Initial phase assignment method for synthesizing computer-generated hologram

摘要

Random phase is usually assigned to the amplitude of the desired image to synthesis the phase-only computer-generated hologram(CGH). As a matter of fact, the CGH can be obtained directly if proper phase is assigned. But it is rather difficult since there are infinite ways of phase assignment. Based on the symmetry, a new deterministic binary phase coding technique is introduced in this paper. According to this method, the amplitude of the desired image is coded by a binary array derived form the desired image itself. The coarse CGH can be obtained by applying inverse discrete Fourier transform of the previous result. In order to get higher diffraction efficiency the usual iterative method is used to optimize the CGH. Using this method we have obtained several CGHs with high diffraction efficiency. The pattern of the binary CGH is transferred into the glass plate by inductive coupled plasma (ICP) technology. Experimental results are also given in this paper.