Patent ID: 7787346
Filing Date: 2010-08-31
Classification: G03H,G11B,G11C

Abstract:
1. A hologram recording method, comprising: generating a signal light that is spatially modulated such that digital data is represented by an image of intensity distribution; irradiating the signal light on an optical recording medium after a Fourier transformation of the signal light is performed such that a zero-order component of the signal light comes into focus at a point removed from the optical recording medium; forming a diffraction grating in the optical recording medium by interference between the zero-order component of the signal light and a high-order component thereof; and recording digital data represented by the signal light as a hologram, wherein a focus position of the zero-order component of the signal light that is separated by a distance x represented by the following expression (1) from an intermediate point of the optical recording medium in the thickness direction, wherein the length of one side of a rectangular pattern in the image of intensity distribution representing the signal light before the Fourier transformation is 1, the wave length of the signal light is λ, the focal distance of a Fourier transform lens is f, the length of one side of each pixel in the image of intensity distribution is d, and the thickness of the optical recording medium is t, and the length l, the wave length λ, the focal distance f, the length d, the thickness t, and the distance x in the expression (1) are expressed using the same unit system.