A mode control system and method for controlling an output mode of a broadband radiation source including a photonic crystal fiber (PCF). The mode control system includes at least one detection unit configured to measure one or more parameters of radiation emitted from the broadband radiation source to generate measurement data, and a processing unit configured to evaluate mode purity of the radiation emitted from the broadband radiation source, from the measurement data. Based on the evaluation, the mode control system is configured to generate a control signal for optimization of one or more pump coupling conditions of the broadband radiation source. The one or more pump coupling conditions relate to the coupling of a pump laser beam with respect to a fiber core of the photonic crystal fiber.

Various metamaterials are disclosed. An example metamaterial comprises: a first portion with a plurality of nanoparticles; a second portion with a plurality of molecules configured to interlink with the plurality of nanoparticles; and a signal generator configured to provide a signal to the material. The first portion and the second portion of the material are configured to form a hybrid molecule-nanoparticle super-lattice. In some implementations, the first portion of the material is configured to have a mass configured to achieve, at least in part, a designated resonance frequency. The second portion of the material is, in some implementations, configured to have a molecular stiffness configured to achieve, at least in part, the designated resonance frequency. The signal generator is, in some implementations, configured to generate radio frequency (RF) signals.

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.

Techniques for enhancing the absorption of photons in semiconductors with the use of microstructures are described. The microstructures, such as pillars and/or holes, effectively increase the effective absorption length resulting in a greater absorption of the photons. Using microstructures for absorption enhancement for silicon photodiodes and silicon avalanche photodiodes can result in bandwidths in excess of 10 Gb/s at photons with wavelengths of 850 nm, and with quantum efficiencies of approximately 90% or more.

Embodiments of the present disclosure provide for methods of detecting, sensors (e.g., chromogenic sensor), kits, compositions, and the like that related to or use tunable macroporous polymer. In an aspect, tunable macroporous materials as described herein can be used to determine the presence of a certain type(s) and quantity of liquid in a liquid mixture.

A method of fabricating a visible spectrum optical component includes: providing a substrate; forming a resist layer over a surface of the substrate; patterning the resist layer to form a patterned resist layer defining openings exposing portions of the surface of the substrate; performing deposition to form a dielectric film over the patterned resist layer and over the exposed portions of the surface of the substrate, wherein a top surface of the dielectric film is above a top surface of the patterned resist layer; removing a top portion of the dielectric film to expose the top surface of the patterned resist layer and top surfaces of dielectric units within the openings of the patterned resist layer; and removing the patterned resist layer to retain the dielectric units over the substrate.

A gradient-index phononic crystal flat lens which controls the behavior of an acoustic wave having a designated frequency. The gradient-index phononic crystal flat lens may include one or more super cells each having a plurality of layers stacked in a vertical direction according to a target gradient index profile, wherein each of the layers is composed of an aggregate in which unit cells having scatterers formed with the same size in the centers thereof are arranged in a horizontal direction. The one or more super cells may each include a divider provided between the neighboring layers, and configured to force the acoustic wave to propagate in the horizontal direction within the gradient-index phononic crystal flat lens.

A 2D spatial differentiator operates in transmission and comprises a Si nanorod photonic crystal that can transform an image, Ein, into its second-order derivative, E.sub.out α ∇.sup.2 E.sub.in, allowing for direct discrimination of the edges in the image. The use of a 2D photonic crystal allows for differentiation and edge detection in all directions with a numerical aperture (NA) up to 0.315 and an experimental resolution smaller than 4 μm. The nanophotonic differentiator is able to be directly integrated into an optical microscope and onto a camera sensor, demonstrating the ease with which it can be vertically integrated into existing imaging systems. Furthermore, integration with a metalens is demonstrated for realizing a compact and monolithic image-processing system. In all cases, the use of the nanophotonic differentiator allows for a significant reduction in size compared to traditional systems, opening new doors for optical analog image processing in applications involving computer vision.

An optical telescope may include an array of optical lenslets in a common plane, and optical waveguides extending from respective optical lenslets and each having a common optical path delay. Further, at least one optical star coupler may be downstream from the optical waveguides, and an optical detector may be downstream from the at least one optical star coupler and having an optical image formed thereon.

The disclosed matter provides integrated metasurface devices for conversion between a waveguide mode and a free-space optical wave with a designer wavefront. In exemplary embodiments, the integrated metasurface devices include a thin waveguide, a waveguide taper, a leaky-wave metasurface defined within a high refractive index layer of dielectric material, and a low refractive index substrate. The device can manipulate all the four optical degrees of freedom of the free-space wavefront, namely: amplitude, phase, polarization orientation, and polarization ellipticity, by using a leaky-wave metasurface composed of meta-units with four structural degrees of freedom.