A holographic recording medium composition contains an isocyanate group-containing compound (component (a-1)), an isocyanate-reactive functional group-containing compound (component (b-1)), a polymerizable monomer (component (c-1)), a photopolymerization initiator (component (d-1)), and a stable nitroxyl radical group-containing compound (component (e-1)). A ratio of the total weight of a propylene glycol unit and a tetramethylene glycol unit that are contained in the component (b-1) to the total weight of the component (a-1) and the component (b-1) is 30% or less.

A holographic recording medium composition contains an isocyanate group-containing compound (component (a-1)), an isocyanate-reactive functional group-containing compound (component (b-1)), a polymerizable monomer (component (c-1)), a photopolymerization initiator (component (d-1)), and a stable nitroxyl radical group-containing compound (component (e-1)). A ratio of the total weight of a propylene glycol unit and a tetramethylene glycol unit that are contained in the component (b-1) to the total weight of the component (a-1) and the component (b-1) is 30% or less.

To provide a hologram recording composition capable of further improving diffraction characteristics and the transparency of a hologram.

The present technology provides a hologram recording composition containing at least a chromic dye whose decolorized body has a structure containing a primary and/or secondary amino group, an epoxy monomer, and a polymerization initiator. The present technology also provides a hologram recording medium including a photosensitive layer containing at least a chromic dye whose decolorized body has a structure containing a primary and/or secondary amino group, an epoxy monomer, and a polymerization initiator. Furthermore, the present technology also provides a hologram optical element using the hologram recording medium. Moreover, the present technology also provides an optical device and an optical component using the hologram optical element. The present technology also provides a method for forming a hologram diffraction grating, the method including causing the hologram recording medium to react selectively by an electromagnetic beam having a spatially modulated amplitude.

A holographic recording medium composition contains an isocyanate group-containing compound (component (a-1)), an isocyanate-reactive functional group-containing compound (component (b-1)), a polymerizable monomer (component (c-1)), a photopolymerization initiator (component (d-1)), and a stable nitroxyl radical group-containing compound (component (e-1)). A ratio of the total weight of a propylene glycol unit and a tetramethylene glycol unit that are contained in the component (b-1) to the total weight of the component (a-1) and the component (b-1) is 30% or less.

A holographic recording medium composition contains an isocyanate group-containing compound (component (a-1)), an isocyanate-reactive functional group-containing compound (component (b-1)), a polymerizable monomer (component (c-1)), a photopolymerization initiator (component (d-1)), and a stable nitroxyl radical group-containing compound (component (e-1)). A ratio of the total weight of a propylene glycol unit and a tetramethylene glycol unit that are contained in the component (b-1) to the total weight of the component (a-1) and the component (b-1) is 30% or less.

Infrared dyes having an infrared absorption maximum above 1130 nm with minor colouration in the visual spectrum. The infrared dyes are especially useful for producing multicolour laser marked security documents having reduced background coloration and enhanced colour gamut.