A colorimetric sensor for detecting an analyte of interest in a fluid sample includes a lamellar photonic material having alternating layers of a first polymer layer and a second polymer layer. Each first polymer layer can be a molecularly imprinted polymer defining a cavity shaped to receive an analyte of interest. The photonic material is configured such that, when an analyte contacts the photonic material and becomes disposed within a cavity of the molecularly imprinted polymer, a refractive property of the photonic material changes, causing a detectable color change in the sensor.

Integrated target waveguide devices and optical analytical systems comprising such devices are provided. The target devices include an optical coupler that is optically coupled to an integrated waveguide and that is configured to receive optical input from an optical source through free space, particularly through a low numerical aperture interface. The devices and systems are useful in the analysis of highly multiplexed optical reactions in large numbers at high densities, including biochemical reactions, such as nucleic acid sequencing reactions. The devices provide for the efficient and reliable coupling of optical excitation energy from an optical source to the optical reactions. Optical signals emitted from the reactions can thus be measured with high sensitivity and discrimination. The devices and systems are well suited for miniaturization and high throughput.

A fiber-optic sensing apparatus is provided, including an outer sleeve, an optical fiber sensor arranged within the outer sleeve, and a filling medium. The optical fiber sensor is capable of detecting a change of a refractive index or a change of surface plasmon waves over an outer surface of the outer sleeve. The filling medium may have a matching refractive index with the outer sleeve and with the optical fiber sensor. The outer sleeve may be exposed directly to the outside medium, or may be coated with at least one functional film layer such as a surface plasmon resonance (SPR)-active base film layer, or a reactive film layer that is reactive to a target molecule in the outside medium.

A digital assay for a micro RNA (miRNA) or other target analyte in a sample makes use of nanoparticles that absorb light at the resonant wavelength of a photonic crystal (PC). Such nanoparticles locally quench the resonant reflection of light from the PC when present on the surface of the PC. The nanoparticles are functionalized to specifically bind to the target analyte, and the PC surface is functionalized to specifically bind to the nanoparticles that have bound to the target analyte. The sample is exposed to the functionalized nanoparticles, and the individual nanoparticles bound to the PC surface can be identified and counted based on reduced intensity values in the reflected light from the PC. The number of bound nanoparticles that are counted in this way can be correlated to the abundance of the target analyte in the sample.

The invention relates to a diffractive device (18) for chemical and biological analysis based on structured receptors on waveguides, which comprises: a waveguide (1) and a recognition element (3) consisting of a grating with receptors (11) arranged on the waveguide (1) and are intended to interact with target compounds (12) present in a sample; and a radiation source (4) that emits an incident beam (5) propagated through the waveguide (1), interacting with the recognition element (3) and being diffracted according to Bragg's law, thereby generating a reflected beam (6) and a transmitted beam (7), which are collected by optical analysers (8, 17) that record parameters of the reflected beam (6) and of the transmitted beam (7), enabling multiple analyses to be conducted in a simple, fast, sensitive and quantitative manner, label-free and in real time.

A sensor architecture that uses fixed wavelength light and tunes a wavelength dependent response of a sensor may be used for detecting analytes in a wide range of applications. The sensor architecture is based on optical resonators or interferometers comprising optical waveguides. A resonance wavelength and/or transmission/reflection spectrum are affected by presence of an analyte adsorbed on a surface of the waveguide, and a setting of a phase modulator. The sensors include a sensor portion where part of the waveguide is exposed to a sample for sensing, and a phase modulator part. The phase modulator part may include a heater that is controlled to tune, or sweep, or modulate the resonant wavelength and/or spectrum of the sensor.

A three-dimensional porous photonic structure, whose internal pore surfaces can be provided with desired surface properties in a spatially selective manner with arbitrary patterns, and methods for making the same are described. When exposed to a fluid (e.g., via immersion or wicking), the fluid can selectively penetrate the regions of the structure with compatible surface properties. Broad applications, for example in security, encryption and document authentication, as well as in areas such as simple microfluidics and diagnostics, are anticipated.

An apparatus configured to detect a substance, and method of operating and forming the same. In one embodiment, the apparatus includes a tunable resonator including an upper Bragg reflector and a lower Bragg reflector separated by a porous matrix. The tunable resonator is configured to be illuminated by a light source and produce a first spectral optical response from a substance absorbed within the porous matrix. The apparatus also includes a detector positioned proximate the tunable resonator configured to provide a first absorption signal representing the first spectral optical response.

A method of directly measuring moisture content in an oil-filled transformer includes using an optical fiber that having a grating sensor, such as a Fiber Bragg grating, defined in the optical fiber. The various conductors (windings) in the transformer are insulated using an insulator such as paper and insulating oil is filled inside the transformer. Moisture in the transformer is absorbed by the paper that surrounds the windings. A moisture content at a specific location can be measured by placing the optical fiber with the grating sensor directly at the specific location to be measured. A physical parameter of the paper that absorbed moisture changes over time, causing a change in the grating sensor of the optical fiber which changes the spectral response of optical signals that are reflected by the grating sensor. The method provides an accurate method of measuring the moisture inside the transformer at the specific location.

A device for determining a refractive index may be provided. The device including at least one waveguide having a core and a cladding surrounding the core, the cladding being at least partly removed in at least one first longitudinal portion and the core including at least one fiber Bragg grating in at least one second longitudinal portion. A method for determining a refractive index or a pressure change in a fluid may also provided. The method may include at least one waveguide having a core and a cladding surrounding the core, the cladding being at least partly removed in at least one longitudinal portion. A method for producing such a device may also be provided.