Method for preparing colorful three-dimensional hologram based on holographic polymer dispersed liquid crystal grating

A method for preparing a colorful three-dimensional hologram based on holographic polymer dispersed liquid crystal gratings, comprising:

• (1) preparing with holography a holographic master which stores reflected (or transmitted) light wave information of a captured object in a medium of silver halide or dichromated gelatin;
• wherein the light wave information comprises amplitude and phase information;
• (2) mixing a photosensitizer, a co-initiator, a monomer capable of free radical polymerization and a liquid crystal ultrasonically and homogeneously to form a mixture, and perfusing the mixture into a liquid crystal cell by means of capillary action to prepare a holographic base board;
• (3) splitting, by means of a polarizing beam splitter, a 441.6 nm laser beam into two beams, wherein one beam is an object light, which first penetrates the holographic master and then irradiates the holographic base board, and the other another beam is a reference light, which irradiates the holographic base board directly without penetrating the holographic master;
• (4) using the object light to irradiate the holographic master at a Bragg angle to generate a beam of diffraction light carrying information of the captured object;
• using the diffraction light and the reference light to simultaneously irradiate the holographic base board;
• wherein when total optical paths of the two beams reaching the holographic base board are equivalent to each other, optical coherence occurs between the two beams, thereby causing monomer polymerization and consequent polymerization induced phase separation to obtain a colorful three-dimensional hologram based on holographic polymer dispersed liquid crystal gratings from which an image of the captured object can be observed in sunlight.