Improvement of computer-generated disk hologram

Abstract

We have been investigating the computer-generated disk hologram (CGDH). Since general flat format hologram has the limited viewable area, we usually cannot see the other side of the reconstructed object. Therefore, we proposed the computer-generated cylindrical hologram (CGCH) to realize the 360 degrees viewable hologram. However, the CGCH has the special shape, it is difficult to construct the CGCH and the calculation amount is too large. In contrast, a disk type hologram is also well known as the 360 degrees viewable hologram. Since the disk hologram is the reflective type flat hologram, the setup of reconstruction is very easy. However, there was few report of the disk hologram by the computer-generated hologram. Due to the lack of the spatial resolution of our output device, the hologram cannot provide the large diffraction angle. In addition, the viewing zone is depended on the hologram size (of course, the maximum size of the fringe pattern is decided on the special frequency of the out put device), the calculation amount is also large (calculation amount of the CGDH is about quarter of the CGCH). In our previous study, the computer-generated disk hologram was realized. However, since the relation between the vertical viewing zone and reconstructed image size is trade-off, the size of the reconstructed image and view zone is not enough for practical use. Therefore, to improve both parameters, we modified the fringe printer to output the high resolution fringe pattern for the disk hologram.