Holographic memory medium, holographic memory device and holographic recording device

• Main Author: MATSUMURA YOSHIYUKI,REDMOND IAN R.,MALANG KEITH
• Format: Patent
• Language: English
• Published: 26.09.2007
• Subjects: CINEMATOGRAPHY; ELECTROGRAPHY; HOLOGRAPHIC PROCESSES OR APPARATUS; HOLOGRAPHY; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHOTOGRAPHY; PHYSICS

Even when a tilt error is caused in a holographic memory in a direction perpendicular to a surface including optical axes of a signal beam and a reference beam (radial tilt direction), the signal beam and the reference beam are allowed to enter the holographic memory at adequate angles relative thereto at all times by suppression of the tilt error. A reference tilt hologram for specifying a reference incident angle of the reference beam in a radial tilt direction is recorded in advance on a holographic memory medium. During recording and reproducing operations, the reference beam is emitted to a recording position of the reference tilt hologram and the reference incident angle (reference angle Sr) of the reference beam in the radial tilt direction is detected based on a received light state. A tilt actuator ( 19 ) for displacing the holographic memory medium in the radial tilt direction is driven to adjust an incident angle of the reference beam in the radial tilt direction to the reference angle Sr. Then, the signal beam and the reference beam are emitted to the holographic memory medium to execute the recording and reproducing operations.