Patent ID: 7400567

Claim:
An optical information recording-reproduction apparatus comprising: a first laser light source; a spatial light modulator for generating reference light and information light from light beam emitted from the first laser light source; a relay lens for leading the reference light and the information light to a recording medium for recording information using holography; a first light receiving device which receives reflected light obtained by radiating the recording medium only with the reference light and reproduces the information; a second laser light source; a second light receiving device which receives reflected light obtained by radiating the recording medium with light beam from the second light source and provides servo signal; and driving means which moves at least one of the relay lenses perpendicularly to an optical axis according to the servo signal; wherein the light beam from the second laser light source merges with an optical system from the first laser light source to the recording medium between the relay lens moving perpendicularly to the optical axis and the spatial light modulator.