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.

Techniques disclosed herein relate to modifying refractive index modulation in a holographic optical element, such as a holographic grating. According to certain embodiments, a holographic optical element or apodized grating includes a polymer layer comprising a first region characterized by a first refractive index and a second region characterized by a second refractive index. The holographic optical element or apodized grating includes a plurality of nanoparticles dispersed in the polymer layer. The nanoparticles have a higher concentration in either the first region or the second region. In some embodiments, the nanoparticles may be configured to increase the refractive index modulation. In some embodiments, the nanoparticles may be configured to apodize the grating by decreasing the refractive index modulation proximate to sides of the grating. The refractive index may be modulated by applying a monomer reservoir buffer layer to the polymer layer, either before or after hologram fabrication.

A polarization diffraction element comprising a film including a liquid crystalline material having photosensitivity, the film having at least one hologram recorded therein, and thereby having a property as a fork-shaped polarization grating having an anisotropic structure in which an optical axis continuously rotates toward a direction of a grating vector.

The present disclosure relates to a photopolymer composition including a polymer matrix or a precursor thereof having a predetermined chemical structure; a photoreactive monomer; and a photoinitiator, a hologram recording medium, an optical element and a holographic recording method using the same.

A holographic optical apparatus includes a beam splitting component, a transmission assembly, a focal length modulation component and an optical element. The beam splitting component splits received light into reference light and signal light that are coherent light, and outputs the reference light and the signal light. The focal length modulation component includes a plurality of local length modulation regions with different focal lengths. The optical element includes a recording medium layer with a plurality of recording regions, and each recording region is located in a light-exit path of a focal length modulation region. The transmission assembly is disposed in a light-exit path of the beam splitting component, transmit the reference light to the plurality of recording regions and transmit the signal light to the plurality of focal length modulation regions.

Provided is a photopolymer composition for hologram recording comprising: a polymer matrix or a precursor thereof; a dye including a compound of the following Chemical Formula 1; a photoreactive monomer; and a photoinitiator,

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An optical device includes a first polarization selective reflector positioned relative to a spatial light modulator; and a first reflective assembly positioned relative to the first polarization selective reflector so that the first polarization selective reflector receives first light from the spatial light modulator and directs at least a portion of the first light having a first polarization toward the first reflective assembly as second light. The first reflective assembly receives the second light from the first polarization selective reflector and directs at least a portion of the second light toward the first polarization selective reflector as third light having a second polarization. The second polarization is distinct from the first polarization.

An optical device includes a first polarization selective reflector positioned in a first orientation so that the first polarization selective reflector: receives first light in a first direction; redirects a first portion, of the first light, having a first polarization to a second direction that is non-parallel to the first direction; and receives second light in a third direction and transmit a first portion, of the second light. A second polarization selective reflector positioned in a second orientation non-parallel to the first orientation, and adjacent to the first polarization selective reflector so that the second polarization selective reflector: receives third light in a fourth direction; redirects a first portion, of the third light, having the first polarization to a fifth direction that is non-parallel to the fourth direction; and receives fourth light in a sixth direction and transmit a first portion, of the fourth light having the second polarization.

An optical device includes a first polarization selective reflector; a second polarization selective reflector positioned relative to the first polarization selective reflector so that the first polarization selective reflector directs first light toward the second polarization selective reflector and the second polarization selective reflector directs at least a portion of the first light toward the first polarization selective reflector as second light. The optical device includes a first reflector positioned relative to the first polarization selective reflector so that the first polarization selective reflector directs at least a portion of the second light received from the second polarization selective reflector toward the first reflector as third light and the first reflector directs at least a portion of third light toward the first polarization selective reflector.

An optical device includes a first polarization selective reflector; a second polarization selective reflector positioned relative to the first polarization selective reflector so that the first polarization selective reflector directs first light having a first nonplanar polarization toward the second polarization selective reflector and the second polarization selective reflector directs at least a portion of the first light toward the first polarization selective reflector as second light. The optical device includes a first reflector positioned relative to the first polarization selective reflector so that the first polarization selective reflector directs at least a portion of the second light having a second nonplanar polarization toward the first reflector as third light.