A device includes a substrate, an alignment structure disposed on the substrate, and a layer of a birefringent medium disposed on the alignment structure. The birefringent medium has an extraordinary refractive index, an ordinary refractive index different from the extraordinary refractive index, and an intermediate refractive index between the extraordinary refractive index and the ordinary refractive index. Molecules of the birefringent medium are configured to form helical structures having a helical axis. The layer is configured with an out-of-plane principal refractive index along the helical axis, and two equal in-plane principal refractive indices within a plane perpendicular to the helical axis. The out-of-plane principal refractive index is equal to the intermediate refractive index, and is substantially the same as the two equal in-plane principal refractive indices.

A polarization diffraction element comprising including 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 invention relates to a method for producing a holographic optical element by providing a recording stack comprising at least one recording element laminated on at least one supporting element, irradiating at least a part of the recording stack with at least one recording beam in an irradiating step, wherein during the irradiating step, the recording stack bends, providing a bending deviation threshold for the recording stack, and adjusting at least one first process parameter such that an expected maximum bending deviation of the recording stack does not exceed the bending deviation threshold, wherein the at least one first process parameter influences the bending behaviour of the recording stack during the irradiating step.

Systems, devices, and methods for holographic optical elements are described. A holographic optical element includes a first layer of holographic material and a second layer of holographic material. The first layer of holographic material includes a first hologram responsive to light in a first waveband and a second hologram responsive to light in a second waveband. The second layer of holographic material includes a third hologram responsive to light in a third waveband and may include a fourth hologram responsive to light in a fourth waveband. The first, second, third, and fourth wavebands are distinct and may comprise light of red, blue, green, and infrared wavelengths, respectively. Distribution of the three or four holograms on two layers of holographic material allows each hologram to have an index modulation of greater than 0.016, a diffraction efficiency of greater than 15%, and an angular bandwidth of greater than 12.

Systems, devices, and methods for holographic optical elements are described. A holographic optical element includes a first layer of holographic material and a second layer of holographic material. The first layer of holographic material includes a first hologram responsive to light in a first waveband and a second hologram responsive to light in a second waveband. The second layer of holographic material includes a third hologram responsive to light in a third waveband and may include a fourth hologram responsive to light in a fourth waveband. The first, second, third, and fourth wavebands are distinct and may comprise light of red, blue, green, and infrared wavelengths, respectively. Distribution of the three or four holograms on two layers of holographic material allows each hologram to have an index modulation of greater than 0.016, a diffraction efficiency of greater than 15%, and an angular bandwidth of greater than 12.

Systems, devices, and methods for holographic optical elements are described. A holographic optical element includes a first layer of holographic material and a second layer of holographic material. The first layer of holographic material includes a first hologram responsive to light in a first waveband and a second hologram responsive to light in a second waveband. The second layer of holographic material includes a third hologram responsive to light in a third waveband and may include a fourth hologram responsive to light in a fourth waveband. The first, second, third, and fourth wavebands are distinct and may comprise light of red, blue, green, and infrared wavelengths, respectively. Distribution of the three or four holograms on two layers of holographic material allows each hologram to have an index modulation of greater than 0.016, a diffraction efficiency of greater than 15%, and an angular bandwidth of greater than 12.

A composition for a hologram recording material includes a binder precursor containing a compound having a structure represented by formula A below, a polymerizable monomer and a photopolymerization initiator.

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In the formula A, R.sup.1 to R.sup.3 each represent a hydrogen atom or a substituent, E represents a divalent electron attracting group, a wavy line portion represents a bonding site with another structure, and when E is C(O)O, R.sup.3 is not an alkyl group.

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.

The invention relates to a method for producing a holographic optical element by providing a recording stack comprising at least one recording element laminated on at least one supporting element, irradiating at least a part of the recording stack with at least one recording beam in an irradiating step, wherein during the irradiating step, the recording stack bends, providing a bending deviation threshold for the recording stack, and adjusting at least one first process parameter such that an expected maximum bending deviation of the recording stack does not exceed the bending deviation threshold, wherein the at least one first process parameter influences the bending behavior of the recording stack during the irradiating step.

A display device includes an optical sensor configured to image a user eye, an image source configured to provide image light, a holographic film including a plurality of holograms, and a controller. Each hologram is recorded with a same reference beam but recorded differently so as to differently diffract image light received from the light source. The controller is configured to determine, via the optical sensor, a position of the user eye, and adjust, based on the determined position of the user eye, a state of the holographic film such that a particular hologram of the plurality of holograms diffracts image light to the position of the user eye.