To reduce an influence of stray light and stably record/reproduce high-quality data in holographic recording/reproduction. A holographic memory device includes an optical system that guides a reference beam to an optical information recording medium at a desired angle of incidence, a control part that controls the angle of incidence of the reference beam generated in the optical system, and a lens part that images the reference beam in a desired position of the optical information recording medium. Further, at least a first light beam at a first angle and a second light beam at a second angle different from the first angle are output from the optical element, and the optical element is provided so that the first light beam may propagate within an effective diameter of the lens part and the second light beam may propagate to an outside of the effective diameter of the lens part.

The purpose of the present invention is to provide a hologram reproducing apparatus and a hologram reproducing method, which are suitable for reproducing hologram. The purpose can be achieved by means of a hologram reproducing apparatus, which reproduces information signals by irradiating an optical information recording medium with reference light, and a hologram reproducing method for the hologram reproducing apparatus. The hologram reproducing apparatus is characterized in being provided with: a polarization conversion section, which converts polarization of diffracted light that is generated when the optical information recording medium is irradiated with the reference light; a light receiving section, which receives the diffracted light having the polarization thereof converted by means of the polarization conversion section; and a servo signal generating circuit section, which generates signals for moving the optical information recording medium or the polarization conversion section using the diffracted light received by means of the light receiving section.

An optical information recording apparatus and method thereof for recording information in a holographic medium. The apparatus includes a laser source which generates a reference beam and a signal beam to record the information in the holographic medium, a sensor which detects a vibrational amplitude over a time period applied to the optical information processing apparatus for recording the information, an operational circuit which calculates from the vibrational amplitude at least one statistical measure of the vibrational amplitude; and a processor programmed to control a recording mode such that the processor evaluates the calculated statistical measure to determine continuation of a recording operation to the holographic medium.

An optical information recording/reproducing device which reproduces information from an optical information storage medium in which an interference pattern between a signal beam and a reference beam is recorded as page data includes a controller, a laser light source, a split part, an angle variable part, an optical part, a first light detector, and a second light detector, and the controller controls the angle variable part based on a control signal generated from a first signal detected by the first light detector and a second signal detected by the second light detector.

An optical information recording/reproduction device is capable of appropriately correcting the angle of a reference beam during data reproduction even when a wavelength deviation or an angle deviation in multiplexing and vertical directions of the reference beam occurs in a holographic memory recording medium. The optical information reproduction device has a laser light source that generates a reference beam; an image-capturing unit that detects a diffraction ray to be reproduced from the optical information recoding medium; and an optical detection unit that has at least two light-receiving surfaces and is used for detecting a diffraction ray reproduced by irradiating the reference beam on the optical information recording medium. The device also has a light-shielding unit that shields part of the diffraction ray detected by the optical detection unit; and an error signal calculation unit that generates an error signal from a detection signal outputted by the optical detection unit.

An optical information reproducing device which reproduces information from an optical information storage medium recording, as the information, a hologram which is an interference pattern between a signal beam and a reference beam, the hologram corresponding to an angle of the reference beam being a page, the device includes an image distortion learning unit which detects, based on a two-dimensional reproduction signal generated by reproducing the page, a marker which is a known pattern for detecting a position of two-dimensional data relating to the page, and learns a distortion amount which is the difference between a position of the detected marker and an ideal position, a detection unit which detects, based on the distortion amount, position information on the marker from the page, and an image distortion correction unit which corrects, based on the position information on the marker detected by the detection unit, an image distortion in the page.

In relation to recording and reproducing of a hologram, consideration has not thus far been given to crosstalk among adjacent pages Information is recorded by writing onto a holographic medium, an interference pattern formed by signal light and reference light, and the recorded information is reproduced by the reference light being projected on the interference pattern. According to the method, when angle multiplexing recordings in units of pages is carried out in a holographic medium by changing the angle of incidence of reference light, and if a stack is defined as a unit of angle multiplexing recording in the same location in the holographic medium and a book is defined as a set of multiple stacks with shifted recording positions, for adjacent stacks therein, recording is carried out by allotting, between the reference light angles for one of the stacks, reference light angles for the stacks adjacent thereto.

An optical information recording apparatus and method thereof for recording information in a holographic medium. The apparatus includes a laser source which generates a reference beam and a signal beam to record the information in the holographic medium, a sensor which detects a vibrational amplitude over a time period applied to the optical information processing apparatus for recording the information, an operational circuit which calculates from the vibrational amplitude at least one statistical measure of the vibrational amplitude; and a processor programmed to control a recording mode such that the processor evaluates the calculated statistical measure to determine continuation of a recording operation to the holographic medium.

An optical information recording/reproducing apparatus and method thereof which compensate for the effect of mechanical instability on holographic data storage. A time dependent deviation profile of an optical beam during recording is determined. The time dependent deviation profile is related to a phase profile to be applied to a reference beam during recording or reproduction of a hologram, and the related phase profile is applied to the reference beam during recording or reproduction of the hologram.

An optical information recording/reproducing apparatus and method thereof which compensate for the effect of mechanical instability on holographic data storage. A time dependent deviation profile of an optical beam during recording is determined. The time dependent deviation profile is related to a phase profile to be applied to a reference beam during recording or reproduction of a hologram, and the related phase profile is applied to the reference beam during recording or reproduction of the hologram.