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.

A holographic characterization and playback apparatus is provided, which includes a light source, an optical path-forming optical system for separating the light emitted from the light source into a probe light and a reference light of different polarizations, and combining optical paths of the probe light and the reference light.

A holographic characterization and playback apparatus is provided, which includes a light source, an optical path-forming optical system for separating the light emitted from the light source into a probe light and a reference light of different polarizations, and combining optical paths of the probe light and the reference light.

An optical information recording and reproducing device that records information on a recording medium and/or reproduces information on the recording medium, using holography is configured to include a laser light source that performs irradiation with laser light, a first light-shielding portion which is capable of switching between transmission and shielding of laser light emitted from the laser light source, and a driving circuit that drives the switching between transmission and shielding of the first light-shielding portion, and a first movement portion that moves the first light-shielding portion.

An optical information recording and reproducing device that records information on a recording medium and/or reproduces information on the recording medium, using holography is configured to include a laser light source that performs irradiation with laser light, a first light-shielding portion which is capable of switching between transmission and shielding of laser light emitted from the laser light source, and a driving circuit that drives the switching between transmission and shielding of the first light-shielding portion, and a first movement portion that moves the first light-shielding portion.

Methods and systems for performing dynamic aperture holography are described. Examples include a method of recording multiple holograms in a photosensitive recording medium, where multiple signal beam angular apertures used to record the multiple holograms differ from each other. The multiple signal beam angular apertures can facilitate using a larger range of reference beam angular apertures. The multiple holograms are typically multiplexed, and examples of dynamic aperture holography enable packing the multiplexed holograms more densely in the recording medium. Some dynamic aperture holography systems include monocular objective lens architecture.

Methods and systems for performing dynamic aperture holography are described. Examples include a method of recording multiple holograms in a photosensitive recording medium, where multiple signal beam angular apertures used to record the multiple holograms differ from each other. The multiple signal beam angular apertures can facilitate using a larger range of reference beam angular apertures. The multiple holograms are typically multiplexed, and examples of dynamic aperture holography enable packing the multiplexed holograms more densely in the recording medium. Some dynamic aperture holography systems include monocular objective lens architecture.

A light information recording/reproducing apparatus can improve the optical efficiency of an optical system at the time of reproduction to thereby improve the reproduction transfer rate. An optical element (for example, an optical isolator), which removes a return light beam of a light beam, is arranged such that the light beam passes through the optical element at the time of recording information in an optical information recording medium and such that the light beam does not pass through the optical element at the time of reproducing information from the optical information recording medium.

A light information recording/reproducing apparatus can improve the optical efficiency of an optical system at the time of reproduction to thereby improve the reproduction transfer rate. An optical element (for example, an optical isolator), which removes a return light beam of a light beam, is arranged such that the light beam passes through the optical element at the time of recording information in an optical information recording medium and such that the light beam does not pass through the optical element at the time of reproducing information from the optical information recording medium.

A system determines the data stored on a portion of magnetic media by obtaining an image that represents the magnetic state of the portion of magnetic media using a magneto-optic image sensor. In an example, the image sensor is connected to a mechanism that moves over the portion of magnetic media, and the system takes a plurality of images which are stitched together into a composite image of the state of the portion of magnetic media. The system analyzes the image to identify regions that contain data, extracts the encoded data from the regions. The encoded data is decoded in accordance with an encoding scheme used by the portion of magnetic media. In some examples, a file structure is applied to the data and data files are recovered from the image. In various examples, the portion of magnetic media can be hard disk media, floppy disk media, or magnetic tape.