Abstract: The invention discloses novel dicyanostilbene derivatives bound to a methacrylic moiety that can serve as an active chromophore in a 3-dimensional optical memory, processes for its synthesis and its intermediates.

Abstract: An optical information carrier is presented. The information carrier comprises at least one active layer for recording/reading data in/from as a result of one- or multi-photon interaction; and at least one reference layer structure associated with said at least one active layer. The reference layer structure comprises at least one dielectric material and is different from that of the active layer in its optical properties with respect to one- or multi-photon interaction. Detection of light returned from the reference layer structure allows to control a process of focusing an optical beam onto an addressed recording plane in the active layer during at least one of the recording and reading processes.

Abstract: A method is presented for use in determining a degree of quality of a multi-layer optical data carrier in its at least partially recorded state. Predetermined first data is provided being indicative of a qualified, at least partially recorded multi-layer optical data carrier. This data corresponds to an optical response obtainable from a specific data carrier under predetermined conditions of an optical scan of the rotating data carrier. A data carrier being qualified is scanned by at least one optical beam under said predetermined conditions of the scan, and a first control signal from the data carrier is detected and data indicative of the detected control signal is generated. The so generated data is processed to determine a relation with said predetermined data. The determined relation is used for determining a degree of quality of said scanned data carrier.

Abstract: An optical data carrier is presented. The data carrier comprises at least one recording layer, at least one non-recording layer, and at least one reflective interface. The recording layer is made of a material having a fluorescent property variable on occurrence of multi-photon absorption resulted from an optical beam, and has a thickness for recording therein data in the form of a three-dimensional pattern of spaced-apart recording regions arranged in a plurality of recording planes. The at least one non-recording layer interfaces with the recording layer on, respectively, at least one of upper and lower surfaces of the recording layer The non-recording layer has a fluorescent property different from that of the recording layer, and has a predetermined thickness selected to be equal or larger than a focal depth of an optical system producing the optical beam incidence onto the data carrier. The at least one reflective interface comprises at least one reference layer having a reflecting property.

Abstract: An optical data carrier is presented comprising first and second recordable media located in at least one first portion and at least one second portion of the data carrier, respectively. These first and second recordable media differ from each other in a storage capacity and a data recording rate.

Abstract: An optical data carrier is presented being configured to provide protection for data recordable therein from environmental effects. The optical data carrier comprises recordable media having an outer surface and an inner data volume in which data is to be recorded, said data volume being spaced from said outer surface a certain minimal distance D, a region of the recordable media surrounding the data volume providing at least optical protection for said data volume.

Abstract: Cooperativity between groups within a polymeric photochromic medium provides the basis for enhanced writing effect. The cooperatively may be among photochromic groups being present in a high concentration.

Abstract: An optical data carrier is presented. The data carrier comprises: at least one recording layer composed of a material having a fluorescent property variable on occurrence of multi-photon absorption resulting from an optical beam, said recording layer having a thickness for forming a plurality of recording planes therein; at least one non-recording layer formed on at least one of upper and lower surfaces of said recording layer and differing in fluorescent property from said recording layer; and at least one reference layer having a reflecting surface being an interface between the recording layer and the non-recording layer.

Abstract: The invention discloses novel dicyanostilbene derivatives bound to a methacrylic moiety that can serve as an active chromophore in a 3-dimensional optical memory, processes for its synthesis and its intermediates.

Abstract: An optical information carrier and method and apparatus for securing the carrier are presented. The optical information carrier comprises a recording medium for recording data therein in the form of a first pattern of spaced-apart recorded regions configured to provide a first optical response to incident light, and comprises a pattern of spaced-apart regions configured to respond to incident light by a second optical response pattern. Distribution of the spaced-apart regions forming the second optical response pattern is indicative of an individual and identifiable carrier specific signature.

Abstract: A non-linear optical data carrier is presented. The non-linear optical data carrier is configured for recording therein information defined by a pattern of spaced-apart marks arranged in virtual data layers. The data carrier medium comprises a sub-stance capable of being excited by a first multi-photon interaction to be switched from its first state into a second state, where the first and second states of the substance provide different response signals to a second multi-photon interaction. The substance when in the first and second states have substantially overlapping linear absorption wavelength peaks, and first and second wavelengths involved in the first and second multi-photon processes as well as the response signals wavelengths are outside the linear absorption spectrum peaks of the substance in its first and second states. The basic size of the marks and spaces is larger in the first than in the second layer.

Abstract: A formatter for inscription of marks on to a 3D translucent optical medium to enable recording and retrieval of information from the medium, includes a clamping mechanism to hold the media, and at least one optical unit calibrated to focus at least one diffraction limited spot within the medium at a respective depth therein. At least one light source is optimized for the inscription of marks, and at least one actuator moves the spot relative to the medium.

Abstract: A polymer matrix comprising active chromophoric groups and aromatic compounds selected from phenyls substituted with one or more substituents independently selected from: (i) halogens; (ii) C1-4alkyl esters of carboxylic acid or their amides; (iii) —OR, —SR or —C(?O)R, R being an C1-6alkyl group; (iv) the group —O—(CH2)n—O—C(?O)C(X)?CH2 where X is CH3 or H and n is independently 1-6; or (v) the group —O—C(?O)C(X)?CH2. There is further provided a 3-dimensional optical data storage comprising a photochromic medium, where such a combination facilitates the writing of data in the 3-dimensional optical data storage.

Abstract: A method for data inscription in an acrylic polymer-based photochromic medium is provided in which the photochromic groups are bound to the polymeric matrix. The data is inscribed by irradiating small volume portion with an electromagnetic irradiation that causes a change in state of the photochromic groups from a first to a second state. Said volume portion is heated so as to cause an increase in temperature of said portion at the time of data inscription. The heating may be external or internal. Internal heating makes use of additives that dissipate heat, following their irradiation, to their immediate vicinity. Provided is also a novel acrylic polymer-based photochromic medium comprising said additives.

Abstract: There are provided conjugated systems of formula (I) based on stilbene derivatives serving as improved Donor-Acceptor-Donor compounds and their use in non linear optics including chromophoric optical medium of a 3-dimensional optical memory.

Abstract: A method and apparatus for retrieving information from a three dimensional storage medium uses a three dimensional storage medium having an active medium capable of exhibiting first and second states, a data unit being represented by the ratio between the concentration of the first and second states in a given volume portion of the medium and a data sequence is represented by a sequence of data units. The active medium is irradiated with light as to concentrate light flux through a volume portion of the storage medium so as to generate in the volume portion a detectable non-linear optical response characteristic of the concentration ratio, which is detected and used for tracking.

Abstract: Disclosed is a swing type optical disc drive. The drive includes a disc rotating on a disc support and a swing arm pivoted at one of its ends and having a distal end communicating with an encoder. The pivot point and a point on distal end define a swing axis of the arm. The disc further includes an optical system mounted on the arm such that optical axis of the system is parallel with the swing axis and both axes lie in the same plane. A cam actuator imparts a swinging motion to the arm. The swinging motion of the arm positions the plane with the optical axis and the arm axes such that the plane is always tangent to a reading/recording track of the disc.

Abstract: The present invention is directed to a three-dimensional memory apparatus for storing information in a volume comprising of an active medium. The active medium is capable of changing from a first to a second isomeric form as a response to radiation of a light beam having an energy substantially equal to a first threshold energy. The concentration ratio between a first and a second isomeric form in any given volume portion represents a data unit. The active medium in the memory apparatus comprises of diarylalkene derivatives, triene derivatives, polyene derivatives or a mixture thereof. The invention is further directed to means for reading the data units from the isomeric states of the active medium in different portions of said active medium where the two isomeric forms have a substantially different absorption coefficient for absorbing energy of a second threshold energy. Reading may also be carried out by measuring the scattering pattern of the two isomeric forms.

Abstract: A method and apparatus for retrieving information from a three dimensional storage medium uses a three dimensional storage medium having an active medium capable of exhibiting first and second states, a data unit being represented by the ratio between the concentration of the first and second states in a given volume portion of the medium and a data sequence is represented by a sequence of data units. The active medium is irradiated with light as to concentrate light flux through a volume portion of the storage medium so as to generate in the volume portion a detectable non-linear optical response characteristic of the concentration ratio, which is detected and used for tracking.

Abstract: A three dimensional optical information carrier is presented. The information carrier comprises formatting marks disposed on the nodes of a three dimensional lattice formed by the intersection of equiangular spaced radial planes, equidistantly spaced cylindrical spiral tracks and virtual recording planes.