Abstract: A light guide element includes: a light guide plate; and a diffraction element that is disposed on a main surface of the light guide plate, in which the diffraction element includes a liquid crystal layer that is formed of a liquid crystal composition including a liquid crystal compound and has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one in-plane direction, a refractive index of the light guide plate is 1.70 or higher, and in a case where the refractive index of the light guide plate is represented by nd and a refractive index of the liquid crystal layer is represented by nk, nk?nd?0 is satisfied.

Abstract: An optical element includes a light guide plate, an incidence portion, and an emission portion, in which each of the incidence portion and the emission portion includes diffraction portions, the diffraction portion includes diffraction elements, the diffraction element includes a liquid crystal diffraction layer in which a direction of an optical axis of a liquid crystal compound changes while continuously rotating in one in-plane direction, and in a case where the direction in which the direction of the optical axis changes is set as an in-plane rotation direction and a length over which the optical axis rotates by 180° is set as an in-plane period, in-plane rotation directions of liquid crystal diffraction layers of incidence diffraction elements in at least two of a plurality of the incidence diffraction portions are different from each other.

Abstract: Provided is an optical communication device, such as a wavelength locker, a wavelength demultiplexer, an optical coupling system, and an optical switching system, using a small-sized lens element. An optical communication device includes, as a lens element, a liquid crystal diffractive lens element having an optically anisotropic layer that is formed using a composition containing a liquid crystal compound, and has a liquid crystal alignment pattern in which an orientation of an optical axis of the liquid crystal compound changes while continuously rotating toward one direction, in a radial shape from an inside toward an outside, and in the liquid crystal alignment pattern, in a case where a length over which the orientation of the optical axis rotates by 180° in one direction in which the optical axis changes is a single period, a length of the single period gradually decreases from the inside toward the outside.

Abstract: Provided are a small-sized optical coupling system and an optical communication device using the optical coupling system. An optical coupling system includes a liquid crystal optical element, and a photonic device having a plurality of photonic chips, and couples an optical fiber to the photonic device, in which each of the photonic chips includes a grating coupler, the liquid crystal optical element separates incident signal light depending on at least one of polarization or a wavelength to emit light in different directions, and each separated signal light component is incident into the grating coupler of the corresponding photonic chip.

Abstract: Provided are: an image display apparatus in which the utilization efficiency of a virtual image is high and the virtual image having high brightness uniformity can be displayed to be superimposed on a real image; and AR glasses including the image display apparatus. The image display apparatus includes: a display element; one or more cholesteric liquid crystal layers that reflect a display image of the display element; and a transparent reflection element that reflects the image reflected by the cholesteric liquid crystal layer to the cholesteric liquid crystal layer, in which at least one of the cholesteric liquid crystal layers has a structure having a region where a surface pitch changes in a thickness direction.

Abstract: Provided are: an image display apparatus that can display augmented reality in a virtual image is superimposed on a bright real scene; and AR glasses including the image display apparatus. The image display apparatus includes: a display element; and a reflective polarization diffraction element that reflects an image displayed by the display element, in which the polarization diffraction element has a region where a period of a diffraction structure decreases in a direction away from the display element.

Abstract: Provided are: a method of manufacturing an optical element that can display a clear image having no blurriness in AR glasses or the like; and an optical element that is manufactured using this manufacturing method.

Abstract: Provided are: a light guide element in which deterioration in image sharpness can be prevented and the entire area of a display image can be suitably observed irrespective of the visual line of a user, the position of eyes of the user, and the like; and an image display apparatus including the light guide element. The light guide element includes: a light guide plate that includes a first light guide layer and a second light guide layer; and an incidence diffraction element and an emission diffraction element that are laminated on the second light guide layer, in which in a case where a refractive index of the first light guide layer is represented by n1 and a refractive index of the second light guide layer is represented by n2 in the light guide plate, n1<n2 is satisfied.

Abstract: Provided are an optical element including a first optically-anisotropic layer consisting of a cured layer of a composition including a first liquid crystal compound, in which the first optically-anisotropic layer has 0.24 or more of a refractive index anisotropy ?n550 which is measured with light having a wavelength of 550 nm, the first optically-anisotropic layer has a first liquid crystal alignment pattern in which a direction of an optical axis derived from the first liquid crystal compound continuously changes rotationally in at least one in-plane direction, and in the first liquid crystal alignment pattern, in a case where a length ? over which the direction of the optical axis rotates 180° in a plane is defined as a single period, the length ? of the single period is 1.6 ?m or less; a method for forming a photo-alignment pattern; and a method for manufacturing an optical element.

Abstract: An object is to provide: an optical member with which an image display apparatus where multiple images are suppressed can be obtained; and an image display apparatus including the optical member.

Abstract: Provided are an optical member in which emission of stray light to the outside can be suppressed and an image display apparatus. The optical member includes: a light guide element including a light guide plate and an incidence diffraction element and an emission diffraction element that are disposed on a main surface of the light guide plate; and a polarization element that blocks transmission of light leaking to a side of the emission diffraction element opposite to an emission side, wherein the emission diffraction element is a polarization diffraction element, the polarization element is disposed on the side of the emission diffraction element opposite to the emission side, and the polarization element is disposed at a position overlapping the emission diffraction element in a plane direction of the main surface of the light guide plate.

Abstract: Provided are: a light guide element in which the occurrence of multiple images can be suppressed and a wide viewing angle can be obtained; and an image display apparatus including this light guide element.

Abstract: Provided are: a light guide element that includes an intermediate diffraction element to expand exit pupil such that a light utilization efficiency is high and a decrease in the brightness of an image to be displayed can be suppressed; and an image display apparatus.

Abstract: An object is to provide an optical element in which a wavelength dependence of reflection is small, a light guide element including the optical element, and an image display device including the light guide element. The optical element includes a plurality of cholesteric liquid crystal layers having different selective reflection center wavelengths, in which the cholesteric liquid crystal layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from a liquid crystal compound changes while continuously rotating in at least one in-plane direction, and in a case where a length over which the optical axis rotates by 180° in the in-plane direction is set as a single period, a permutation of lengths of selective reflection center wavelengths and a permutation of lengths of the single periods match each other in the cholesteric liquid crystal layers.

Abstract: Provided are a method of forming a photo-alignment film having a large size that can appropriately align a liquid crystal compound can be formed and a method of forming a liquid crystal layer having a large size in which alignment defects of a liquid crystal compound can be suppressed.

Abstract: Provided is a method of manufacturing an optical element in which aligning properties of an alignment pattern in a photo-alignment film is improved such that alignment defects of a liquid crystal compound in a liquid crystal layer can be suppressed. The method of manufacturing an optical element includes: an exposure step of performing interference exposure to a surface of a photo-alignment film including a photo-alignment material to form, on the photo-alignment film, an alignment pattern in which a direction of an optical axis derived from a liquid crystal compound changes while continuously rotating in at least one in-plane direction; and a liquid crystal layer forming step of applying a liquid crystal composition including a liquid crystal compound to the photo-alignment film where the alignment pattern is formed to form a liquid crystal layer, in which the photo-alignment material includes an azo compound, and the exposure step is performed in an environment having a relative humidity of 50% or less.

Abstract: Provided are a liquid crystal diffraction element which exhibits low scattering and high sharpness of diffracted light, and a method for producing the same.

Abstract: Provided are an optical laminate where the occurrence of crosstalk can be suppressed and the occurrence of multiple images can be suppressed, a light guide element, and an image display apparatus.

Abstract: Provided is a laser oscillation element including a cholesteric liquid crystal layer, in which even in a case where the intensity of excitation light is weak, laser oscillation can be induced. The laser oscillation element includes a cholesteric liquid crystal layer obtained by cholesteric alignment of a liquid crystal compound, in which in a cross-section of the cholesteric liquid crystal layer observed with a scanning electron microscope, bright portions and dark portions derived from the cholesteric liquid crystalline phase are tilted with respect to a main surface of the cholesteric liquid crystal layer, the cholesteric liquid crystal layer includes a colorant that emits light by excitation, and a luminescence wavelength range of the colorant and a selective reflection wavelength range of the cholesteric liquid crystal layer at least partially overlap each other.

Abstract: Provided is a method of manufacturing an optical element and an optical element, in which an alignment pattern can be formed with high manufacturing efficiency and high accuracy, an increase in manufacturing time caused by an increase in size can be suppressed, and a liquid crystal compound can be appropriately aligned. The method is a method of manufacturing an optical element, the optical element including a liquid crystal layer that is formed of a liquid crystal composition including a liquid crystal compound, an alignment film that aligns the liquid crystal compound of the liquid crystal layer, and a support, the method including: an alignment film forming step of forming the alignment film having a periodic unevenness shape on the support, the unevenness shape having a tilted surface that is tilted with respect to a surface of the support; and a liquid crystal layer forming step of forming the liquid crystal layer on the alignment film.