| US 7,512,054 B2 | ||
| Method for optical recording, method for optical reproducing, optical recording medium, and optical recording and reproducing apparatus utilizing holography | ||
| Kazuki Matsumoto, Kawasaki (Japan); Yuuji Kubota, Yokohama (Japan); Naru Ikeda, Yokohama (Japan); and Akiko Hirao, Chiba (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on Sep. 21, 2005, as Appl. No. 11/231,251. | ||
| Claims priority of application No. 2005-026605 (JP), filed on Feb. 02, 2005. | ||
| Prior Publication US 2006/0171284 A1, Aug. 03, 2006 | ||
| Int. Cl. G11B 7/00 (2006.01) | ||
| U.S. Cl. 369—103 [369/275.1] | 14 Claims |
| 10. An optical recording and reproducing apparatus which performs recording information to and reproducing information from
an optical recording media utilizing holography, the optical recording media having a holographic information recording region
and a region having wavelength reference marks with a periodic structure characteristic based on a recording base wavelength
to cause diffraction of a recording beam and a reproducing beam, the apparatus comprising:
a light source;
a spatial light modulator which generates an information beam and/or reference beam from a beam emitted from the light source;
an optical system adapted to irradiate the holographic information recording region of the optical recording media with the
information beam and the reference beam that are a recording beam, to irradiate the holographic information recording region
of the optical recording media with the reference beam that is a reproducing beam, and to irradiate the region of the optical
recording media in which the wavelength reference marks are formed with the recording beam or the reproducing beam;
a photodetector detecting a wavelength shift of the light source with respect to the recording base wavelength based on a
diffraction beam of the recording beam or reproducing beam with which the wavelength reference mark region of the optical
recording media is irradiated; and
a wavelength controller controlling a wavelength of the light source so as to reduce the wavelength shift.
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