Patent ID: 7236277
Filing Date: 2007-06-26
Classification: G03H,G11B

Abstract:
1. A holographic recording method comprising: applying light for recording or reproduction to a holographic recording medium comprising at least a recording layer with a thickness L which comprises a photorefractive index-changing material as a recording layer material, the recording layer material having an absorption coefficient α, wherein the optical density αL expressed by the product of the absorption coefficient α and the thickness L is in a range approximately from 0.3 to 2.0, wherein the recording is performed by simultaneously applying signal light at a first incident angle and reference light at a second incident angle different from the first incident angle to the recording layer, the reference light is applied at two or more different angles to the recording layer for the purpose of angle-multiplexed storage, and first reference light that enters the recording layer at a first angle forms an angle Δθ with second reference light that enters the recording layer at a second angle different from the first angle, wherein the angle Δθ (angular space) satisfies the formula: wherein Δθ represents an angular space (deg), n represents an integer of at least 2, λ represents the wavelength (μm) of the signal and reference lights applied at the time of recording, L represents the thickness (μm) of the recording layer, and θ represents an angle (deg) which the first reference light forms with the signal light applied to the recording layer at the time of information recording.