Abstract: The present invention relates to a method for performing pre-exposure and curing of a photo-sensitive material for optical data storage, in particular for holographic data storage, and to an apparatus for writing to optical storage media using such method. According to the invention, for pre-exposure and/or curing of an optical storage medium the optical storage medium is illuminated by a coherent light beam emitted by a light source, which is also used for data recording. Pre-exposure and/or curing is performed in one or more exposure steps, in which the coherent light beam carries a data pattern, the exposure dose for each exposure step being smaller than a minimum dose such that the diffraction efficiency of the recorded data pattern is too low to distinguish data from noise.

Abstract: The invention relates to a compact optical pickup for a micro optical drive, and to a micro optical drive using this compact optical pickup. According to the invention a pickup for optical recording media includes a light source for generating a light beam for reading from and/or writing to an optical recording medium, a flexible arm serving as a focus actuator, an objective lens situated on the flexible arm for focusing the light beam onto the optical recording medium, an optical bench for directing the light beam towards the optical recording medium one or more detectors for detecting the light beam reflected by the optical recording medium, and a mirror, which is arranged inclined with respect to a transparent block of the optical bench, for directing the light beam reflected by the optical recording medium towards a first detector.

Abstract: The optical storage medium comprises a substrate layer, a data layer with a mark/space structure arranged in tracks on the substrate layer, and a cover layer. One track comprises positive marks and a neighboring track comprises negative marks. The tracks are arranged in particular as spirals wherein one spiral contains a track with only positive marks and a neighboring spiral contains a track with only negative marks. The positive marks of a track and correspondingly the negative marks of a track are separated each by spaces. The optical storage medium is particularly a read-only optical disc and comprises a mask layer with a super resolution near field structure, wherein the tracks of the data layer are arranged as two spirals, one spiral consisting of positive marks only and the other spiral consisting of negative marks only.

Abstract: A high data density optical recording medium, a method and an apparatus for reading from such an optical recording medium, and a method for mastering such an optical recording medium are proposed. For achieving a high data density the optical recording medium has marks that have a tip and are covered by a material that generates a detectable effect under the influence of high electric fields.

Abstract: An apparatus for reading and writing holograms from and to a holographic storage medium is described, which uses an object beam and a reference beam both having a first coherence length and being guided along separate optical branches of an optical setup to be imaged to the holographic storage medium. The apparatus comprises means for reducing the coherence length of the reference beam to a second coherence length for reading out a hologram from the holographic storage medium, wherein the second coherence length is shorter than the first coherence length.

Abstract: The present invention relates to a method for checking the quality of a recording on a disk intended to be read with a first wavelength and intended to be recorded with a second wavelength, directly with the second wavelength used by the recording system. According to the invention, the method uses a modified jitter definition when a jitter value of recorded information is measured using light of the first wavelength. A special equalizer takes account of a required asymmetry.

Abstract: The apparatus comprising a pickup for reading data from or writing data to an optical storage medium, wherein the pickup comprises a laser providing a laser beam, an objective lens for focusing the laser beam onto the optical storage medium, a first detector and a beam splitter arranged between the laser and the objective lens for guiding light reflected from the optical storage medium onto the first detector. A selecting means, arranged in front of the beam splitter, with regard to the reflected light from the optical storage medium, is provided for guiding reflected light passing through an outer section of the objective lens onto a second detector. The light guided onto the first detector is utilized for providing a tracking error signal and the light guided onto the second detector is utilized for providing a data signal.

Abstract: A holographic storage system having an improved data page quality is described. The holographic storage system includes a special optical filter or a special light source for emphasizing the high frequency components of a reference beam and/or an object beam. This is achieved by an optical filter arranged in a Fourier plane, which has a higher attenuation at the center than at the edge. Alternatively, an adapted light source for generating the reference beam and/or the object beam is arranged in a Fourier plane. The light beam emitted by the light source has a higher intensity close to the edge than at is the center.

Abstract: The optical storage medium, in particular a read-only optical disc, comprises a substrate layer, a read only data layer comprising a pit structure and being arranged on the substrate layer, a mask layer comprising nanoparticles for providing a super resolution near field effect, and a dielectric layer arranged between the data layer and the mask layer. The dielectric layer has a thickness, which changes in dependency of the pit structure and is for example a plastic layer having a completely flat surface for providing a uniform arrangement of the nanoparticles. For the manufacturing of a respective optical storage medium, the dielectric layer is arranged on the data layer advantageously by means of spin coating.

Abstract: The optical recording medium has a recording layer sensitive for recording at a first wavelength and sensitive for reading at a second wavelength, the recording layer having a groove structure, wherein at the first wavelength the groove structure has a diffraction efficiency into a first diffraction order sufficiently large to generate a push-pull signal, and at the second wavelength it has a diffraction efficiency into a first diffraciton order close to zero. The optical pickup for recording on an optical recording medium intended to be read with a second wavelength and a second numerical aperture is characterized in that it has a light source for generating a light beam at a first wavelength and a numerical aperture given by the second numerical aperture multiplied with a ration of the first wavelength and the second wavelength.

Abstract: The present invention relates to a format of a recordable optical recording medium, which is designed in such a way that it can be read by any standard player and recorder. The optical recording medium has a recording layer with a structure of lands and grooves, which generates a strong push-pull signal in an area of the recording layer without recorded marks and a small push-pull signal in an area of the recording layer with recorded marks.

Abstract: The present invention relates to a method and a device for determining spherical aberration occurring during reading from and/or writing to optical recording media. According to the invention, a method for determining spherical aberration includes the steps of: splitting the light beam into at least two partial light beams with a volume hologram having stored wavefront patterns with various degrees of spherical aberration; focusing the partial light beams onto respective detectors, whereby at least one signal generated by the detectors depends on the positions of the respective partial light beam; and determining the spherical aberration using the signals generated by the detectors.

Abstract: Holographic storage system with multiple reference beams An apparatus for reading from and/or writing to holographic storage media is described, and more specifically an apparatus for reading from and/or writing to holographic storage media with two or more reference beams that overlap inside the holographic storage medium for reading and/or writing a single hologram. The two or more reference beams are mutually incoherent during reading and/or writing.

Abstract: A reflection type collinear holographic storage system is described, in which an improved overlap between an object beam and a reference beam is achieved. The collinear holographic storage system has a spatial light modulator for imprinting a data page on an object beam, which is located in the beam path of a portion of a reference beam transmitted through a holographic storage medium, whereby the object beam is generated by imprinting a data page onto the transmitted reference beam. The diameter of the reference beam inside the holographic storage medium is matched to the diameter of the object beam.

Abstract: The present invention relates to a method and a device for determining spherical aberration occurring during reading from and/or writing to optical recording media. According to the invention, a method for determining spherical aberration includes the steps of: splitting the light beam into at least two partial light beams with a volume hologram having stored wavefront patterns with various degrees of spherical aberration; focusing the partial light beams onto respective detectors whereby at least one signal generated by the detectors depends on the positions of the respective partial light beam; and determining the spherical aberration using the signals generated by the detectors.

Abstract: In order, in the case of a holographic system, in particular for holographic data storage, comprising a radiation source for emission of a radiation an objective lens, a signal evaluation means, a detector and an optical data storage medium, the optical data storage medium having at least one data carrier layer and at least one beam-reflecting layer, to provide a solution which forms a small, compact and robust unit, in the case of which the signal beam crosses the reference beam only once, which avoids the use of optical beam splitters and requires a minimal alignment outlay, it is proposed that the objective lens has a plurality of sections, at least two beams that run parallel passing through the objective lens in a respective section and the at least two beams focusing at respectively separate locations on a plane in the optical data storage medium, at least one beam reflected in the optical data storage medium passing through the objective lens again in a respective further section.

Abstract: The invention relates to an optical pickup for an optical recording medium, an electrically controlled diffraction grating suitable for use in such a pickup, and to an apparatus for reading from and/or writing to optical recording media using such an optical pickup or diffraction grating. According to the invention, an optical pickup for optical recording media having two or more data tracks, with a light source for emitting a light beam for reading from and/or writing to an optical recording medium, includes an electrically controlled diffraction grating, which is switchable between at least two states for generating one or more light beams from the light beam emitted by the light source for reading from and/or writing to one or more of the data tracks.

Abstract: The invention relates to a compact optical pickup for a micro optical drive, and to a micro optical drive using this compact optical pickup. According to the invention a pickup for optical recording media includes a light source for generating a light beam for reading from and/or writing to an optical recording medium, a flexible arm serving as a focus actuator, an objective lens situated on the flexible arm for focusing the light beam onto the optical recording medium, an optical bench for directing the light beam towards the optical recording medium, one or more detectors for detecting the light beam reflected by the optical recording medium, and a mirror, which is arranged inclined with respect to a transparent block of the optical bench, for directing the light beam reflected by the optical recording medium towards a first detector.

Abstract: The shaping of pixels of a data page for holographic recording, a holographic recording medium including data pages with shaped pixels, and apparatuses for writing to or reading from such holographic recording media are disclosed. A device for modulating a light beam to generate a data page having a plurality of pixels applies a spatially varying pixel size over the data page. An apparatus for writing to holographic recording media includes such a device for modulating a light beam, while an apparatus for reading from holographic recording media includes an adapted detector for detecting the data page having a plurality of pixels with a spatially varying pixel size.

Abstract: A system and method for watermarking a film includes a light source array including one or more light sources having light directed toward a film to be watermarked. A control mechanism is configured to synchronize a position of the film with the light sources such that the light sources are activated to record a watermark on the film to identify an aspect of the film, wherein the watermark includes a plurality of spots aligned transversely to a direction of film motion during printing of the film.