Patent ID: 7835052

Claim:
A hologram recording method comprising: generating signal light which has (a) a periodic first intensity distribution that expresses a periodic pattern by a first light/dark image and (b) a second intensity distribution that expresses binary digital data by a second light/dark image, wherein the first intensity distribution and the second intensity distribution have different spatial frequencies, and the first intensity distribution and the second intensity distribution are overlapped such that only portions of one of the first intensity distribution or the second intensity distribution corresponding to light portions of the other one of the first or second intensity distribution are superimposed at the light portions of the other one of the first intensity distribution or the second intensity distribution; Fourier transforming the signal light; illuminating Fourier transformed signal light and reference light simultaneously on an optical recording medium; and recording the signal light as a hologram, wherein the signal light is generated and made to be incident in the optical recording medium without passing through a phase modulating element.