A record playback apparatus of the present disclosure includes a plurality of optical pickups that records information on a recording medium or plays back information from the recording medium; a single transport mechanism that transports the plurality of optical pickups together; and a transport control circuit that drives the single transport mechanism so that, when the single transport mechanism is driven to transport the plurality of optical pickups to respective target positions on the recording medium, absolute value of a maximum value of transport errors of the plurality of optical pickups with respect to the respective target positions becomes substantially equal to absolute value of a minimum value of transport errors of the plurality of optical pickups with respect to the respective target positions.

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.

A reproduction apparatus dividing a cross section of superposed light into a plurality of regions in a tangential and/or radial direction includes: an optical system configured to generate each of a first set of signal light and reference light having a phase difference of approximately 0°, a second set of signal light and reference light having a phase difference of approximately 180°, a third set of signal light and reference light having a phase difference of approximately 90°, and a fourth set of signal light and reference light having a phase difference of approximately 270°, using a plurality of superposed light beams corresponding to the divided regions; an optical receiver configured to output signals corresponding to the sets of the signal light and the reference light; and a circuit configured to compute signals as differences between the signals, and obtain a reproduction signal by computation from the computed signals.

A reproduction apparatus dividing a cross section of superposed light into a plurality of regions in a tangential and/or radial direction includes: an optical system configured to generate each of a first set of signal light and reference light having a phase difference of approximately 0°, a second set of signal light and reference light having a phase difference of approximately 180°, a third set of signal light and reference light having a phase difference of approximately 90°, and a fourth set of signal light and reference light having a phase difference of approximately 270°, using a plurality of superposed light beams corresponding to the divided regions; an optical receiver configured to output signals corresponding to the sets of the signal light and the reference light; and a circuit configured to compute signals as differences between the signals, and obtain a reproduction signal by computation from the computed signals.

A reproduction apparatus dividing a cross section of superposed light into a plurality of regions in a tangential and/or radial direction includes: an optical system configured to generate each of a first set of signal light and reference light having a phase difference of approximately 0°, a second set of signal light and reference light having a phase difference of approximately 180°, a third set of signal light and reference light having a phase difference of approximately 90°, and a fourth set of signal light and reference light having a phase difference of approximately 270°, using a plurality of superposed light beams corresponding to the divided regions; an optical receiver configured to output signals corresponding to the sets of the signal light and the reference light; and a circuit configured to compute signals as differences between the signals, and obtain a reproduction signal by computation from the computed signals.

A reproduction apparatus dividing a cross section of superposed light into a plurality of regions in a tangential and/or radial direction includes: an optical system configured to generate each of a first set of signal light and reference light having a phase difference of approximately 0°, a second set of signal light and reference light having a phase difference of approximately 180°, a third set of signal light and reference light having a phase difference of approximately 90°, and a fourth set of signal light and reference light having a phase difference of approximately 270°, using a plurality of superposed light beams corresponding to the divided regions; an optical receiver configured to output signals corresponding to the sets of the signal light and the reference light; and a circuit configured to compute signals as differences between the signals, and obtain a reproduction signal by computation from the computed signals.

3D optical data storage refers to forms of optical data storage in which information can be recorded and/or read with 3D resolution. 3D optical media are generally limited in areal density by the diffraction limit of laser light used to read and/or write data to and/or from the optical media. It is thus advantageous to find ways to store data on 3D optical media with a spot size below the diffraction limit of an associated laser reader to further increase areal density of the optical media. A hybrid approach that utilizes plasmon technology to access a surface layer of the 3D optical media with an extremely small spot size and photon technology to access interior layers of the 3D optical media with a larger spot size may substantially increase overall data density of the 3D optical media.

3D optical data storage refers to forms of optical data storage in which information can be recorded and/or read with 3D resolution. 3D optical media are generally limited in areal density by the diffraction limit of laser light used to read and/or write data to and/or from the optical media. It is thus advantageous to find ways to store data on 3D optical media with a spot size below the diffraction limit of an associated laser reader to further increase areal density of the optical media. A hybrid approach that utilizes plasmon technology to access a surface layer of the 3D optical media with an extremely small spot size and photon technology to access interior layers of the 3D optical media with a larger spot size may substantially increase overall data density of the 3D optical media.

An apparatus comprises a photodetector (PD) that irradiates a disk with laser light and outputs a signal based on a reflected light from the disk, a front monitor that outputs a reference signal based on an emitted light of a laser diode, and a data detection processing unit to which an output signal of the PD is input to generate a reproduction signal. The data detection processing unit includes a reproduction signal adaptive equalizer that outputs an equalization signal by adaptive equalization processing based on the PD output signal, and a laser noise adaptive equalizer that outputs the equalization signal by the adaptive equalization processing based on a laser noise signal, and generates the reproduction signal in which the laser noise is reduced on the basis of an arithmetic operation result of the output of the reproduction signal adaptive equalizer and the output of the laser noise adaptive equalizer.