The Study Of White Light Displaying Holograms Of Large Scene Depth

Rainbow hologram and reflection hologram are two large kinds of laser holograms which could be displayed by white light. On the final aim of improving and prolonging their three-dimensional displaying ability, the complete probe and deep analysis on the theories of rainbow hologram and reflection hologram have been done in this dissertation, and lots of experimental verification have been done depending on the theoretical analysis above. The large scene depth rainbow holograms and reflection holograms of high quality have been made. This dissertation could be divided into two large parts:1. The theoretical probe and experimental making of large scene depth rainbow hologram. The scene depth of reconstruction image of rainbow hologram is determined by the width size of slit in making process and viewing distance: the narrower the slit and the farther viewing distance are, the larger the scene depth will be. In normal condition, the resolution of image of the rainbow hologram will be brought down and the speckle noise will be obvious if the slit is too narrow. Meanwhile, it would not conform to people's viewing habit if the viewing distance is too farther. In view of these conditions above, lots of experimental work has been done in this dissertation. Via making the high quality Fresnel holograms as masters in the first step in the experiment of making the large scene depth rainbow hologram with two-step method, the difficult in experiment (in the second step) caused by undersize slit has been came over, and lots of experiment were done to select making parameters in the second step, the high quality large depth field rainbow holograms have been done as the result. The results of experiment showed that the rainbow hologram which's reconstruction image was deep as 63 centimeters could obtain the satisfied viewing effect in the condition that reconstructed by normal dot source white light and viewing at 1 meter or even more near.2. The theoretical and experimental development of large scene depth reflection hologram. According to the image relationship, using the uniform coupled wave theory and the bragg condition, image blur of reflection hologram caused by being reconstructed by white light source has been analyzed and discussed concretely, and the expressions of the color blur and linear blur were achieved. Such a difference has been pointed out that if the reflection hologram is constructed by white light source, the color blurs and linear blurs caused by different dots on the reflection hologram, have different effects for the same reconstruction image point. Basing on the above analysis, the expression of the scene depth of reflection hologram has been advanced. The analytic result shows that the scene depth of reflection hologram's reconstruction image would be affected markedly by recording and reconstructing angle and the viewing distance. When the reflection hologram was reconstructed vertically, it would have the most ability to express its scene depth. The one step and two-step large scene depth reflection holograms which're reconstruction images were deep as 63 and 83 centimeters have been done in the experiment.Experimental study shows that, it would be necessary to use the small width size of slit in experiment to obtain the satisfied white light reconstruction image of large scene depth rainbow holograms. To reduce the width size of the slit, one hand the blur of reconstruction images would be restricted thereby benefiting for viewing, but another hand, the parallax of reconstruction image at the vertical direction of slit's length would lose seriously, thereby the three-dimensional effect of the reconstruction image would be not strong on the contrary.Differing from the large scene depth rainbow hologram, as recording and reconstructing the large scene depth reflection hologram, the three-dimensional effect of the reconstruction images of large depth of field reflection holograms are very strong because that the spatial freedom degree of objects and images information are only restricted by the aperture of record medium mainly, and the aperture of record medium could be very large. This part work in this dissertation has developmental significance in theory and experimental exploration, and there are important significances in prolonging the artic value of three-dimensional display of reflection hologram.