Optical element and manufacturing method thereof

摘要

A hologram that can obtain high diffraction efficiency when reconstructed and is superior in productivity is provided. An arbitrary object image and a recording surface in which representative points are disposed with predetermined pitches are defined by use of a computer. At the position of each individual representative point, a complex amplitude for the wave front of object light emitted from the object image is calculated, and a complex amplitude distribution is calculated on the recording surface. This complex amplitude distribution is expressed by a three-dimensional cell having a groove in the surface thereof. Four kinds of groove depths are defined in accordance with the phase ¸ , and seven kinds of groove widths are defined in accordance with the amplitude A. Thereby, 28 kinds of three-dimensional cells in total are prepared, and a three-dimensional cell corresponding to the phase ¸ and amplitude A of the complex amplitude for the representative point is disposed at the position of each representative point. One of the 28 kinds of three-dimensional cells is disposed at the position of each representative point on the recording surface, and thereby a hologram-recording medium is formed as a set of three-dimensional cells. A reconstructed image is obtained by the phase/amplitude modulating function of the groove part of each cell.