31 results about "Refractive index contrast" patented technology

The invention discloses a radiation refrigeration coating with high refractive index contrast, and belongs to the technical field of radiation refrigeration coatings. The radiation refrigeration coating with high refractive index contrast comprises the following raw materials: hollow microspheres, a high refractive index pigment, a film-forming substance, a solvent and an auxiliary agent. The coating process of the radiation refrigeration coating film comprises two coating steps: firstly, coating an inner layer coating film on the surface of a base material by using the radiation refrigeration coating with rutile type titanium dioxide as a high-refractive-index pigment as a raw material; and coating the surface of the inner-layer coating film with an outer-layer coating film by using the radiation refrigeration coating with high-refractive-index pigment being zirconium dioxide and / or zirconium silicate as a raw material. According to the invention, a closed and independent bubble structure is introduced into the coating by adopting the hollow microspheres, and the preferable high-refractive-index pigment is matched, so that the refractive index difference value between adjacent components in a coating film is increased, and the sunlight reflectivity of the coating film is remarkably enhanced, thereby realizing excellent radiation refrigeration performance under strong sunlight irradiation.

An optical metasurface film includes a flexible polymeric film having a first major surface, a patterned polymer layer having a first surface proximate to the first major surface of the flexible polymeric film and having a second nanostructured surface opposite the first surface, and a refractive index contrast layer adjacent to the nanostructured surface of the patterned polymer layer forming a nanostructured bilayer with a nanostructured interface. The nanostructured bilayer acts locally on amplitude, phase, or polarization of light, or a combination thereof and imparts a light phase shift that varies as a function of position of the nano structured bilayer on the flexible polymeric film. The light phase shift of the nanostructured bilayer defines a predetermined operative phase profile of the optical metasurface film.

A device includes first, second and third elements fabricated on a common substrate. The first element includes an optical source, the second element includes at least one optical facet coupled to free space, and the third element includes a waveguide that optically couples the first element to the second element. The optical facet, having a compound III-V semiconductor material as a core and a dielectric material as a cladding, is characterized by a refractive index contrast between the core and the cladding that is greater or equal to 1. An optical beam exiting the facet is characterized by a central beam propagation axis and a FWHM beam divergence greater than 40 degrees referred to at least one axis perpendicular to the central beam propagation axis.

The invention presents a light coupling system and design method for highly efficient coupling of Nanowires or Nanowires with embedded Quantum Dots (NWQDs) to optical waveguides. A mesoscale optical dielectric microelement, like a dielectric microsphere (or alternatively half-sphere, cylinder, half-cylinder of mesoscale dimensions) is placed between the nanowire and the optical waveguide, with optimized: 1) Size (diameter) and 2) Refractive index of microsphere, 3) Distance between the nanowire and the microsphere, 4) Distance between microsphere and waveguide. The photonic nanojet emitted by the microsphere excites efficiently the guided eigenmode(s) of the input waveguide. Application of the method has been demonstrated in the case of directly laser written waveguides of low refractive index contrast in silica and silica-on-silicon platforms. The invention is expected to have a high impact in Quantum technology such as optical quantum computers.

The invention discloses a tunable band elimination filter based on a quantum well structure photon time crystal and a method. The tunable band elimination filter comprises the quantum well structure photon time crystal; the quantum well structure photon time crystal comprises a first photon time crystal section, a time domain quantum well section and a second photon time crystal section which are connected in sequence; when an electromagnetic signal is propagated, the electromagnetic signal sequentially passes through the first photon time crystal section, the time domain quantum well section and the second photon time crystal section, so that a stable band gap region and a controllable resonance response are formed in a momentum space; a fitting relation between a local state equivalent wave vector and a time structure parameter is established by adjusting a time section proportion parameter and a refractive index contrast ratio in a quantum well structure photon time crystal, so that the local state quantity and momentum position of an electromagnetic signal are regulated and controlled; and frequency spectrum regulation of the electromagnetic signal is realized through a corresponding relation between the momentum space and the frequency domain space. The frequency spectrum regulation and control precision and the system stability are improved.

Embodiments described herein relate to encapsulated optical devices and methods of forming optical devices with controllable air-gapped encapsulation. In one embodiment, a plurality of openings are formed in a support layer surrounding the plurality of optical device structures to create a high refractive index contrast between the optical device structures, the support layer, and the openings. In another embodiment, sacrificial material is disposed in-between the optical device structures and then an encapsulation layer is disposed on the optical device structures. The sacrificial material is removed, forming a space bounded by the encapsulation layer, the substrate, and each of the optical device structures. In yet another embodiment, the encapsulation layer is disposed over the optical device structures forming a space bounded by the encapsulation layer, the substrate, and each of the optical device structures.

A self-mixing interferometry SMI laser sensor (1) comprises a vertical cavity surface emitting laser (10) (VCSEL) configured to emit laser radiation, the VCSEL comprising a first distributed Bragg reflector (11) (DBR), a second DBR (12), and a cavity region (13) comprising an active light generating region (13a), where the cavity region (13) is arranged in a layer structure between a front side of the first DBR (11) and a back side of the second DBR (12). Wherein at least one of the first and second DBRs (11, 12) comprises a first contrast region (14) and a second contrast region (15), the first contrast region (14) having a first refractive index contrast [Delta] n1 with respect to an emission wavelength of the VCSEL (10), and the second contrast region (15) having a second refractive index contrast [Delta] n2 / n greater than the first refractive index contrast [Delta] n1 / n.

The present invention provides a novel optical waveguide configuration in which the impact of a fabrication error on optical circuit characteristics is suppressed, while reducing the size of of a waveguide with a high refractive index contrast and maintaining characteristics such as a stable refractive index. An optical circuit according to the present disclosure comprises an optical waveguide that achieves characteristic optical confinement. The optical waveguide includes: a slab-shaped first core; and a second core having a rectangular cross-section. By suppressing the amount of change in the refractive index in directions parallel and perpendicular to the substrate surface, the impact of a manufacturing error on the optical circuit characteristics is mitigated. It is also possible to suppress propagation loss since most of the optical power is confined in the slab-shaped first core, which does not require patterning.

A multiport passive photonic light circuit chip has multiple waveguides written in at least two layers on a glass substrate. Some waveguides connect transmitting and receiving ports of an optical channel, some waveguides redirect a fraction of optical signals to some other receiving ports, and waveguides have circular cross-sectional shapes wherein a refractive index contrast is in the range of 0.2% to 2%.

An optical metasurface film, comprising: a flexible polymer film having a first major surface; a patterned polymer layer having a first surface adjacent to the first major surface of the flexible polymer film and having a second nanostructured surface opposite to the first surface; and a refractive index contrast layer adjacent to the nanostructured surface of the patterned polymer layer, thereby forming a nanostructured bilayer with a nanostructured interface. The nanostructured bilayer locally acts on the amplitude, phase or polarization of light or a combination thereof, and applies an optical phase shift that varies with the position of the nanostructured bilayer on the flexible polymer film. The optical phase shift of the nanostructured bilayer defines a predetermined operating phase distribution of the optical metasurface film.

The present disclosure provides a photonic system, comprising: a PIC comprising a first SiN waveguide; and a second SiN waveguide vertically tapered by increasing thickness in a direction towards the first SiN waveguide and vertically tapered by decreasing thickness in a direction away from the first SiN waveguide, wherein: the first SiN waveguide comprises a tapered end having a first effective index n1; and the second SiN waveguide and a third SiN waveguide together form first and second low-index contrast sections of an effective index n2 at the ends, a third high-index contrast section between the first and second low-index contrast sections, the third high-index contrast section having a third effective index n3 and a vertical taper that adiabatically couples the first and second low-index contrast sections to the third high-index contrast section, n3 is close to n1 and n3 > n2, and the tapered end of the first SiN waveguide is optically coupled to the third high-index contrast section.

An optical metasurface film includes a flexible polymeric film having a first major surface, a patterned polymer layer having a first surface proximate to the first major surface of the flexible polymeric film and having a second nanostructured surface opposite the first surface, and a refractive index contrast layer including a refractive index contrast material adjacent to the nanostructured surface of the patterned polymer layer forming a nanostructured bilayer with a nano structured interface. The nanostructured bilayer comprising a plurality of nanostructures disposed on the flexible polymeric film. The nanostructured bilayer imparts a light phase shift that varies as a function of position of the nano structured bilayer on the flexible polymeric film. The light phase shift of the nanostructured bilayer defines a predetermined operative phase profile of the optical metasurface film. A light reflecting layer is in optical communication with the nano structured bilayer.

To provide optical metasurface polymeric films.SOLUTION: An optical metasurface film includes: a flexible polymeric film having a first major surface; a patterned polymer layer having a first surface proximate to the first major surface of the flexible polymeric film and having a second nanostructured surface opposite the first surface; and a refractive index contrast layer containing a refractive index contrast material adjacent to the nanostructured surface of the patterned polymer layer forming a nanostructured bilayer with a nanostructured interface. The nanostructured bilayer acts locally on the amplitude, phase, polarization of light or on a combination thereof, and imparts a light phase shift that varies as a function of the position of the nanostructured bilayer on the flexible polymeric film. The light phase shift of the nanostructured bilayer defines a predetermined operative phase profile of the optical metasurface film.SELECTED DRAWING: Figure 1

The invention provides a double-layer silicon nitride grating coupler for a visible light wave band. The double-layer silicon nitride grating coupler comprises a substrate, a lower cladding, a first layer of silicon nitride, an interlayer, a second layer of silicon nitride and an upper cladding from bottom to top, the first layer of silicon nitride comprises a first layer of silicon nitride grating and a silicon nitride waveguide, and the second layer of silicon nitride is a second layer of silicon nitride grating and is output by the lower layer of silicon nitride waveguide, so that relatively high coupling efficiency is realized. Due to the visible light wave band, the thickness of the first layer of silicon nitride and the second layer of silicon nitride does not exceed 500nm. According to the double-layer silicon nitride grating coupler, the vertical symmetry of gratings is broken through, high-directivity propagation of light waves is achieved through proper position arrangement of the two layers of silicon nitride gratings, and meanwhile the refractive index contrast ratio and the coupling efficiency can be improved through the double-layer gratings; on the premise that the grating period is not affected, the technology of the double-layer silicon nitride grating coupler manufactured based on the two uniform fully-etched gratings is simple.

The invention presents and demonstrates a novel light coupling system and design method for highly efficient coupling of Nanowires or Nanowires with embedded Quantum Dots (NWQDs) to optical waveguides, and is based on an optical arrangement employing an mesoscale optical dielectric microelement, like a dielectric microsphere (or alternatively half-sphere, cylinder, half-cylinder of mesoscale dimensions) placed between the nanowire and the optical waveguide, suitably optimized in terms of: 1) Size (diameter) of the microsphere, 2) Refractive index of microsphere, 3) Distance between the nanowire and the microsphere, 4) Distance between microsphere and waveguide. Upon suitable design of the optical arrangement, the photonic nanojet emitted by the microsphere illuminated by the nanowire, excites efficiently the guided eigenmode(s) of the input waveguide, thus launching optimally light with high coupling efficiency to lossless guided modes. The method is tolerant and robust in terms of displacements, misalignments, and imperfections given also the current state of the art tools, like nano / micro manipulators for accurate handling of such elements (nanowires, microspheres). Application of the method has been successfully demonstrated in the most demanding case of directly laser written waveguides of low refractive index contrast in silica and silica-on-silicon platform. The invention solves a very challenging problem and the solution is expected to have a high impact in Quantum technology due to the interest of developing optical quantum computers based on highly customised and scalable quantum photonic integrated circuits.

The present invention discloses a real-time tunable dispersion wave generation system and method based on a thin-film lithium niobate waveguide. The present invention utilizes the mode hybridization characteristics in a high refractive index contrast waveguide to cause a sudden change in the dispersion characteristics at a specific wavelength, and in the supercontinuum spectrum finally generated, a high-power, narrow-bandwidth, spectrally isolated mode hybridization dispersion wave can be obtained at this wavelength. At the same time, combined with the thermo-optical birefringence effect of the lithium niobate crystal, the real-time tuning of the mode hybridization dispersion wave is achieved by thermoelectrically regulating the temperature of the waveguide. The present invention is implemented by an ultrashort pulse laser, an adjustable DC regulated power supply, a polarization controller, a lens fiber, a thin-film lithium niobate chip, a metal heating electrode, an optical spectrum analyzer, and optical fibers and wires connecting them. The present invention utilizes an ultrashort pulse laser to efficiently and directionally transfer energy to a target wavelength range on a single thin-film lithium niobate waveguide, generating a high-power, spectrally isolated, real-time tunable mode hybridization dispersion wave.

Tunable VCSELs (TVCSELs) employing expanded material systems with expanded mechanical / optical design space for semiconductor DBR mirrors on GaAs substrates. One is the InGaAs / AlGaAsP material system. It adds indium In to decrease InGaAs H-layer bandgap for higher refractive index and higher DBR layer refractive index contrast. Adding phosphorus P gives independent control of bandgap and strain of AlGaAsP low refractive index L-layers. The tensile strain of AlGaAsP L-layer compensates compressive strain of InGaAs H-layer and lowers the cumulative strain of the multilayer DBR structure. Another option is the InGaAsN(Sb) / AlGaAsP material system, where both types of layers can be lattice matched to GaAs. It uses indium In and nitrogen N, and possibly antimony Sb, to get independent control of strain and bandgap, and thus refractive index, of dilute nitride InGaAsN(Sb) H-layers, with lower bandgap and higher refractive index than starting GaAs. Using expanded material system enables reliable DBR mirrors with higher reflectivity and spectral bandwidth and tunable VCSELs with wider tuning range.

This invention discloses a high-refractive-index contrast radiation-cooling coating, belonging to the technical field of radiation-cooling coatings. The raw materials of this invention's high-refractive-index contrast radiation-cooling coating include hollow microspheres, high-refractive-index pigments, film-forming substances, solvents, and additives. The coating process of this invention's radiation-cooling coating is a two-coat process. First, an inner coating is applied to the substrate surface using the radiation-cooling coating with rutile titanium dioxide as the high-refractive-index pigment. Then, an outer coating is applied to the surface of the inner coating using the radiation-cooling coating with zirconium dioxide and / or zirconium silicate as the high-refractive-index pigments. This invention introduces a closed, independent bubble structure into the coating using hollow microspheres, combined with a preferred high-refractive-index pigment, to increase the refractive index difference between adjacent components in the coating, significantly enhancing its solar reflectance, thereby achieving excellent radiation-cooling performance under strong sunlight.

A photonic device including a first waveguide and a second waveguide is provided. The device includes an interconnect coupled with the first waveguide and the second waveguide. The interconnect includes a substrate. The interconnect includes a film including a refractive index contrast (RIC) polymer and a core. The core includes a first domain having a first refractive index. The core includes a second domain adjacent to the first domain and having a second refractive index. The second refractive index is less than the first refractive index. The core includes a third domain adjacent to the second domain and having a third refractive index. The third refractive index is less than the second refractive index. The second domain is disposed between the first domain and the third domain. The refractive index of the substrate is less than the first refractive index, the second refractive index, and the third refractive index.

The invention discloses a femtosecond laser manufacturing method of a total positive refractive index or total negative refractive index change optical waveguide in a single crystal, and relates to the technical field of integrated photons. The method specifically comprises the following steps: adjusting the transverse intensity distribution of a femtosecond laser beam through a slit shaping and oil-immersed objective lens technology to obtain a shaped femtosecond laser beam, and then focusing the femtosecond laser beam into a transparent single crystal material; a positive refractive index change area is constructed to form a waveguide core layer in similar photonic crystal arrangement or a negative refractive index change area is constructed to form a waveguide cladding in similar photonic crystal arrangement through a mode of multiple femtosecond laser direct writing, and then a Type-I type core layer waveguide or a Type-II type cladding waveguide is formed. By adopting the method disclosed by the invention, the waveguide with high refractive index contrast ratio, high precision and low loss is formed in the transparent single crystal material, and the section of the waveguide can be customized into any shape. The method is suitable for various active / passive transparent single crystal materials, and has a wide application prospect in the fields of integrated optical amplifiers and light quantum chips.

A self-mixing interferometric, SMI, laser sensor comprises a vertical cavity surface emitting laser, VCSEL, configured to emit laser radiation, the VCSEL comprising a first distributed Bragg reflector, DBR, a second DBR and a cavity region including an active light generation region, wherein the cavity region is arranged in a layer structure between a front side of the first DBR and a back side of the second DBR. Therein at least one of the first and second DBR comprises a first contrast region and a second contrast region, the first contrast region having a first refractive index contrast Δn1 regarding an emission wavelength of the VCSEL and the second contrast region having a second refractive index contrast Δn2 / n larger than the first refractive index contrast Δn1 / n.

The invention relates to a nonvolatile reconfigurable mode converter and a preparation method thereof. The mode converter comprises a first waveguide and a second waveguide, a plurality of phase change materials are deposited on the first waveguide and the second waveguide respectively, and the states of the phase change materials are controlled respectively to achieve conversion from a fundamental mode to different high-order modes. According to the invention, the conversion among a plurality of different modes can be realized only by using a single device, the utilization rate of the device is improved, the design and manufacturing cost of the device is obviously reduced, and the expandability is realized; the phase-change material has non-volatility, so that the power consumption of the device can be remarkably reduced; reconfigurability of the device is achieved through reversible phase change of the phase change material, and due to the fact that the refractive index contrast ratio between the crystalline state and the amorphous state of the phase change material is large, the size of the device can be remarkably reduced, and the integration level of a photon chip is improved.

The present invention is directed to refractive index contrast (“RIC”) polymers and methods for producing and using the same. In one particular embodiment, RIC polymers of the invention can be used as waveguides. RIC polymers of the invention are produced from a monomeric mixture comprising a first monomer and a second monomer comprising an acid-labile protecting group, where a first polymer produced from the first monomer has a different refractive index compared to the refractive index of a second polymer produced from the second monomer. The base refractive index of RIC polymers can be tuned by controlling the amount of the first and the second monomers. Furthermore, the refractive index of the waveguide can be modulated by the amount of acid-labile protecting group removal.

An organic photovoltaic device comprises a first electrode, at least one organic heterojunction layer positioned over the first electrode, a second electrode positioned over the organic heterojunction layer, and a thin film stack positioned over the second electrode, comprising a plurality of sublayers of a first dielectric material alternating with a plurality of sublayers of a second dielectric material, wherein at least one of the plurality of sublayers of the first dielectric material has a thickness that is different from another of the plurality of sublayers of the first dielectric material, wherein the organic photovoltaic device has a mean transmittance of between 10% and 100% for light between 420 nm and 670 nm, with a variance of ±10%, and wherein an index contrast between the sublayers in the thin film stack is at least 0.1. A method of fabricating an organic photovoltaic device is also disclosed.

A double-inverse opal photonic crystal resin film is formed by embedding nanospheres in pores of polyacrylate inverse opal framework material and then filling the pores of the double-inverse opal photonic crystal resin film with an ethanol solution with hydrophilic acrylamide dissolved therein followed by photopolymerization to form a polyacrylamide network, so as to obtain the double-inverse opal photonic crystal resin film using water as ink. A mass fraction of hydrophilic acrylamide in the ethanol solution is 2 to 8 wt. %. The resin film can induce water to penetrate into the pores of the double-inverse opal photonic crystal resin film, making the nanospheres in the pores of the inverse opal framework distribute from random to order under the action of buoyancy force, thereby eliminating scattering interference and producing brilliant structural colors by regulating refractive index contrast.

An integrated sensor includes a substrate made of a first semiconductor material having a first optical refractive index. The substrate includes a pixel array, wherein each pixel has a photosensitive active zone formed by an index contrast zone including a matrix of the first semiconductor material and a periodic structure embedded in the matrix. The periodic structure extends from the backside of the substrate and has a two-dimensional periodicity in a parallel plane with the backside. A value of the periodicity is linked with the wavelength of the optical signal and with the first refractive index. Elements of the periodic structure are formed of a second optically transparent material having a second refractive index less than the first refractive index. These elements are positioned at locations defined by the periodicity except for at one location defining a region, preferably central, that is devoid of a corresponding one of the elements.

To provide an optical waveguide device in the field of mid-infrared photonics and a method for manufacturing such a device.SOLUTION: The device comprises a fluoride glass substrate having a local concentration of a chemical element at an internal contact and a waveguide inscribed along a path defined in the substrate. The waveguide is formed by directing a focused ultra-short laser pulse into the substrate and scanning the pulse to induce migration and densification of chemical elements at the inner contacts, resulting in a positive refractive index contrast. Fluoride glass substrates can include zirconium fluoride and modifiers such as barium fluoride, aluminum fluoride, and rare earth elements to enable optical gain. The described technology further encompasses an integrated photonics device including a waveguide laser with mirrors and gratings defining a laser cavity for use in sensing, communications, and laser systems.SELECTED DRAWING: Figure 1

The invention belongs to the technical field of functional thin film materials, and particularly relates to an entropy stabilizing material with a high optical quality factor and a preparation method of the entropy stabilizing material. In order to solve the problem that in the prior art, a high-symmetry crystal system is difficult to form due to strong orbital hybridization of a material in a middle-infrared band, so that low refractive index contrast ratio and low extinction coefficient of a phase change material are difficult to consider at the same time, the invention provides a light element and heavy element synergistic high-entropy doping strategy, and light elements Si and Ge and a heavy element Te are jointly introduced into a Sb2Se3 system, so that the phase change material has high refractive index contrast ratio and low extinction coefficient. And the high-entropy phase change material Si < x > Ge < y > Sb < 1-x-y > Se < 1-y > Tez is successfully prepared. The material is converted into a high-symmetry cubic structure from a low-symmetry orthogonal structure under high configuration entropy driving, p-track alignment is achieved, the optical quality factor of the material is greatly improved compared with that of traditional Ge2Sb2Te5, the material bottleneck of near-infrared and middle-infrared band all-optical memory computing image processors is broken through, and the application prospect is wide. And a key material basis is provided for practical application of the system in an intelligent visual system.

A grating coupler can be fabricated by exposing a photopolymer layer to grating-forming light to form a periodic refractive index variation in the photopolymer layer. The photopolymer layer can be exposed to apodized light to reduce the amplitude of the periodic refractive index variation in a spatially selective manner. Apodization can also be achieved or facilitated by subjecting the outer surface(s) of the photopolymer layer to a chemical reagent that reduces the refractive index contrast near the applied surface(s). The apodized refractive index profile of the grating helps reduce optical crosstalk between different gratings of the grating coupler.

The invention belongs to the technical field of optical imaging and computational optics, and particularly relates to a three-dimensional spectrum allocation interpolation and weighted stacking method for optical diffraction tomography reconstruction, which comprises the following steps of: firstly, converting complex amplitude distribution obtained at each inclined illumination angle into a three-dimensional frequency domain point set; and for a frequency spectrum point of a non-integer coordinate on the kz axis, calculating the proportion according to the distance between the frequency spectrum point and an adjacent integer point, and distributing a complex phase value of the point to integer frequency points on two sides so as to obtain more non-negative frequency spectrum information. Secondly, different weights are given to the frequency domain data of each view angle by using the difference of frequency spectrum intensity under different incident angles, and the inclined illumination contribution is highlighted, so that the refractive index contrast and the edge extraction capability after reconstruction are improved. According to the method, the coverage rate and precision of scattering potential three-dimensional frequency spectrum filling are remarkably enhanced, discrete Fourier space interpolation errors are reduced, and the problems of low refractive index and axial artifacts caused by limited angle illumination are effectively relieved.