A coating including an ordered spatial distribution of a plurality of nanoparticles; and a polymer medium is disclosed. Also disclosed is an article, such as an optical device, can include the coating, on a substrate. A multilayer structure can include the coating with a high refractive index layer adjacent to the coating. A method of making the coating, the article, and the multilayer structures is disclosed.

Provided is a polyester film for a touchscreen module substrate of a foldable display which is free of occurrence of a crack at a folding portion thereof, in order to provide a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The polyester film for a touchscreen module substrate of a foldable display satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

The present disclosure relates to a method for imaging an optical signal received by a graded index (GRIN) optical element to account for known variations in a graded index distribution of the GRIN optical element. The method may involve using a plurality of optical detector elements to receive optical rays received by the GRIN optical element at a plane, where the plane forms a part of the GRIN optical element or is downstream of the GRIN optical element relative to a direction of propagation of the optical rays. The optical rays are then traced to a plurality of additional specific locations on the plane based on the known variations in the graded index distribution of the GRIN optical element. A processor may be used to determine information on both an intensity and an angle of the received optical rays at each one of the plurality of specific locations on the plane of the GRIN optical element.

Gradient refractive index (GRIN) materials can include multi-phase composites having substances with differing refractive indices disposed non-uniformly within one another. Particular glass composites having a gradient index of refraction can include: an amorphous phase, and a phase-separated region disposed non-uniformly within the amorphous phase. The glass composites include a mixture containing: GeZ.sub.2 and A.sub.2Z.sub.3 in a combined molar ratio of about 60% to about 95%, and CsX and PbZ in a combined molar ratio of about 5% to about 40%, where A is As, Sb or Ga, X is Cl, Br or I, and Z is S or Se. When A is As, the glass composites include PbZ in a molar ratio of about 15% or less. The amorphous phase and the phase-separated region have refractive indices that differ from one another. More particularly, A is Ga or As, X is Cl, and Z is Se.

An organic light emitting diode (OLED) display panel with a light field camera includes a glass covering plate, an OLED pixel layer, and image sensor. A gradient refractive index lens is formed on the glass covering plate. A refractive index of the gradient refractive index lens gradually varies from a center of the gradient refractive index lens to an outer periphery. The OLED pixel layer is disposed on a bottom surface of the glass covering plate and includes OLED pixel units. A micro lens array is embedded on the OLED pixel layer and includes gradient refractive index micro lenses. A refractive index of each gradient refractive index micro lens gradually varies from a center of the gradient refractive index micro lens to an outer periphery. The image sensor is disposed on a bottom surface of the OLED pixel layer. The light field camera can acquire clear images without focusing.

An embodiment apparatus comprises an optically transparent substrate having first and second surfaces; a piezoelectric membrane, arranged at the first surface, that oscillates in response to a light beam propagated through the substrate; at least one reflective facet facing the substrate and arranged at the piezoelectric membrane; and an optical element receiving the light beam at an input end and guiding the light beam towards an output end coupled to the second surface. The optical element incorporates a light focusing path focusing the light beam at a focal point at the piezoelectric membrane, and at least one light collimating path collimating the light beam onto the at least one reflective facet. The optical element guides light reflected from the at least one reflective facet to the input end, the reflected light indicating a position of the optical element with respect to the focal point.

Sub-diffraction limited fluorescent images using a fiber-based stimulated emission depletion (STED) microscope are reported. Both excitation and depletion beams are transported through polarization-maintaining fiber and a lateral resolution of 100 nm has been achieved.

Optical beam steering and focusing systems, devices, and methods that utilize diffractive waveplates are improved to produce high efficiency at large beam deflection angles, particularly around normal incidence, by diffractive waveplate architectures comprising a special combination of liquid crystal polymer diffractive waveplate both layers with internal twisted structure and at a layer with uniform structure.

The present disclosure provides improved optical systems for particle processing (e.g., cytometry including microfluidic based sorters, drop sorters, and/or cell purification) systems and methods. More particularly, the present disclosure provides advantageous micro-lens array optical detection assemblies for particle (e.g., cells, microscopic particles, etc.) processing systems and methods (e.g., for analyzing, sorting, processing, purifying, measuring, isolating, detecting, monitoring and/or enriching particles.

An optical fiber device may include an optical waveguide to guide a laser output from a first end of the optical waveguide to a second end of the optical waveguide. The optical fiber device may include a fiber telescope optically coupled to the second end of the optical waveguide to modify the laser output. The fiber telescope may include a first graded-index optical element, a first facet of the first graded-index optical element being fused to the second end of the optical waveguide; and a second graded-index optical element, a first facet of the second graded-index optical element being fused to a second facet of the first graded-index optical element.