A method of fabricating an optical element comprises: providing a substrate of a transparent material; applying a plurality of circularly polarised focused femtosecond laser pulses to a volume within the substrate to create substantially spherical nanopores in the volume; and applying at least one and not more than ten non-circularly polarised focused femtosecond laser pulses to the volume to transform the spherical nanopores into oblate spheroidal nanopores.

An optical recording medium includes a first disk, a second disk, and an adhesive layer for bonding the first disk to the second disk. The first disk and the second disk each include a substrate having a first surface and a second surface and having a gradient on an outer peripheral portion of the second surface, two or more information signal layers disposed on the first surface, an intermediate layer disposed between adjacent information signal layers, and a cover layer covering the two or more information signal layers and the intermediate layer. The second surface of the substrate included in the first disk faces the second surface of the substrate included in the second disk with the adhesive interposed therebetween.

An optical recording medium includes a first disk, a second disk, and an adhesive layer for bonding the first disk to the second disk. The first disk and the second disk each include a substrate having a first surface and a second surface and having a gradient on an outer peripheral portion of the second surface, two or more information signal layers disposed on the first surface, an intermediate layer disposed between adjacent information signal layers, and a cover layer covering the two or more information signal layers and the intermediate layer. The second surface of the substrate included in the first disk faces the second surface of the substrate included in the second disk with the adhesive interposed therebetween.

An optical recording medium includes a first disk, a second disk, and an adhesive layer for bonding the first disk to the second disk. The first disk and the second disk each include a substrate having a first surface and a second surface and having a gradient on an outer peripheral portion of the second surface, two or more information signal layers disposed on the first surface, an intermediate layer disposed between adjacent information signal layers, and a cover layer covering the two or more information signal layers and the intermediate layer. The second surface of the substrate included in the first disk faces the second surface of the substrate included in the second disk with the adhesive interposed therebetween.

An optical recording medium includes a first disk, a second disk, and an adhesive layer for bonding the first disk to the second disk. The first disk and the second disk each include a substrate having a first surface and a second surface and having a gradient on an outer peripheral portion of the second surface, two or more information signal layers disposed on the first surface, an intermediate layer disposed between adjacent information signal layers, and a cover layer covering the two or more information signal layers and the intermediate layer. The second surface of the substrate included in the first disk faces the second surface of the substrate included in the second disk with the adhesive interposed therebetween.

The present invention relates to an ultra-thin data carrier for long-term data conservation and to a method of reading out such a data carrier.

The present invention relates to an ultra-thin data carrier for long-term data conservation and to a method of reading out such a data carrier.

An optical disc is formed by bonding a first information recording medium to a second information recording medium. The first information recording medium includes a first substrate having opposed first and second surfaces, at least one dielectric film, at least one recording film, and a cover layer. The second information recording medium includes a second substrate having opposed third and fourth surfaces, at least one dielectric film, at least one recording film, and a cover layer. The second surface of the first substrate is bonded to the fourth surface of the second substrate. At least one of the second surface or the fourth surface includes a depression and a projection. The depression is formed in a thickness direction of the optical disc. The projection is provided inside the depression at a predetermined distance or longer from an outer circumferential edge of the depression in a radial direction of the optical disc.

A method for optically storing and retrieving information is provided that irradiates spin-defect centers in a substrate with red or blue light to change the charge state to form a pattern. This pattern encodes information and long-term data storage. The information is retrieved by irradiating the pattern with red light that causes the pattern to undergo fluorescence.

A method for optically storing and retrieving information is provided that irradiates spin-defect centers in a substrate with red or blue light to change the charge state to form a pattern. This pattern encodes information and long-term data storage. The information is retrieved by irradiating the pattern with red light that causes the pattern to undergo fluorescence.