A photoacoustic gas analyzer, including: a gas chamber to receive a gas to be analyzed; a radiation source that emits into the gas chamber electromagnetic radiation with a time-varying intensity to excite gas molecules of N mutually different gas types the concentrations of which are to be determined in the received gas, wherein the radiation source is operable in N mutually different modes, each mode having a unique emission spectrum different from the emission spectra of the other N1 modes; an acoustic-wave sensor that detects acoustic waves generated by the electromagnetic radiation emitted into the gas to be analyzed; and a control unit to operate the radiation source in the different modes respectively to emit electromagnetic radiation with a time-varying intensity; to receive in each mode from the acoustic-wave sensor signals; and to determine from the signals received in each mode the concentrations of the N mutually different gas types.

The invention relates to a micro cantilever beam sensor and making method, including a chip, and its character: there is at least a group of sensor cells set on the chip, where the sensor cell is composed of the completely same four force-sensitive resistors composing a Wheatstone bridge and two cantilever beams, two of these resistors are on the substrate of the chip, the other two are on the two cantilever beams, respectively, one cantilever beam acts on a measuring cantilever beam and the other one acts on a reference cantilever beam, and the measuring cantilever beam is set with a sensitive layer on the surface. It can design and prepare in a liquid-flow micro-tank by front etching and silicon-glass bonding techniques, to directly detect liquid biomolecule. Whether applied to gas sensor or biosensor, it will play an important role in reducing device size, enhancing device sensitivity and realizing sensor multi-functionality. It has wide prospects for the fields of environment monitoring, clinic diagnosis and therapy, new drug development, food safety, industrial processing control, military and so on.

An electric measurement circuit possesses an electrical reaction leg for forming an oscillator from a resonator, and furthermore possesses a measurement leg the input of which is supplied by the electrical reaction leg. The measurement leg contains an adjustable phase shifter so that an additional excitation force that is applied to the resonator in the measurement leg can be adjusted in phase quadrature with respect to an excitation force that is applied to the resonator in the electrical reaction leg. Such an electrical measurement circuit is particularly suitable for forming a photoacoustic gas detector.

An example of a system comprises a volume filled with a gas, a gas excitation device configured to excite the gas inside the volume, a microphone configured to output a microphone signal on the basis of the gas excited by the gas excitation device, and a testing unit configured to take the microphone signal as a basis for testing a gas-tightness of the volume. An example of a photoacoustic sensor comprises a hermetically sealed sensor cell, a gas excitation device and a testing unit configured to take the microphone signal dependent on the thermally excited gas as a basis for testing a gas-tightness of the sensor cell. One example comprises a method for testing a gas-tightness of a volume filled with a gas.

A MEMS photoacoustic gas sensor includes a first membrane and a second membrane opposing the first membrane and spaced apart from the first membrane by a sensing volume. The MEMS photoacoustic gas sensor includes an electromagnetic source and communication with the sensing volume to deflect the first membrane and the second membrane.

An element of a photoacoustic sensor combines an optomechanical resonator and a photoacoustic cavity. The photoacoustic cavity is formed by a measurement chamber, traversed by a pulsed excitation beam. The optomechanical resonator is formed by an optical resonator, a mechanical element for being set in rapid oscillations, by an optical signal confined in the optomechanical resonator, and in slow oscillations, by an acoustic wave generated in the photoacoustic cavity. A measurement beam is sent into the optical resonator, where it carries out several passages via the mechanical element. The optical properties thereof at the output of the optical resonator are therefore dependent on the oscillations of the mechanical element. A low-frequency-amplitude-modulated high-frequency signal can be obtained, with the amplitude modulation representing the acoustic wave in the measurement chamber. An accurate, low-noise, and highly compact method is enabled for making measurements with a photoacoustic effect.

A photoacoustic flow cell, the components of which may be made well in advance of conducting photoacoustic analysis, comprising (a) a chamber structure that defines a chamber, a chamber inlet, and a chamber outlet, and (b) a glass test structure, at least a portion of which is supported by the chamber structure and at least a portion of which is located in the chamber, wherein the test structure comprises an interior surface that defines a test passageway through which samples will be flowed when conducting the photoacoustic analysis.

Disclosed is an apparatus for and method of measuring the concentration of F2 in the laser gas used in an excimer laser. Quartz Enhanced Photoacoustic Spectroscopy is used to obtain a direct measurement of F2 concentration quickly and using only a small sample volume.

The invention relates to a device (1) and a corresponding method for mid-infrared microscopy and/or analysis, the device (1) comprising at least one radiation unit (10) configured to generate radiation (11) of time-varying intensity, the radiation (11) comprising one or more wavelengths in the mid-infrared spectral range, at least one refractive and/or reflective optical unit (12) which is configured to focus and/or direct the radiation (11) to at least one region or point of interest (20) located on and/or within an object (2), at least one detection unit (18) configured to detect ultrasound waves (17) emitted by the object (2) at the at least one region or point of interest (20) in response to an interaction of the radiation (11) with the object (2) and to generate according detection signals, and an evaluation unit (25) configured to derive information regarding at least one property of the object (2) from the detection signals and/or to generate a spatial and/or spatio-temporal distribution of the detection signals or of information derived from the detection signals obtained for the at least one region or point of interest (20) located on and/or within the object (2).

A fluid sensor includes a housing and a thermal emitter in the housing to emit first thermal radiation into a detection volume of the housing at a first power level during a measurement interval and emit the first thermal radiation at a reduced first power level or not emit said first thermal radiation at all during an intermediate interval disposed outside of the measurement interval. The fluid sensor includes a measuring element in the detection volume to receive a radiation signal during the measurement interval. The fluid sensor includes a second thermal emitter in the housing to emit second thermal radiation at a second power level into the detection volume during the intermediate interval such that a thermal oscillation of thermal radiation in relation to an overall power level of the thermal radiation in the detection volume is at most 50% during the measurement interval and the intermediate interval.