Methods and apparatuses related to fiducial designs for fiducial markers on glass substrates, or other transparent or translucent substrates, are disclosed. Example fiducial designs can facilitate visual recognition by enhancing edge detection in visual perception. In example fiducial designs, optical features on glass substrates can re-direct light so as to present a bright image region. Such optical features can include surface relief patterns formed in a coating on the surface of glass substrates. An exemplary method for manufacturing the fiducial markers can involve transfers of a fiducial design across a master mold or plate, a submaster mold or plate, and a target glass substrate. A fiducial marker can facilitate the use of the substrate in a variety of applications, including machine vision systems that facilitate automated performance of manufacturing processes on input working material.

An octave bandwidth, achromatic metalens configured to operate in light wavelengths having a range of approximately 640 nm to 1200 nm.

An eyepiece for use in front of an eye of a viewer includes a waveguide having a surface and a diffractive optical element (DOE) optically coupled to the waveguide. The DOE includes a plurality of first ridges protruding from the surface of the waveguide and arranged as a periodic array having a period, each respective first ridge has a first height and a respective first width. The DOE also includes a plurality of second ridges, each respective second ridge protruding from a respective first ridge and having a second height greater than the first height and a respective second width less than the respective first width. At least one of the respective first width, the respective second width, or a respective ratio between the respective first width and the respective second width varies as a function of a distance from a first edge of the DOE.

Provided are a diffraction grating structure (100), an imaging device (1000), and a wearable apparatus (2000). The diffraction grating structure (100) includes a waveguide sheet (10), a couple-in grating (20), a couple-out grating (30), and a functional layer (40). The couple-in grating (20) is configured to couple light in the waveguide sheet (10). Each of the waveguide sheet (10) and the couple-out grating (30) is configured to couple the light out to the functional layer (40). The functional layer (40) is configured to refract the light to an ambient environment and increase a light-outcoupling rate of the couple-out grating (30).

A metasurface optical device includes a substrate and a nano-structure layer disposed on the substrate. The nano-structure layer includes a plurality of nano-structure units. The plurality of nano-structure units extend in a direction away from the substrate, and central axes of the plurality of nano-structure units form corresponding angles with respect to a normal direction of the substrate, such that the plurality of nano-structure units are arranged obliquely relative to the substrate.

An optical combiner includes a first layer with a periodic arrangement of structures of a material with a first refractive index. A second layer overlies the structures on the first layer, and the second layer includes a material with a second refractive index. A difference between the first refractive index and the second refractive index, measured at 587.5 nm, is less than 1.5. The periodic arrangement of structures is configured such that the optical combiner produces, for an input signal incident on the first layer from air at an oblique elevation angle of greater than 20°, an output signal with three reflection peaks, each reflection peak having an average reflection of greater than 50% within a ±3° range of the elevation angle.

An optical device includes a liquid crystal layer having a first plurality of liquid crystal molecules arranged in a first pattern and a second plurality of liquid crystal molecules arranged in a second pattern. The first and the second pattern are separated from each other by a distance of about 20 nm and about 100 nm along a longitudinal or a transverse axis of the liquid crystal layer. The first and the second plurality of liquid crystal molecules are configured as first and second grating structures that can redirect light of visible or infrared wavelengths.

A laser beam combining device includes an emission optical system that emits a plurality of circular laser beams propagated coaxially and having mutually different wavelengths, and a diffractive optical element that is concentric and diffracts the plurality of circular laser beams. The diffractive optical element diffracts the plurality of circular laser beams in accordance with the wavelengths of the circular laser beams, such that local diffraction angles of diffracted light of the plurality of circular laser beams incident at mutually different local incidence angles are equal to each other.

Display devices include waveguides with in-coupling optical elements that mitigate re-bounce of in-coupled light to improve overall in-coupling efficiency and/or uniformity. A waveguide receives light from a light source and/or projection optics and includes an in-coupling optical element that in-couples the received light to propagate by total internal reflection in a propagation direction within the waveguide. Once in-coupled into the waveguide the light may undergo re-bounce, in which the light reflects off a waveguide surface and, after the reflection, strikes the in-coupling optical element. Upon striking the in-coupling optical element, the light may be partially absorbed and/or out-coupled by the optical element, thereby effectively reducing the amount of in-coupled light propagating through the waveguide. The in-coupling optical element can be truncated or have reduced diffraction efficiency along the propagation direction to reduce the occurrence of light loss due to re-bounce of in-coupled light, resulting in less in-coupled light being prematurely out-coupled and/or absorbed during subsequent interactions with the in-coupling optical element.

An optical element includes an optical block constructed of a first material having a % transmission of at least 50% throughout a spectral range of 300 nm to 2700 nm through at least a thickness of the optical block. The optical block comprises a surface. A grating layer constructed of a second material is disposed on the surface of the optical block, the grating layer comprising a first surface that is directly in contact with the surface of the optical block and a second surface comprising a plurality of diffraction features forming a diffraction grating.