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 recording head includes a near-field transducer proximate a media-facing surface of the recording head and a waveguide that overlaps and delivers light to the near-field transducer. The recording head includes subwavelength-sized focusing mirror comprising first and second reflectors disposed on cross track sides of the near-field transducer. Each of the first and second reflectors is spaced apart from the media-facing surface by a distance, D, measured along an axis normal to the media-facing surface.

A recording head includes a near-field transducer proximate a media-facing surface of the recording head and a waveguide that overlaps and delivers light to the near-field transducer. The recording head includes subwavelength-sized focusing mirror comprising first and second reflectors disposed on cross track sides of the near-field transducer. Each of the first and second reflectors is spaced apart from the media-facing surface by a distance, D, measured along an axis normal to the media-facing surface.

A lighting apparatus includes: a light source generating a first color component light; a separation element partially transmitting the first color component light, partially reflecting the first color component light, and transmitting a second color component light different from the first color component light at a certain moment; an illuminant excited by the first color component light transmitted through the separation element to generate the second color component light; and an optical system combining the first color component light made incident on the separation element from the light source and reflected by the separation element with the second color component light made incident on the separation element from the illuminant and transmitted through the separation element. The separation element is configured to have variable transmittance and reflectance with respect to the first color component light.

A lighting apparatus includes: a light source generating a first color component light; a separation element partially transmitting the first color component light, partially reflecting the first color component light, and transmitting a second color component light different from the first color component light at a certain moment; an illuminant excited by the first color component light transmitted through the separation element to generate the second color component light; and an optical system combining the first color component light made incident on the separation element from the light source and reflected by the separation element with the second color component light made incident on the separation element from the illuminant and transmitted through the separation element. The separation element is configured to have variable transmittance and reflectance with respect to the first color component light.

A system includes a plurality of optical identifiers and a reader for the optical identifiers. Each optical identifier has an optical substrate and a volume hologram (e.g., with unique data, such as a code page) in the optical substrate. The reader for the optical identifiers includes an illumination source (e.g., a laser), and a camera. The illumination source is configured to direct light into a selected one of the optical identifiers that has been placed into the reader to produce an image of the associated volume holograms at the camera. The camera is configured to capture the image. The captured image may be stored in a digital format by the system.

A system includes a plurality of optical identifiers and a reader for the optical identifiers. Each optical identifier has an optical substrate and a volume hologram (e.g., with unique data, such as a code page) in the optical substrate. The reader for the optical identifiers includes an illumination source (e.g., a laser), and a camera. The illumination source is configured to direct light into a selected one of the optical identifiers that has been placed into the reader to produce an image of the associated volume holograms at the camera. The camera is configured to capture the image. The captured image may be stored in a digital format by the system.

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 lighting apparatus includes: a light source generating a first color component light; a separation element partially transmitting the first color component light, partially reflecting the first color component light, and transmitting a second color component light different from the first color component light at a certain moment; an illuminant excited by the first color component light transmitted through the separation element to generate the second color component light; and an optical system combining the first color component light made incident on the separation element from the light source and reflected by the separation element with the second color component light made incident on the separation element from the illuminant and transmitted through the separation element. The separation element is configured to have variable transmittance and reflectance with respect to the first color component light.