Abstract: According to an aspect there is provided an apparatus for Raman light detection, said apparatus comprising: an illumination unit, configured to provide a wavelength modulation for generating and outputting wavelength modulated laser light towards a sample for inducing generation of Raman scattered light from the sample; a wavelength filter for filtering the Raman scattered light; and a light detector, configured to receive the Raman scattered light filtered by the wavelength filter and to provide an instantaneous response signal dependent on an intensity of the received Raman scattered light.

Abstract: There is provided an apparatus for Raman spectroscopy comprising: a tunable laser configured to output laser light towards a sample for inducing Raman scattered light from the sample, wherein a wavelength of the laser light is tunable; a light collecting and filtering arrangement configured to collect the Raman scattered light in a collection angle from the sample, wherein the arrangement provides the Raman scattered light as incident light onto a narrow bandpass filter comprising a transmission band with a FWHM of 0.2 nm, and preferably 0.02 nm or less, and wherein an angle of incidence of the incident light is matched to a filter acceptance angle of the bandpass filter; and a light detector, configured to receive the Raman scattered light filtered by the arrangement and to detect the Raman scattered light. The apparatus is configured to scan the wavelength of the laser light and to detect the intensity of the Raman scattered light by the light detector for forming a Raman spectrum of the sample.

Abstract: A method for pre-processing of images for machine learning, comprises: receiving images to be pre-processed, wherein each image represents information in an array of pixels providing spatial information of the image, wherein each pixel is represented by a plurality of light intensities in at least four different wavelength channels providing multi-spectral information; and forming a histogram representation of each image by determining a plurality of histogram values, wherein each histogram value represents a set of wavelengths and a set of light intensities and the histogram value corresponds to a number of pixels in the array being assigned to the set of light intensities for the set of wavelengths.

Abstract: According to an aspect of the present inventive concept there is provided a probe for analysis of a liquid in a mixture of the liquid and solid substance. The probe comprises: a tube comprising a sample end configured to be inserted into the mixture; a cap configured to come into contact with the mixture at the sample end, the cap comprising one or more openings configured for allowing passage of the liquid therethrough, and for preventing passage of the solid substance therethrough; and an optical measurement head arranged in the tube and configured to come into contact with the liquid having passed the one or more openings, wherein the optical measurement head is configured to collect measurement information for analysis of the liquid.

Abstract: A device for dielectric material characterization of a test sample is provided. The device comprises a resonator block comprising a groove at at least one side of the resonator block, wherein the groove comprises at least a first inclined surface and a second inclined surface and is configured to contact the test sample via the first inclined surface and/or the second inclined surface. In this regard, the resonator block is configured to generate a rotational electric field coupled between the first inclined surface and the second inclined surface of the groove and further to propagate the rotational electric field partially or fully through the test sample in order to perform dielectric material characterization of the test sample.

Abstract: A sensing device and a method for sensing an electrical property of a test sample is provided. The sensing device includes a substrate, and a closed loop resonator and an open loop resonator arranged on the substrate, and are arranged in a cascade configuration, the open loop resonator including a first loop end and a second loop end arranged at an edge of the substrate and are configured to be in contact with the test sample. In this regard, the closed loop resonator is configured to couple in an input excitation and to transfer the input excitation towards the open loop resonator. Furthermore, the open loop resonator is configured to generate localized electric fields between the first loop end and the second loop end propagating through the test sample.

Abstract: A device for dielectric material characterization of a test sample is provided. The device comprises a resonator block comprising a groove at at least one side of the resonator block, wherein the groove comprises at least a first inclined surface and a second inclined surface and is configured to contact the test sample via the first inclined surface and/or the second inclined surface. In this regard, the resonator block is configured to generate a rotational electric field coupled between the first inclined surface and the second inclined surface of the groove and further to propagate the rotational electric field partially or fully through the test sample in order to perform dielectric material characterization of the test sample.

Abstract: According to an aspect of the present inventive concept there is provided a probe for analysis of a liquid in a mixture of the liquid and solid substance. The probe comprises: a tube comprising a sample end configured to be inserted into the mixture; a cap configured to come into contact with the mixture at the sample end, the cap comprising one or more openings configured for allowing passage of the liquid therethrough, and for preventing passage of the solid substance therethrough; and an optical measurement head arranged in the tube and configured to come into contact with the liquid having passed the one or more openings, wherein the optical measurement head is configured to collect measurement information for analysis of the liquid.

Abstract: A circuit for optoelectronic down-conversion of a terahertz, THz, signal comprises a first photodiode and a second photodiode configured to be excited by an optical beat signal. The photodiodes are coupled in series through a common antenna. The terminals of the antenna are coupled to form an output terminal and the antenna is configured to receive the terahertz, THz, signal. The photodiodes thereby, via the optical beat signal, respectively, down-convert the THz signal and generate a current comprising an intermediate frequency, IF, component and a direct current, DC, component. The respective generated currents are summed at the output terminal, thereby obtaining the IF components and cancelling the DC components.

Abstract: A circuit for optoelectronic down-conversion of a terahertz, THz, signal comprises a first photodiode and a second photodiode configured to be excited by an optical beat signal. The photodiodes are coupled in series through a common antenna. The terminals of the antenna are coupled to form an output terminal and the antenna is configured to receive the terahertz, THz, signal. The photodiodes thereby, via the optical beat signal, respectively, down-convert the THz signal and generate a current comprising an intermediate frequency, IF, component and a direct current, DC, component. The respective generated currents are summed at the output terminal, thereby obtaining the IF components and cancelling the DC components.

Abstract: A solid-state device for photo detection, in general, of terahertz radiation is disclosed. One aspect is a detector device comprising a body having a photoconductive material, a first antenna element connected to a first portion of the body, and a second antenna element connected to a second portion of the body. The first antenna element and the second antenna element are arranged to induce an electric field in the body in response to an incident signal. Further, the device has a waveguide arranged to couple light into the photoconductive material via a coupling interface between the waveguide and the body, where the coupling interface faces away from the first portion and the second portion of the body and is closer to the first portion than to the second portion.

Abstract: A solid-state device for photo detection, in general, of terahertz radiation is disclosed. One aspect is a detector device comprising a body having a photoconductive material, a first antenna element connected to a first portion of the body, and a second antenna element connected to a second portion of the body. The first antenna element and the second antenna element are arranged to induce an electric field in the body in response to an incident signal. Further, the device has a waveguide arranged to couple light into the photoconductive material via a coupling interface between the waveguide and the body, where the coupling interface faces away from the first portion and the second portion of the body and is closer to the first portion than to the second portion.

Abstract: The disclosed technology generally relates to sensors comprising a two-dimensional electron gas (2DEG), and more particularly to an AlGaN/GaN 2DEG-based sensor for sensing signals associated with electrocardiograms, and methods of using the same. In one aspect, a sensor comprises a substrate and a GaN/AlGaN hetero-junction structure formed on the substrate and configured to form a two-dimensional electron gas (2DEG) channel within the GaN/AlGaN hetero-junction structure. The sensor additionally comprises Ohmic contacts connected to electrical metallizations and to the 2DEG channel, wherein the GaN/AlGaN hetero-junction structure has a recess formed between the Ohmic contacts. The sensor further comprises a dielectric layer formed on a top surface of the sensor.

Abstract: The disclosed technology generally relates to a sensor and methods for making and using the same, and more particularly relates to a sensor configured to sense the presence of at least one fluidum. In one aspect, a sensor for sensing a fluidum in a space adjoining the sensor comprises a two-dimensional electron gas (2DEG) layer stack. The sensor additionally comprises a gate lying adjacent to at least part of the 2DEG layer stack and configured to electrostatically control the electron density of a two-dimensional electron gas (2DEG) in the 2DEG layer stack. The sensor further comprises a source electrode contacting the 2DEG layer stack for electrically contacting the 2DEG.

Abstract: The application describes methods and apparatus for chemical sensing, e.g. gas sensing, which have high sensitivity but low power operation. A sensor is described having a flexible membrane comprising a III/N heterojunction structure configured so as to form a two dimensional electron gas within said structure. A sensing material is disposed on at least part of the flexible membrane, the sensing material being sensitive to one or more target chemicals so as to undergo a change in physical properties in the presence of said one or more target chemicals. The sensing material is coupled to said heterojunction structure such that said change in physical properties of the sensing material imparts a change in stress within the heterojunction structure which modulates the resistivity of the two dimensional electron gas.

Abstract: A Sensor for sensing the presence of at least one fluidum in a space adjoining the sensor is disclosed. In one aspect, the sensor has a two-dimensional electron gas (2DEG) layer stack, a gate electrode overlaying at least part of the 2DEG layer stack for electrostatically controlling electron density of a 2DEG in the 2DEG layer stack and a source and a drain electrode contacting the 2DEG layer stack for electrically contacting the 2DEG, wherein a detection opening is provided in between the gate electrode and the 2DEG layer stack and wherein the detection opening communicates with the space through a detection opening inlet such that molecules of the fluidum can move from the adjoining space through the detection opening inlet into the detection opening where they can measurably alter a electric characteristic of the 2DEG.

Abstract: The disclosed technology generally relates to sensors comprising a two-dimensional electron gas (2DEG), and more particularly to an AlGaN/GaN 2DEG-based sensor for sensing signals associated with electrocardiograms, and methods of using the same. In one aspect, a sensor comprises a substrate and a GaN/AlGaN hetero-junction structure formed on the substrate and configured to form a two-dimensional electron gas (2DEG) channel within the GaN/AlGaN hetero-junction structure. The sensor additionally comprises Ohmic contacts connected to electrical metallizations and to the 2DEG channel, wherein the GaN/AlGaN hetero-junction structure has a recess formed between the Ohmic contacts. The sensor further comprises a dielectric layer formed on a top surface of the sensor.

Abstract: The disclosed technology generally relates to a sensor and methods for making and using the same, and more particularly relates to a sensor configured to sense the presence of at least one fluidum. In one aspect, a sensor for sensing a fluidum in a space adjoining the sensor comprises a two-dimensional electron gas (2DEG) layer stack. The sensor additionally comprises a gate lying adjacent to at least part of the 2DEG layer stack and configured to electrostatically control the electron density of a two-dimensional electron gas (2DEG) in the 2DEG layer stack. The sensor further comprises a source electrode contacting the 2DEG layer stack for electrically contacting the 2DEG.

Abstract: The present disclosure relates to a gas sensor including a first layer and a second layer superimposed on each other along an interface between the two layers. The first layer includes an array of nanoparticles along the interface, the nanoparticles provided so as to allow, upon illumination with electromagnetic radiation, long range diffractive coupling of surface plasmon resonances resulting in a surface lattice resonance condition. The second layer includes a material that, when exposed to at least one predetermined gas, detectably affects the surface lattice resonance condition. The material of the second layer preferably has a porosity of at least 10%.

Abstract: Methods and sensors for detecting the presence and/or concentration of an analyte are disclosed. In one aspect, a sensing element for use in a sensor is disclosed. The sensing element comprises a resonant cavity device configured to emit optical radiation at an initial power level, a sensing layer exhibiting an initial refractive index, and a detector. The sensing layer is configured to absorb or adsorb an analyte and, in response to absorbing or adsorbing the analyte, exhibit a modified refractive index that differs from the initial refractive index. The resonant cavity device is further configured to, in response to the sensing layer absorbing or adsorbing the analyte, emit optical radiation at a modified power level based on the modified refractive index. The detector is configured to detect the modified power level.