquid crystal (FELC) devices have intrinsically robust π phase modulation schemes and FELC devices have produced high quality electrically programmable holograms. FELCs offer a means to create CGHs which are dynamic but the space bandwidth product (SBWP) is ultimately limited by the ability to electrically address more pixels. A fixed CGH may have a SBWP of 10⁸ whereas the programmable devices are of order 10⁴, and are unlikely to approach the SBWP of fixed devices. The authors present a combination of fixed and programmable holographic elements which multiplies the available SBWP of the programmable elements by orders of magnitude, with the potential to approach the SBWP of fixed elements