A tunable colorimetric sensor/optical filter is based on a lithography-free, asymmetric Fabry-Perot cavity. The sensor has a thin-film structure formed by a lossy, porous nanoplasmonic top film deposited on an actively tunable spacer middle layer, and a reflective base layer (either a metal or semiconductor). The structure is fabricated using wafer-scale PVD processes, and the middle layer responds to the presence of a stimulus in the local environment, by expanding in thickness resulting in a shift in resonance wavelength and thus an obvious change in color of the sensor, which color change is detectable by the naked-eye. Such layered geometries exhibit vibrant, macroscopic structural coloration owing to the broadband optical absorption of the top film, enabling the change in spacer thickness to be transduced visually, circumventing the need for sophisticated optical equipment for signal readout to observe the presence of the environmental stimulus.

A miniature optical biosensor and biosensor array where high sensitivity for detection of biomolecular interaction does not require a fluorescent label. Non-linear frequency-shifts of optical resonators (‘nanobeams’) provide a digital all-or-nothing response to equilibrium binding of a biomarker to surface-immobilized bio-recognition elements, a signal suitable to identify active components in genetic and proteomic circuits, as well as toxic substances. The threshold level for the digital response is adjustable to accommodate for varying receptor affinities. A bistable cavity sensing (BCS) method can be used to track the shift of the resonance induced by the analyte more precisely than the conventional cavity sensing method, where the resolution is limited by the cavity linewidth. BCS method can be used to quantitate the concentration of the analyte, and their binding kinetics, affinities and etc.

The invention relates to a surface refractive index scanning system for characterization of a sample. The system comprises a grating device for holding or receiving the sample, the device comprising at least a first grating region having a first grating width along a transverse direction, and a second grating region having a second grating width in the transverse direction. The first grating region and the second grating region are adjacent in the transverse direction, wherein the first grating region has a grating period Λ.sub.1 in a longitudinal direction, and the second grating region has a grating period Λ.sub.2 in the longitudinal direction, where the longitudinal direction is orthogonal to the transverse direction. A grating period spacing ΔΛ=Λ.sub.1-Λ.sub.2 is finite. Further, the first and second grating periods are chosen to provide optical resonances for light respectively in a first wavelength band and a second wavelength band, light is being emitted, transmitted, or reflected in an out-of-plane direction, wherein the first wavelength band and the second wavelength band are at least partially non-overlapping in wavelength. The system further comprises a light source for illuminating at least a part of the grating device with light at an illumination wavelength band. Additionally, the system comprises an imaging system for imaging the emitted, transmitted or reflected light from the grating device. The imaging system comprises an optical element, such as a cylindrical lens or a bended mirror, configured for focusing light in a transverse direction and for being invariant in an orthogonal transverse direction, the optical element being oriented such that the longitudinal direction of the grating device is oriented to coincide with the invariant direction of the optical element, and an imaging spectrometer comprising an entrance slit having a longitudinal direction oriented to coincide with the invariant direction of the optical element. The imaging spectrometer further comprises a 2-dimensional image sensor. The invention further relates to a method.

Disclosed are a sensor including a first metal layer and a second metal layer facing each other, and a volume changeable layer disposed between the first metal layer and the second metal layer and capable of absorbing a material to change the thickness thereof, wherein at least one of the first metal layer and the second metal layer is a semi-transmissive layer and the sensor indicates a color change by changing a resonance wavelength of light transmitted through the semi-transmissive layer according to a change in thickness of the volume changeable layer, and a sensor device, an electronic device, a smart window, and an IoT system including the same.

Methods and instruments for measuring a liquid sample (S1) in a well plate (50) by means of an optical chip 10. The chip (10) comprises an optical sensor (13) that is accessible to the liquid sample (S1) at a sampling area (SA) of the chip. A free-space optical coupler (11,12) is accessible to receive input light (L1) and/or emit output light (L2) via a coupling area (CA) of the chip (10). The sampling area (SA) of the chip 10 is submerged in the liquid sample (S1) while keeping the liquid sample (S1) away from the coupling area (CA) for interrogating the optical coupler (11,12) via an optical path (P) that does not pass through the liquid sample (S1).

The present invention provides a sensor comprising at least one whispering gallery mode resonator, wherein the resonator comprises a Bragg grating arranged over at least a portion of the perimeter of the resonator and wherein the resonator is selectively functionalized for the attachment of analyte receptors.

Disclosed herein is a method of determining a concentration of a subject based on fraction bound measurement. The method of determining a concentration of a subject based on fraction bound measurement may include fixing a ligand to a surface of an optical device, measuring a fraction bound of a subject to be detected based on an optical signal when the subject reacts to the ligand fixed to the surface of the optical device, and determining a relative value of a concentration of the subject based on a ratio of measured values of the fraction bounds of the subject and a reference signal.

Methods and instruments for measuring a liquid sample (S1) in a well plate (50) by means of an optical chip 10. The chip (10) comprises an optical sensor (13) that is accessible to the liquid sample (S1) at a sampling area (SA) of the chip. A free-space optical coupler (11,12) is accessible to receive input light (L1) and/or emit output light (L2) via a coupling area (CA) of the chip (10). The sampling area (SA) of the chip 10 is submerged in the liquid sample (S1) while keeping the liquid sample (S1) away from the coupling area (CA) for interrogating the optical coupler (11,12) via an optical path (P) that does not pass through the liquid sample (S1).

Methods and systems for analyzing a sample and generating a predictive model using cavity ring-down spectroscopy are disclosed. At least part of a sample is loaded in a ring-down cavity. For each of a set of wavelengths, a laser beam is generated and directed into the ring-down cavity. The laser beam entering the ring-down cavity is extinguished. Light intensity decay data for light exiting the ring-down cavity is registered via a light intensity sensor system. A probability is determined from the light intensity decay data for the set of wavelengths that a subject from which the sample was received has a physiological condition or a degree of the physiological condition at least indirectly using a dataset of light intensity decay data for previously analyzed samples for which the presence or the absence of the physiological condition or the degree of the physiological condition have been identified.

An optical microtoroid resonator including one or more nanoparticles attached to a surface of the resonator and capable of receiving an input signal from a far-field source (via free-space transmission) and outputting light propagating within the optical apparatus. A method for coupling light into and out of an optical resonator using a nanoparticle or nanoparticles to interface with spatially separated far-field optical elements.