Abstract: A hologram recording apparatus that records a hologram on a recording layer of a hologram recording medium by causing interference between signal light modulated in accordance with record data and reference light from the same light source as that of the signal light is provided. The apparatus includes: a signal light spatial light modulating section that displays a signal light pattern for causing the signal light; a reference light spatial light modulating section that displays a reference light pattern for causing the reference light; a control section that controls the form of the signal light pattern to be displayed on the signal light spatial light modulating section and the form of the reference light pattern to be displayed on the reference light spatial light modulating section and controls optical energy of the signal light and reference light; and a temperature sensor that senses the temperature of the hologram recording medium.

Abstract: A holographic recording and reproducing apparatus is provided. The holographic recording and reproducing apparatus includes a signal-beam spatial light modulating unit that displays a signal beam pattern for a signal beam, a reference-beam spatial light modulating unit that displays a reference beam pattern for a reference beam, and a controller that controls the mode of the signal beam pattern and that of the reference beam pattern. The controller controls the modes of at least two signal beam patterns and the modes of at least two reference beam patterns. A first reference beam is made to interfere with a first signal beam based on first recording data to record the data as a first hologram in a predetermined area of the holographic recording medium. A second reference beam is made to interfere with a second signal beam based on second recording data to record the data as a second hologram such that the second hologram is superimposed on the first hologram.

Abstract: A hologram recording and reconstruction apparatus records and reconstructs a hologram in a recording layer of a holographic recording medium using a signal light beam and a reference light beam is provided. The hologram recording and reconstruction apparatus includes an objective lens for allowing the signal light beam, the reference light beam, and a diffracted light beam to pass therethrough, a spatial light modulator on which a reference light beam pattern for generating the reference light beam is displayed, a temperature sensor for detecting the temperature of the holographic recording medium, and a control unit for controlling the spatial light modulator to reduce the reference light beam pattern so that the reference light beam passes through the more inner portion of the objective lens or enlarge the reference light beam pattern so that the reference light beam passes through the more outer portion of the objective lens in accordance with the temperature.

Abstract: A hologram recording/reproducing device includes a laser light source emitting laser light; a spatial light modulator generating signal light and reference light from the laser light emitted from the laser light source, the signal light and the reference light traveling in a common light path; a first relay lens system including a first shielding plate at a focal position thereof and transmitting the signal light and the reference light generated by the spatial light modulator, the first shielding plate having a pinhole whose size is 1 to 2 times a Nyquist size; a phase modulating element disposed at a conjugate plane of the signal light and the reference light transmitted through the first relay lens system; an objective lens converging the signal light and the reference light transmitted through the phase modulating element on a hologram recording medium; and a light receiving system disposed between the phase modulating element and objective lens and receiving light returning from the hologram recording me

Abstract: A hologram recording apparatus includes a signal-beam spatial light modulating section, a reference-beam spatial light modulating section, and a control unit. A signal beam pattern generates a signal beam. A reference beam pattern generates a reference beam. The control unit controls the shapes of the two beam patterns. A data-recording signal beam pattern is displayed on the signal-beam spatial light modulating section and a data-recording reference beam pattern is displayed on the reference-beam spatial light modulating section so that a data-recording hologram is formed in a predetermined area of a holographic recording medium. An encryption signal beam pattern for encrypting the data-recording hologram is displayed on the signal-beam spatial light modulating section and an encryption reference beam pattern is displayed on the reference-beam spatial light modulating section so that an encryption hologram is formed in the same area as the predetermined area of the holographic recording medium.

Abstract: A hologram recording apparatus for carrying out holographic recording by emitting a signal beam and a reference beam onto a holographic recording medium includes a laser light source configured to output a pulsed laser beam, a splitter configured to split the laser beam into a signal beam and a reference beam, a spatial light modulator configured to modulate the signal beam or both the signal beam and the reference beam, and a controlling unit configured to control the spatial light modulator to modulate at least one of the signal beam and the reference beam with a totally dark pattern for a predetermined period of time, wherein the predetermined period begins no later than the start of the risetime of a pulse of a laser beam output from the laser light source.

Abstract: A holographic recording and reconstructing apparatus includes a laser light source for emitting a laser beam, a beam splitting element for splitting the emitted laser beam into a signal beam and a reference beam, a light modulating element for modulating the signal beam, an optical system for collecting the modulated signal beam and the reference beam onto a reflection hologram recording medium at substantially the same location, a light detection element for detecting a reconstructed light beam from the hologram recording medium, and wavelength shifting means for shifting the wavelength of the laser beam used during reconstruction from the wavelength used during recording.

Abstract: A hologram recording/reproducing device includes a recording/reproducing optical unit performing recording and reproducing operations on a hologram recording/reproducing medium. The optical unit includes a laser light source emitting laser light; a spatial-light modulator generating signal light and reference light from the laser light, the signal light and reference light having a common light path; a phase mask disposed near the modulator or in a conjugate plane of the modulator and transmitting at least the reference light; and an objective lens including a first lens portion and a second lens portion. The first lens portion is disposed at an inner peripheral portion of the objective lens and serves as a Fourier transformation lens focusing the signal light to a predetermined point.

Abstract: A hologram recording device can easily perform multiplex recording/reproduction on a hologram recording medium. The hologram recording device includes an optical system and a distance controlling mechanism. The optical system focuses on a substantially same location of a hologram recording medium a signal light modulated at a light modulating element and a reference light whose phase has been modulated at a phase modulating element. The distance controlling mechanism controls a distance between the phase modulating element and the hologram recording medium. By controlling the distance between the phase modulating element and the hologram recording medium, multiplex recording can be performed on the hologram recording medium.

Abstract: A holographic recording and reconstructing apparatus includes a light source having a variable oscillation wavelength; a temperature sensing unit operable to sense temperature; and a control unit operable to record information about a temperature sensed by the temperature sensing unit on a holographic recording medium during recording, to obtain the information about the temperature from the holographic recording medium and obtain a temperature sensed by the temperature sensing unit during reconstruction, to determine the amount of wavelength shift to counteract the effects of a change in the dimension of the holographic recording medium between recording and reconstruction based on the difference between the temperatures, and to shift the oscillation wavelength of the light source by the determined amount.

Abstract: A holographic recording and reconstructing apparatus includes a laser light source for emitting a laser beam, a beam splitting element for splitting the emitted laser beam into a signal beam and a reference beam, a light modulating element for modulating the signal beam, an optical system for collecting the modulated signal beam and the reference beam onto a reflection hologram recording medium at substantially the same location, a light detection element for detecting a reconstructed light beam from the hologram recording medium, and wavelength shifting means for shifting the wavelength of the laser beam used during reconstruction from the wavelength used during recording.

Abstract: A hologram recording/reproducing device includes a laser light source emitting laser light; a spatial light modulator generating signal light and reference light from the laser light emitted from the laser light source, the signal light and the reference light traveling in a common light path; a first relay lens system including a first shielding plate at a focal position thereof and transmitting the signal light and the reference light generated by the spatial light modulator, the first shielding plate having a pinhole whose size is 1 to 2 times a Nyquist size; a phase modulating element disposed at a conjugate plane of the signal light and the reference light transmitted through the first relay lens system; an objective lens converging the signal light and the reference light transmitted through the phase modulating element on a hologram recording medium; and a light receiving system disposed between the phase modulating element and objective lens and receiving light returning from the hologram recording me

Abstract: A hologram recording apparatus for carrying out holographic recording by emitting a signal beam and a reference beam onto a holographic recording medium includes a laser light source configured to output a pulsed laser beam, a splitter configured to split the laser beam into a signal beam and a reference beam, a spatial light modulator configured to modulate the signal beam or both the signal beam and the reference beam, and a controlling unit configured to control the spatial light modulator to modulate at least one of the signal beam and the reference beam with a totally dark pattern for a predetermined period of time, wherein the predetermined period begins no later than the start of the risetime of a pulse of a laser beam output from the laser light source.

Abstract: A hologram recording apparatus includes a laser light source for emitting laser light, a light splitter for splitting the laser light emitted from the laser light source into a signal beam and a reference beam, a light modulator for modulating the signal beam split by the light splitter, a phase modulator for phase-modulating the reference beam split by the light splitter, an optical system for collecting the signal beam modulated by the light modulator and the reference beam phase-modulated by the phase modulator onto almost the same collecting position on a hologram recording medium, a collecting-position control mechanism for controlling the collecting position along a surface of the hologram recording medium, and a distance control mechanism for controlling the distance between the phase modulator and the hologram recording medium.