A non-linear optical material is represented by formula (1) below. In formula (1), L.sup.1 to L.sup.3 are each independently represented by formula (2) or (3) below.

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A recording material includes a dye-bonded polymer compound which contains a polymer compound to which a one-photon absorption dye is bonded, and a glass transition temperature of the recording material is higher than 200° C. An optical information recording medium includes a recording layer and an intermediate layer adjacent to the recording layer, and the recording layer contains the above-described recording material.

A recording material includes a dye-bonded polymer compound which contains a polymer compound to which a one-photon absorption dye is bonded, and a glass transition temperature of the recording material is higher than 200° C. An optical information recording medium includes a recording layer and an intermediate layer adjacent to the recording layer, and the recording layer contains the above-described recording material.

A reversible recording medium according to an embodiment of the present disclosure is a reversible recording medium that includes recording layers and heat-insulating layers that are alternately stacked, in which the recording layers each include a reversible heat-sensitive color developing composition and a first light-heat converting agent. In this reversible recording medium, the recording layers are different from each other in a developing color of their respective reversible heat-sensitive color developing compositions and are different from each other in an absorption wavelength of their respective first light-heat converting agents. This reversible recording medium further includes a heat-generating layer that includes a second light-heat converting agent having an absorption wavelength that is different from the absorption wavelength of the first light-heat converting agent included in each of the recording layers.

A data protector according to an embodiment of the present disclosure includes: a data layer configured to record confidential information as a visible image; and one or a plurality of cover layers disposed at least one of above or below the data layer and configured to transition between a color-developed state and a decolored state in a visible wavelength region.

In a drawing method according to an embodiment of the present disclosure, when performing drawing on a thermal recording medium that includes, above a recording layer, a light-transmitting member having an uneven shape in a plane, an optical compensator having one surface and another surface is provided on the light-transmitting member to cause the one surface and the light-transmitting member to face each other, and the thermal recording medium is irradiated with a laser beam via the optical compensator. The one surface of the optical compensator has a shape that fits the uneven shape of the light-transmitting member, and the other surface is flat and opposed to the one surface.

To provide a hologram recording composition that can further improve diffraction characteristics and transparency of a hologram.

The present technology provides a hologram recording composition containing a heteropoly acid, a photopolymerizable monomer, a photopolymerization initiator, and a sensitizing dye having absorption in a visible light region in the presence of an acid. The present technology also provides a hologram recording medium including at least a photocurable resin layer containing a heteropoly acid, a photopolymerizable monomer, a photopolymerization initiator, and a sensitizing dye having absorption in a visible light region in the presence of an acid. Furthermore, the present technology also provides a diffraction optical element using the hologram recording medium. Moreover, the present technology also provides an optical device, an optical component, and an image display device using the diffraction optical element.

To provide a hologram recording composition that can further improve diffraction characteristics and transparency of a hologram.

The present technology provides a hologram recording composition containing a heteropoly acid, a photopolymerizable monomer, a photopolymerization initiator, and a sensitizing dye having absorption in a visible light region in the presence of an acid. The present technology also provides a hologram recording medium including at least a photocurable resin layer containing a heteropoly acid, a photopolymerizable monomer, a photopolymerization initiator, and a sensitizing dye having absorption in a visible light region in the presence of an acid. Furthermore, the present technology also provides a diffraction optical element using the hologram recording medium. Moreover, the present technology also provides an optical device, an optical component, and an image display device using the diffraction optical element.

An information medium according to an embodiment of the present disclosure includes two or more data layers provided on a support base. The two or more data layers have two or more pieces of visible information recorded on the two or more data layers. The two or more pieces of visible information are obtained by decomposing two-dimensional visible information and thereby allowing synthesis of the two or more pieces of visible information to result in the two-dimensional visible information.

To provide a photosensitive composition capable of further improving diffraction characteristics.

The present technology provides a photosensitive composition including: at least a compound represented by the following general formula (1); a binder resin; and a photoinitiator.

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In the general formula (1), X.sup.1 represents an oxygen atom, a nitrogen atom, a phosphorus atom, a caron atom, or a silicon atom.

Y.sup.1 and Y.sup.2 each represent a benzene ring or a naphthalene ring, and both Y.sup.1 and Y.sup.2 do not represent benzene rings.

R.sup.1 to R.sup.3 each represent a hydrogen or a substituent group represented by *—Z.sup.1(R.sup.4).sub.d (* represents a bonding site).

Z.sup.1 represents a single bond, a saturated hydrocarbon group having a valence of 2 or higher, or an unsaturated hydrocarbon group having a valence of 2 or higher, and the saturated hydrocarbon group or the unsaturated hydrocarbon group may have an ether bond and/or a thioether bond.

R.sup.4 represents a hydrogen or a polymerizable substituent group.