A method for measuring a refractive index of a medium includes exciting a first antisymmetric resonance of a first metasurface, including a first periodic array of resonators formed on a substrate surface, with illumination incident on the first metasurface at a non-normal incidence angle with respect to the substrate surface, the first metasurface including the medium encapsulating the first periodic array of resonators. The method also includes determining a refractive index of the medium from a first amplitude of a first transmitted signal that includes a portion of the illumination transmitted through the first metasurface.

Provide herein is a refractometer, optically transmissive structure, and method of making. The structure has a first surface disposing a light source. A second surface is configured and disposed to provide an angular light reflective interface at, or proximate therewith, a fluid being sensed. A third surface disposes an optical sensor. The optically transmissive structure has at least one of the light source and the optical sensor directly incorporated, bonded, or adhered therewith or has at least one light blocker configured and disposed to block a portion of light being directed or reflected toward the third surface.

A method of investigating a sample (1) having an absorption within an infrared spectral range of interest, comprises the steps of creating measuring light (2) with a light source device (10), wherein the measuring light (2) includes wavelengths covering the infrared spectral range, directing the measuring light (2) through the sample (1) to a detector device (20) with a plurality of detector units (21), each of which comprising an infrared sensitive sensor section (22) and an associated metamaterial resonator section (23) having a specific spectral resonance line (3), wherein the spectral resonance lines (3) of the resonator sections (23) have different frequencies within the infrared spectral range, wherein the measuring light (2) is transmitted through the sample (1) to the resonator sections (23) and subsequently sensed by the sensor sections (22), wherein an output of each of the sensor sections (22) depends on the absorption of the sample (1) at the frequency of the spectral resonance line (3) of the associated resonator section (23), and providing at least one absorption characteristic of the sample (1) on the basis of the output of the sensor sections (22), wherein the sample (1) is arranged for providing near field coupling of electronic states of the sample (1) and photonic resonator states of the resonator sections (23), wherein, for each of the resonator sections (23), a resonance line attenuation is created, which is determined by a complex refractive index of the sample (1) at the frequency of the spectral resonance line (3) of the resonator section (23), and the output of each of the sensor sections (22) is determined by the resonance line attenuation of the associated resonator section (23). Furthermore, a spectrometer apparatus (100) for investigating a sample (1) is described, which has an absorption within an infrared spectral range of interest.

A system includes a light source configured to emit pulsed laser light, and a photodetection unit including a plurality of photoelectric conversion units arranged in a two-dimensional plane, wherein an emission timing of the light source and a detection timing of the photodetection unit are controlled by a timing control unit, wherein the photodetection unit detects scattered light on the two-dimensional plane, of the pulsed laser light emitted from the light source and entering an object, and wherein change of a refractive index of the object is estimated from change of light speed of the scattered light.

An observation apparatus includes a case having a transmissive window, an image sensor, an optical system, and a light source housed in the case, and an optical deflection unit. The optical system is configured to condense light incident inside the case to form an image of a sample inside a container. The light source is configured to emit light to the outside of the case without passing through the optical system. The optical deflection unit is configured to deflect light emitted to the outside of the case from the light source to a first direction proceeding toward the transmissive window. An angle of exit between the first direction and an optical axis of the optical system is different from an angle of incidence between a second direction in which light emitted to the outside of the case is incident on the optical deflection unit, and the optical axis.

The present disclosure describes a differential refractometer for gradient chromatography. In an exemplary embodiment, the differential refractometer includes a solvent delay volume, an eluent flow meter coupled to an eluent inlet of a sample cell, a solvent flow regulator coupled to an outlet of the solvent delay volume and coupled to a solvent inlet of a reference cell, an instrument controller configured to receive the eluent flow rate from the eluent flow meter, configured to receive the solvent flow rate from the solvent flow regulator, configured to receive a flow rate ratio from a flow rate ratio data source, wherein the flow rate ratio indicates a ratio of the eluent flow rate to the solvent flow rate, and an optical bench configured to measure a difference between a refractive index of the eluent present in the sample cell and a refractive index of the solvent present in the reference cell.

A flow cell includes a cell into which a liquid to be measured is introduced and is arranged so that a measurement light to be used for measuring an optical characteristic of the liquid enters one side of the cell and exits from the other side of the cell, an inlet for leading the liquid to flow into the cell, and an outlet for leading the liquid in the cell to flow out from the cell. The inlet and the outlet are provided to form an interface between a liquid flowing into the cell through the inlet and a liquid with which the cell has been already filled at two places on an optical path of the measurement light passing through the cell.

A fluid detection sensor includes: an optical sensor including a light emitting element array and a light receiving element array which are arranged on a substrate along a longitudinal direction thereof; a flow path member which includes a tubular body which is transparent and is arranged along the longitudinal direction facing the optical sensor, an inside of the tubular body constituting a flow path through which a plurality of substantially immiscible fluids flow as a slug flow; and a reflecting member placed on a side opposite to the optical sensor with respect to the flow path. The fluid detection sensor detects changes in light which occur in accordance with a movement of the plurality of fluids by the light receiving element array receiving light which is emitted by the light emitting element array toward the slug flow in the flow path and is reflected by the reflecting member.

A method is useable for determining a refractive index of an optical medium in a microscope, which has an objective facing toward a sample chamber. The optical medium is one of two optical media, which border two opposing surfaces of a cover slip or object carrier in the sample chamber and form two partially reflective interfaces, which are arranged at different distances from the objective. The method includes: deflecting a measurement light beam by the objective with oblique incidence on the cover slip or object carrier; generating two reflection light beams spatially separated from one another by the measurement light beam being partially reflected at each of the interfaces; receiving the two reflection light beams by the objective and conducting them onto a position-sensitive detector; registering intensities by the position-sensitive detector; and determining the refractive index of the optical medium based on the registered intensities.

Systems and methods for determining temperature or temperature related variables using a sensor having a measurement surface include a sensor body having one or more walls and containing an intermediary material, a window providing a measurement surface, a first temperature sensor obtaining a first temperature at or near the window, a second temperature sensor located within the intermediary material, and a processor configured to receive the first temperature and the second temperature and determine a temperature adjustment based on those temperatures. The temperature adjustment can be used to adjust a value of a temperature related variable based on the temperature at the measurement surface, for example for calculating a refractive index of a fluid. Additional temperature sensors may be included and further included in the determination of the temperature adjustment.