A security marking has a physically unclonable function (PUF) wherein the PUF includes a disordered multilayer photonic crystal structure having an electromagnetic transmission and/or reflection spectrum and/or spectra upon receipt of electromagnetic radiation within a photonic bandgap region of the structure that is unique to the structure.

A diffractive optical element (10) for a test interferometer (100) measures a shape of an optical surface (102). Diffractive shape measuring structures (16) are arranged on a used surface (14) of the element and generate a test wave (122) irradiating the surface when the element is arranged in the interferometer. At least one test field (18) several profile properties of test structures contained in the test field. The profile properties characterize a profile line of the test structures extending transversely with respect to the used surface and include a flank angle of the profile line, a profile depth and a depth of a microtrench in a bottom region of a trench-shaped profile of the test structures. The test field is arranged at one location of the used surface instead of the diffractive shape measuring structures such that the test field is surrounded by several diffractive shape measuring structures.

The present disclosure generally relates to methods of forming optical devices comprising nanostructures disposed on transparent substrates. A first process of forming the nanostructures comprises depositing a first layer of a first material on a glass substrate, forming one or more trenches in the first layer, and depositing a second layer of a second material in the one or more holes to trenches a first alternating layer of alternating first portions of the first material and second portions of the second material. The first process is repeated one or more times to form additional alternating layers over the first alternating layer. Each first portion of each alternating layer is disposed in contact with and offset a distance from an adjacent first portion in adjacent alternating layers. A second process comprises removing either the first or the second portions from each alternating layer to form the plurality of nanostructures.

An anti-reflective waveguide assembly comprising a waveguide substrate having a first index of refraction, a plurality of diffractive optical elements disposed upon a first surface of the waveguide and an anti-reflective coating disposed upon a second surface of the waveguide. The anti-reflective coating preferably increases absorption of light through a surface to which it is applied into the waveguide so that at least 97 percent of the light is transmitted. The anti-reflective coating is composed of four layers of material having different indices of refraction that the first index of refraction and an imaginary refractive index less than 1×10.sup.−3 but preferably less than 5×10.sup.−4.

A method for creating metadevices includes receiving, at a computing device, one or more boundary conditions for a metadevice. The method also includes processing, with an inverse-design algorithm stored in a memory of the computing device, the one or more boundary conditions to generate a metadevice structure design that satisfies the one or more boundary conditions. The method also includes converting, by a processor of the computing device, the metadevice structure design into a file that is compatible with an additive manufacturing device. The method further includes providing the file of the metadevice structure design to the additive manufacturing device.

Several unique configurations for interferometric recording of volumetric phase diffractive elements with relatively high angle diffraction for use in waveguides are disclosed. Separate layer EPE and OPE structures produced by various methods may be integrated in side-by-side or overlaid constructs, and multiple such EPE and OPE structures may be combined or multiplexed to exhibit EPE/OPE functionality in a single, spatially-coincident layer. Multiplexed structures reduce the total number of layers of materials within a stack of eyepiece optics, each of which may be responsible for displaying a given focal depth range of a volumetric image. Volumetric phase type diffractive elements are used to offer properties including spectral bandwidth selectivity that may enable registered multi-color diffracted fields, angular multiplexing capability to facilitate tiling and field-of-view expansion without crosstalk, and all-optical, relatively simple prototyping compared to other diffractive element forms, enabling rapid design iteration.

An optical assembly including a layer including a low refractive index material and a medium, and a functional layer formed on a surface of the layer. The layer includes the low refractive index material at a content of 60%-76% by mass.

A grating coupler may be fabricated by exposing a photopolymer layer to grating forming light for forming periodic refractive index variations in the photopolymer layer. The photopolymer layer may be exposed to apodization light for reducing an amplitude of the periodic refractive index variations in a spatially-selective manner. The apodization may also be achieved or facilitated by subjecting outer surface(s) of the photopolymer layer to a chemically reactive agent that causes the refractive index contrast to be reduced near the surface(s) of application. The apodized refractive index profile of the gratings facilitates the reduction of optical crosstalk between different gratings of the grating coupler.

A grating part includes a first transparent substrate having an optical grating on a first principal surface and a second transparent substrate having an optical grating on a first principal surface; a second principal surface of the first substrate on an opposite side from the first principal surface and a second principal surface of the second substrate on an opposite side from the first principal surface are bonded.

A method fabricates a transparent polymer plate or film. The method incudes applying an acrylate ink to a transparent substrate and illuminating the polymeric substrate and the acrylate ink with a light source to cause photopolymerization. The photopolymerization creates micro-louvre structures inside the transparent polymeric plate or film.