A compact bi-telecentric device includes refractive lenses and takes in light from a grid of emitters at the object plane and images them to a grid of receivers. It provides the capacity to combine multiple wavelengths of emitters at the object plane into a single receiver. The device is quite compact, less than 25 mm in length from object to image, and having a maximum diameter for any element of less than 4 mm. The device includes four optical lens elements, three of which have a positive focal length and one of which has a negative focal length. The device includes at least one diffractive optical element. The lens elements are separated into two distinct groups which each have positive optical power, separated by an aperture stop which may or may not be enabled by a physical surface. A diffractive element enables wavelength division multiplexing and compensates for distortion from the bi-telecentric device.

An apparatus for sorting orbital angular momentum eigenstates of one or more photons includes at least one transformation PBOE configured to sort orbital angular momentum eigenstates of the one or more photons, at least one phase correction PBOE configured to sort spin angular momentum eigenstates of the one or more photons. A method for sorting orbital angular momentum eigenstates of one or more photons includes using at least one transformation PBOE to sort orbital angular momentum eigenstates of the one or more photons, and using at least one phase correction PBOE to sort spin angular momentum eigenstates of the one or more photons.

There is provided a versatile optical element applicable both to an electrode layer required in a bank bill field and to an optical element required in an ID field. In an optical element (1) according to one embodiment of the present invention, a first layer (2) is arranged on a second layer (3) having a relief structure on a surface thereof, and a first region (4) and a second region (5) are provided. Electromagnetic waves incident at a preset specific angle from a side of the first layer (2) are totally reflected due to at least one of the relief structure in the first region (4) and a ratio of a refractive index of the second layer (3) with respect to a refractive index of the first layer (2), the electromagnetic waves incident at the specific angle from the side of the first layer (2) are not totally reflected but transmitted or refracted due to at least one of the relief structure in the second region (5) and the ratio of the refractive index of the second layer (3) with respect to the refractive index of the first layer (2), and only in case of observation performed from the specific angle on the first layer (2) side, the second region (5) has higher transparency than the first region (4), and a preset image is expressed by a transparency contrast therebetween.

An image display device includes a display panel displaying an image, and a diffractive element formed to operate in a 2D mode or a 3D mode so that the image of the display panel is perceived as a 2D image or a 3D image after passing through the diffractive element. In the image display device, the diffractive element includes a first substrate and a second substrate facing each other, a first electrode layer formed on the first substrate that includes a plurality of zones, a second electrode layer formed on the second substrate, and a liquid crystal layer interposed between the first substrate and the second substrate. Further, when the diffractive element operates in the 3D mode, a common voltage is applied to the second electrode layer, and polarity of voltages applied to the first electrode layer with respect to the common voltage is inverted every zone.

A light irradiation apparatus focuses light on a surface or an inside of an object to observe or process the object, and includes a laser light source, a lens, a lens, a mask, a wave plate, and a lens. The mask is a multi-ring mask for spatially intensity-modulating input light in a beam cross-section and outputting modulated light, and includes a plurality of ring-shaped light-shielding areas provided around a center position, and a transmitting area provided between two adjacent light-shielding areas out of the plurality of light-shielding areas. A radial width of each of the two adjacent light-shielding areas out of the plurality of light-shielding areas is larger than a radial width of the transmitting area provided between the two light-shielding areas.

Provided are meta illuminators. The meta illuminators according to embodiments include a first light emitter configured to emit pattern light, and a second light emitter configured to emit non-patterned light, wherein the first and second light emitters forms a single body. The first and second light emitters respectively include meta-surfaces that are different from each other, and the different meta-surfaces may be formed on a single material layer. The first light emitter includes a pattern region that transmits a portion of incident light, and the second light emitter does not include the pattern region. A mask may be arranged between the light source and the transparent substrate.

There are provided a lens having excellent mechanical strength, as well as an optical component employing the lens. The lens is a lens having a circular shape when viewed in a plan view, the lens having a thickness of not less than 1 mm and not more than 11 mm at a lens center, the lens having a lens diameter of not less than 2 mm and not more than 50 mm, the lens having a curvature of not less than −0.5 mm.sup.−1 and not more than 0.5 mm.sup.−1 at the lens center.

An optical element includes a conversion layer and a metal piece layer. The conversion layer is provided with a light-incidence surface including an uneven surface, the conversion layer being configured to receive light incident on the uneven surface and output the light from the uneven surface as light in a different state than the incident light. The metal piece layer is configured by a plurality of metal pieces to cover at least part of the uneven surface.

An optical element includes a substrate, an intermediate layer, a topmost layer, and a contiguous multitude of recessed and non-recessed areal regions. The intermediate layer is formed over a top surface of the substrate and has a refractive index n.sub.I. The topmost layer is formed directly on the intermediate layer and has a refractive index n.sub.T where n.sub.T≠n.sub.I. The intermediate and topmost layers are substantially transparent over an operational wavelength range that includes a design wavelength λ.sub.0. A subset of areal regions has a largest transverse dimension less than about λ.sub.0. Each non-recessed areal region includes corresponding portions of the intermediate and topmost layers. Each recessed areal region extends entirely through the topmost layer and at least partly through the intermediate layer. A fill medium fills the recessed areal regions. The areal regions are variously sized and distributed transversely across the optical element.

A lighting device for a vehicle, in particular a headlamp for a vehicle, having at least one light source, from which light emanates during the operation of the lighting device, a diffractive optical unit, including a plurality of gratings, which form a grating cell array, the light passing through the grating cell array during the operation of the lighting device in such a way that a light distribution is created in the outer area of the vehicle, at least one of the gratings of the grating cell array being designed as a volume hologram.