HOLOGRAM RECORDING AND REPRODUCING DEVICE, AND ANGULAR MULTIPLEXING RECORDING AND REPRODUCING METHOD

摘要

A hologram recording and reproducing device and an angular multiplexing recording and reproducing method capable of detecting an angular error signal for which, in a two-beam angle multiplexing method, high-speed reproducing can be achieved with a superior recovered signal. A branch element branches a light beam, emitted from a light source, into a signal light and a reference light. Angle-variable elements modify the incident angle of the reference light that is incident to the optical information recording medium. A spatial light modulator adds information to the signal light; and an objective lens radiates the signal light to the optical information recording medium. An imaging element detects diffracted light generated from a recording region when the reference light is radiated upon the optical information recording medium; a detection system detects at least two angular error signals for controlling the angle-variable elements; and switching is performed between the two angular error signals.

主权项

1. A hologram recording/reproducing device which records an information signal by casting a signal beam and a reference beam upon an optical information storage medium to thereby form a hologram and reproduces an information signal by applying a reference beam to a hologram within an optical information storage medium, the device comprising:
a light source which emits an optical beam; a splitting unit which splits an optical beam emitted from a light source into a signal beam and a reference beam; an angle adjustment unit for varying an angle of incidence of a reference beam incident on an optical information storage medium; a spatial light modulation unit for adding information to a signal beam; an objective lens for casting a signal beam upon an optical information storage medium; an imaging unit for detecting a diffracted beam generated from a hologram within an optical information storage medium when casting the reference beam onto an optical information storage medium; and a detection unit for detecting at least two, first and second angle error signals for controlling an angle-variable unit, wherein the first angle error signal is generated from a signal detected from the diffracted beam, wherein control is performed with a second angle error signal after control is performed with the first angle error signal to reproduce.