A Holographic Projection System With an Electrically Adjustable Optical Zoom and a Fixed Location of Zeroth-Order Diffraction

An electrically tunable optical zooming holographic projection system with a fixed location of zeroth-order diffraction is demonstrated. By using two liquid lenses and an encoded Fresnel lens on a liquid crystal on silicon (LCoS) panel, the size of the projected image of the holographic projection system is changeable; meanwhile, the locations of both of the zeroth-order diffraction and the first-order diffraction are unchanged. Therefore, the zeroth-order diffraction can be removed by using a fixed optical high-pass filter. We can use it to realize an image size matching system for green light (532 nm) and red light (632.8 nm) without any positional motion of the optical elements. The optical zoom function enhances the feasibility to realize a high-resolution full-color holographic projection system.