Study On The Design Of Binary Phase-only Holograms

Compared with two-dimensional display technology,holographic 3D display technology can provide the depth information of all 3D scenes that can satify the needs of human eye physiological observation.optical holographic can only record and reproduce the real objects,however,compuer generated hologram can realize real and virtual 3D scene dynamic 3D display.compuer generated phase-only holograms can obtain any light intensity distribution.it has very high diffraction efficiency when compared with amplitude holograms.Holographic three dimensional display technology can realize real time three-dimensional display by spatial light modulator or photorefractive material.But spatial light modulator lacks of resolution and the refresh rate of photorefractive materials is not up to the requirement of video display.VO2 films have the characteristics of short transition time and large refractive index change,so we can design binary phase-only holograms to modulate VO2 film materials.In general,we can use VO2 film materials as new materials used by photorefractive holographic 3D display.The phase distribution of phase-only hologram is between 0-2 ?,binaryzation of phase-only holograms changes the value of phase to 0 or ? which makes great loss of information.The spectrum distribution of the image will affect the information loss of binaryzation.The greater the dynamic range of the spectrum is,the greater the loss of information is made and the more smooth the spectrum is,the less loss of information is made.The Fourier spectrum has a great feature that the spectrum of high frequency region is smooth and the dynamic range of low frequency is large.We reconstruct the spectrum of high frequency region and low frequency region respectively by combing direct binary search.The reconstructed image is made by adding the intensity of two images.The feasibility of this binaryzation method is verified by simulation.We compare this method with Fourier transform,G-S method,iterative stepwise method and direct binary search method.The result shows that optimizing binary phase-only holograms from the perspective of image spectrum helps improve the quality of reconstructed image.