Holographic recording apparatus, holographic reproducing apparatus, holographic recording method and holographic reproducing method

A holographic reproducing apparatus for reproducing a hologram that is recorded in an optical recording medium with a recording light that is obtained by adding, in proximity to a light-convergence position where signal light modulated according to image data and reference light modulated by means of a pixel pitch come close to each other or overlap each other, a low-order component of the signal light obtained by Fourier transform and a high-order component of the reference light obtained by Fourier transform, the high-order component of the reference light having a spatial frequency region differing from that of the low-order component of the signal light,

• the holographic reproducing apparatus comprising:
• a light generation section that generates reading light which is substantially identical with the high-order component of the reference light;
• an illumination optical system that irradiates the optical recording medium with the reading light;
• a Fourier transform section that subjects light diffracted from the optical recording medium to Fourier transform;
• a signal light extraction section that extracts the signal light at a Fourier transform plane formed by the Fourier transform section;
• and
• a spatial frequency filter that extracts the high-order component from the reference light subjected to Fourier transform.

A method for recording a hologram, the method comprising:

• generating signal light modulated according to digital data;
• generating reference light modulated by means of a pixel pitch;
• adding, in proximity to a light-convergence position where the signal light and the reference light come close to each other or overlap each other, a low-order component of the signal light obtained by Fourier transform and a high-order component of the reference light obtained by Fourier transform, to thereby generate an added signal, the high-order component of the reference light having a spatial frequency region differing from that of the low-order component of the signal light;
• irradiating an optical recording medium with the added signal and reference light and
• extracting, using a spatial frequency filter, the high-order component from the reference light subjected to Fourier transform.

A method for reproducing a hologram that is recorded in an optical recording medium with a recording light that is obtained by adding, in proximity to a light-convergence position where signal light modulated according to image data and reference light modulated by means of a pixel pitch come close to each other or overlap each other, a low-order component of the signal light obtained by Fourier transform and a high-order component of the reference light obtained by Fourier transform, the high-order component of the reference light having a spatial frequency region differing from that of the low-order component of the signal light,

• the method comprising:
• generating reading light which is substantially identical with the high-order component of the reference light;
• irradiating the optical recording medium with the reading light;
• subjecting light diffracted from the optical recording medium to Fourier transform;
• extracting the signal light at a Fourier transform plane formed by the Fourier transform section;
• and
• extracting, using a spatial frequency filter, the high-order component from the reference light subjected to Fourier transform.