A device for optical detection of analytes in a sample includes at least two optoelectronic components. The optoelectronic components include at least one optical detector configured to receive a photon and at least one optical emitter configured to emit a photon. The at least one optical emitter includes at least three optical emitters disposed in a flat, non-linear arrangement, and the at least one optical detector includes at least three optical detectors disposed in a flat, non-linear arrangement. The at least three optical emitters and the at least three optical detectors include at least three different wavelength characteristics.

A computer-implemented method includes controlling an instrument to measure a fluorescence emission spectrum of a sample including a first peak emission wavelength and at least a second peak emission wavelength, emitted in response to an excitation wavelength and controlling the instrument to measure an absorbance obtained at the excitation wavelength of the sample. The method may include determining, using the computer, a ratio of the measurements at either the second peak emission wavelength, or a sum of measurements at a plurality of peak emission wavelengths including at least the first peak emission wavelength and the second peak emission wavelength, to the first peak emission wavelength, and calculating, using the computer, a value for a quality parameter based on a combination of at least the ratio and the absorbance measurement. The method may include controlling an associated process based on the quality parameter.

A method is provided for degradation-compensated evaluation of detection signals of a sensor arrangement operating on the principle of luminescence quenching, which arrangement has a luminophore that degrades over time, an excitation radiation source, and at least one optical sensor. The luminophore radiates, in accordance with a response characteristic of the sensor arrangement, in reaction to irradiation with a predefined modulated excitation radiation and as a function of the extent of an interaction of the luminophore with a quencher substance that quenches the luminescence of the luminophore. A response radiation is detected by the at least one optical sensor. The sensor arrangement outputs a detected intensity value representing an intensity of the response radiation and a detected phase value representing a phase difference of the response radiation with respect to the modulation of the excitation radiation. A predetermined calibration value correlation is identified in consideration of the reference response characteristic.

A material evaluating device for an agricultural work machine comprising: a light source for illuminating one or more constituent materials to be examined; a spectrometer for providing a spectral signal related to the wavelength-specific intensity of light reflected by the constituent materials; and an evaluation device configured to determine the content of one or more constituent materials using the spectral signal of the spectrometer and a calibration data, wherein a property signal relating to a property of the one or more constituent materials is supplied to the evaluation device and the evaluation device is configured, using the property signal, to determine the content of the one or more constituent materials.

A differential nondispersive infrared (NDIR) sensor incorporates an infrared (IR) chopper and multiple multi-bit digital registers to store and compare parameter ratio values, as may be digitally calibrated to corresponding temperature values, from chopper clock cycle portions in which a plasmonic MEMS detector is irradiated by the IR chopper with such values from chopper clock cycle portions in which the IR detector is not irradiated by the IR chopper. The plasmonic MEMS detector is referenced to a reference MEMS device via a parameter-ratio engine. The reference device can include a broadband IR reflector or can have a lower-absorption metasurface pattern giving it a lower quality factor than the plasmonic detector. The resultant enhancements to accuracy and precision of the NDIR sensor enable it to be used as a sub-parts-per-million gas concentration sensor or gas detector having laboratory, commercial, in-home, and battlefield applications.

A spectral imaging system configured to obtain spectral measurements in a plurality of spectral regions is described herein. The spectral imaging system comprises at least one optical detecting unit having a spectral response corresponding to a plurality of absorption peaks of a target chemical species. In an embodiment, the optical detecting unit may comprise an optical detector array, and one or more optical filters configured to selectively pass light in a spectral range, wherein a convolution of the responsivity of the optical detector array and the transmission spectrum of the one or more optical filters has a first peak in mid-wave infrared spectral region between 3-4 microns corresponding to a first absorption peak of methane and a second peak in a long-wave infrared spectral region between 6-8 microns corresponding to a second absorption peak of methane.

An example CO.sub.2 monitoring systems is configured for monitoring levels of CO.sub.2 in a wellbore. A CO.sub.2 monitoring system may include one or more laser monitoring tools. A laser monitoring tool may include an optical element to output a laser beam, a detector to receive the laser beam, a first chamber housing the optical element and detector, and a second chamber including an inlet and an outlet receive and release, respectively, wellbore fluid. The first chamber may be in fluid connection with second chamber via a gas permeable membrane. Gas may permeate from second chamber into first chamber. Gas in the first chamber is subjected to a laser beam. Absorption of light by the gas is measured, and content of gas is determined based at least in part on the amount of light absorption by the gas.

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.

An on-chip spectroscopic sensor includes a tunable diode laser. A laser driver for drives the tunable diode laser. An analyte test cavity receives a chemical sample and exposes the received chemical sample to light from the tunable diode laser. An optical detector detects light emerging from the analyte test cavity as a result of the laser exposure. A spectral analyzer determines a spectrum of the emerging light, matches and removes one or more known optical fringe patterns from the determined spectrum, and determines a composition or concentration of the chemical sample from the optical fringe pattern-removed spectrum.

A measuring method for measuring dissolved oxygen includes performing a first measurement sequence, including: emitting a first stimulation signal onto a sensor for a first period; detecting a first detection signal; determining a phase shift between the first stimulation signal and the first detection signal; and calculating a first measured value based on the determined phase shift. Performing a second measurement sequence, including a second stimulation signal onto the sensor for a second period, wherein the second stimulation signal is different than the first stimulation signal; detecting a second detection signal; determining a decay time of the second detection signal; calculating a second measured value based on the decay time. The method further includes comparing the first measured value to the second measured value and correcting the first measured value when a difference between the first measured value and the second measured value is greater than a first limit value.