A sensor for photoacoustic spectroscopy including a support and a mechanical resonator fastened to the support, including at least one sensor element designed to be vibrated by an acoustic wave, and at least one first capacitive electrode mechanically coupled to the sensor element so as to be moved by the sensor element when it is vibrated; and at least one second capacitive electrode forming with the at least one first electrode, a capacitive sensor; the support facing the sensor element, an apertured part formed by one or more through-openings. Also provided is a detection and/or measurement device and method, for photoacoustic spectroscopy, using such a sensor.

A detector comprises an optical parametric oscillator having a non-linear material adapted to convert via a parametric process pump light into down converted light of two different wavelengths, the first wavelength being longer than the second wavelength. The non-linear material is provided in a down converted wave cavity arranged to resonate only one of the first or second wavelengths. The detector comprises means for modulating light in the down converted wave cavity to induce an acoustic or pressure wave caused by absorption of the resonant one of the first and second wavelengths. The detector further comprises means located in the down-converted wave cavity for detecting the acoustic or pressure wave. The detector may be used for detecting or sensing very low levels of a fluid, for example a gas such as ethane.

A fluid sensor includes a housing structure forming a cavity for an IR emitter for emitting an IR radiation in the cavity, wherein the IR radiation has a center wavelength for providing an interaction of the IR radiation with the target fluid resulting in a temperature change in the cavity or in the housing structure, which effects a mechanical pulse in the housing structure, and an inertial detection sensor mechanically coupled to the housing structure for sensing the mechanical pulse in the housing structure.

A photoacoustic measurement setup having an infrared radiator that is suitable for radiating broadband light with periodically modulated energy/intensity. The infrared radiator is configured to change an excitation spectra of a radiated broadband light, and a gas volume is heated by the radiated broadband light to generate an acoustic wave within the gas volume. The photoacoustic measurement setup also includes an acoustic sensor, which is suitable for measuring the acoustic wave generated in the gas volume.

A photoacoustic detector includes an emitter, an acoustic resonator having a single-pass cavity with a transparent wall, and an acoustic sensor. The emitter is arranged adjacent to the transparent wall and is configured to emit modulated electromagnetic radiation that enters the acoustic resonator through the transparent wall in a direction that intersects with a longitudinal axis of the cavity.

A thermal emitter includes a freestanding membrane supported by a substrate, wherein the freestanding membrane includes in a lateral extension a center section, a conductive intermediate section and a border section, wherein the conductive intermediate section laterally surrounds the center section and is electrically isolated from the center section, the conductive intermediate section including a conductive semiconductor material that is encapsulated in an insulating material, wherein the border section at least partially surrounds the intermediate section and is electrically isolated from the conductive intermediate section, and wherein a perforation is formed through the border section.

Methods, apparatuses, and systems for providing a sealed glass enclosure for a gas detecting apparatus are provided. An example method may include: preparing a controller component that is operatively coupled to a sensing element, wherein the controller component comprises at least one electrical connector; joining a first glass component and a second glass component to form a unitary body such that the at least one electrical connector is disposed therebetween; preparing a glass tube comprising an open surface; disposing the controller component and sensing element within the glass tube; positioning the unitary body comprising the first glass component and the second glass component adjacent the open surface of the glass tube; and encapsulating the unitary body to the glass tube to form the sealed glass enclosure.

A system for detecting a concentration of free SiO.sub.2 in coal dust includes a first sampling tube and a second sampling tube for sampling the coal dust, a three-way control valve communicated with the first sampling tube and the second sampling tube respectively, a photoacoustic spectrometry detection device communicated with the three-way control valve through a connecting pipeline, and a SiO.sub.2 reaction tube for reacting SiO.sub.2 in the coal dust; and the SiO.sub.2 reaction tube is disposed on the second sampling tube. In the present disclosure, a coal dust sampling line is convenient to change by disposing the three-way control valve, and the first sampling tube and the second sampling tube are respectively communicated with the photoacoustic spectrometry detection device, so as to perform a differential accurate detection of the reacted CO content, and to obtain the SiO.sub.2 content.

Provided is a sensor system having an improved SNR. The sensor system (1) includes: a sensor (gas sensor 10) including a light-emitting element (11) and a detecting element (light-receiving element 12) that detects a signal that is based on light emitted from the light-emitting element; and a computation device (20) that, by taking an interval in which the light-emitting element emits light as an ON interval and an interval in which the light-emitting element does not emit light as an OFF interval, uses the signal as detected in the ON interval and the signal as detected in a plurality of the OFF interval to compute one measurement value.

A photoacoustic gas sensor device is proposed for determining a value indicative of a presence or a concentration of a component in a gas. The photoacoustic gas sensor device comprises a substrate, and a measurement cell body arranged on a first side of the substrate. The substrate and the measurement cell body define a measurement cell enclosing a measurement volume. The measurement cell comprises an aperture for a gas to enter the measurement volume. The device further comprises an electromagnetic radiation source for emitting electromagnetic radiation, and a microphone for measuring a sound wave generated by the component in response to an absorption of electromagnetic radiation by the component. The electromagnetic radiation source and the microphone are arranged on the first side of the substrate and in the measurement volume. The microphone has a bottom port facing the substrate, and the measurement volume is communicatively coupled to the bottom port.