Method for preparing color holographic polymer dispersed liquid crystal grating

The invention relates to a method for preparing a color holographic polymer dispersed liquid crystal grating. According to the method, a multi-band exposure light path is set up, a reflection type liquid crystal spatial light modulator is adopted, different pictures with black and white strips are loaded on the reflection type liquid crystal spatial light modulator, and different sub-gratings are prepared; in this way, the devices of the light path do not need to be moved at all during exposure, convenience and fastness are realized, and repeatability is high; besides, due to the fact that exposure is conducted by means of RGB laser light and exposure angle remains unchanged, red light, green light and blue light on a displayer can be emitted at the same emergent angle based on the holographic recording and reconstruction principle, and chromatism-free stereo display image beam splitting is achieved; the polymer dispersed liquid crystal material adopted is a multi-light initiator and assisted initiator concurrent material, and the polymer dispersed liquid crystal material obtained finally can achieve exposure at multiple bands including red light 632.8 nm, green light 532 nm and blue light 441.6 nm. The left eye and right eye image beam splitting function is achieved in stereo display. The method has the advantages that image beam splitting effect is good and chromatism is completely avoided.