Abstract: The invention relates generally to optical data storage media, and more specifically, to holographic storage media. In one embodiment, an optical storage medium composition includes a polymer matrix. Disposed within the polymer matrix is a reactant capable of undergoing a modification that alters the refractive index of the composition upon receiving an energy transfer from an excited sensitizer. A non-linear sensitizer is also disposed within the polymer matrix, and the sensitizer includes a metal-substituted subphthalocyanine (M-sub-PC) reverse saturable absorber configured to become excited upon exposure to light beyond an intensity threshold at approximately 405 nm and configured to transfer energy to the reactant.

Abstract: An apparatus and method for recording a micro-hologram are provided. The micro-hologram recording apparatus includes a first light source configured to emit a first light, the first light being coherent, a first optical system configured to divide the first light into a signal beam and a reference beam, and supply the signal beam and the reference beam to a location on a hologram recording medium, a second light source configured to emit a second light, the second light being incoherent and not interfering with the signal beam and the reference beam, and a second optical system configured to supply the second light to the same location as the signal beam and the reference beam on the hologram recording medium.

Abstract: Optical data storage media for bit-wise recording of a microhologram using an incident radiation at a wavelength of about 405 nm are provided. The optical storage medium includes (a) a non-photopolymer polymer matrix; (b) a non-linear sensitizer comprising a phenylethynyl platinum complex, wherein the non-linear sensitizer is capable of triplet-triplet energy transfer from an upper triplet state (Tn) of the non-linear sensitizer to a lower triplet state (T1) of a reactant, wherein “n” is an integer greater than 1; and (c) a reactant capable of undergoing a chemical change upon the triplet-triplet energy transfer from the non-linear sensitizer, thereby causing a refractive index change in the medium to record the microhologram.

Abstract: An information storage device includes an information recording medium, at least a single light source that emits laser light, an illuminating unit that illuminates substantially the same position of the information recording medium with two light rays generated from the laser light, in different directions, a light detecting unit that detects reflection light of the two light rays reflected from the information recording medium and outputs a detection signal, an operation unit that calculates position error information of the information recording medium based on the detection signal; and, a driving device that changes the position of the information recording medium based on the position error information.

Abstract: A holographic memory apparatus comprises first phase modulation means that adds phase information to each pixel of a signal beam to generate page data at recording time; oscillator light generation means that generates an oscillator light that is superimposed on, and interferes with, a diffracted light from a holographic recording medium at reproduction time; second phase modulation means that adds phase information to the oscillator light; and light detection means that detects an interference light generated by superimposing the oscillator light and the diffracted light from the holographic recording medium.

Abstract: An apparatus for reading from a multilayer holographic storage medium with a coaxial arrangement of a reference beam and a reconstructed object beam is described. The apparatus has an objective lens for focusing the reference beam into the multilayer holographic storage medium such that the reference beam has a focal point behind or in front of a reflective layer of the multilayer holographic storage medium, wherein a distance between the objective lens and the multilayer holographic storage medium is set in accordance with an addressed layer of the multilayer holographic storage medium, and an imaging system with a fixed lens of focal length f and a movable lens of focal length f for re-collimating a reconstructed object beam, wherein for a specific position of the movable lens the imaging system assumes a 4f configuration.

Abstract: A recording signal beam and a recording reference beam are irradiated onto a first surface of a holographic recording medium to write an information as an interference pattern therein. Next, a reflective layer is provided on a second surface opposite to the first surface of the holographic recording medium such that the reflective layer is adhered with the second surface, and a reproducing reference beam is irradiated onto the first surface of the holographic recording medium so as to read a signal beam which is reflected at the reflective layer and reproduced from the holographic recording medium.

Abstract: A data page for use in a holographic data storage system, and to a method and an apparatus for writing to holographic storage media using such a data page are described. The data page has dark zones for each boundary between phase blocks of a phase mask of the holographic data storage system, which consist of switched-off pixels that are not used for encoding data, and which coincide with the boundaries between the phase blocks.

Abstract: A two-dimensional demodulation method for reproducing a data page by means of decision feedback Viterbi detection processing from a recording medium on which a data page has been recorded as a set of a plurality of two-dimensional modulation pattern symbols each of which comprises a plurality of pixels, and which have been modulated two-dimensionally, the method comprising: a step of determining a value of pixel deviation in a reproduction image obtained by receiving light from the recording medium on an image sensor; a step of splitting an output signal of the image sensor which indicates the reproduction image of the light received from the recording medium into signal symbol data by division into blocks in accordance with the two-dimensional modulation pattern symbols; and a step of carrying out decision feedback Viterbi detection for each signal symbol data in accordance with the pixel deviation value.

Abstract: A marker selection method includes: a marker generation step for generating a marker defining a position reference when recording data according to the modulation rule of the hologram recording/reproduction; a calculation step for calculating a correlation value indicating the correlation between a template image indicating a maker and each of a first verification image containing the marker shifted by a predetermined pixel and a second verification image containing data; and a selection step for selecting such a marker that the peak of the correlation value in the first verification image becomes greater than the peak of the correlation value in the second verification image. The selected marker is used as marker data in a marker generator in a recording processing circuit during recoding and as template data of the template matching processing circuit in the reproduction processing circuit during reproduction.