A system is used to excite an object at a vibration frequency, in order to induce stationary or travelling waves having the vibration frequency on the surface of the object. An optical interferometer is configured to use optical interference to determine vibration amplitude and phase data of the stationary or travelling wave at each of a plurality of points on the surface, relative to a reference phase. A processing system is used to apply a spatial derivative filter to the vibration phase data, and the resulting spatial-derivative-of-phase data is processed to determine a property of the object, and is further processed to generate graphical-representation data for outputting on a display device.

A photoacoustic detection system (20) includes a detector (22) that has a chamber (24), a pulsed light source (26), piezoelectric tuning forks (28), and a photosensor (30). The chamber has an inlet and an outlet for flow of an analyte. The pulsed light source is adjacent the chamber and is operable to emit a light beam along a path through the chamber. The tuning forks are arranged along the path, and each of the tuning forks is operable to emit first sensor signals. The photosensor is arranged along the path and is operable to emit second sensor signals. A controller (38) is connected to receive the first and second sensor signals. The controller is configured to determine whether a target species is present in the analyte based on the first sensor signals and determine whether the target species is present in the analyte based on the second sensor signals.

Provided are an optical sensor device using surface acoustic waves and an optical sensor device package. The optical sensor device includes: a substrate including a first light sensing area and a temperature sensing area and including a piezo electric material; a first input electrode and a first output electrode which are disposed in the first light sensing area and are apart from each other with a first delay gap therebetween; a first sensing film overlapping the first delay gap and configured to cover at least some portions of the first input electrode and the first output electrode; and a second input electrode and a second output electrode which are disposed in the temperature sensing area and are apart from each other with a second delay gap therebetween. The second delay gap is exposed to air.

A detector module is disclosed. In one example, the detector module is for a photo-acoustic gas sensor and comprises a first substrate made of a semiconductor material and comprising a first surface and a second surface opposite to the first surface, a second substrate comprising a third surface, a fourth surface opposite to the third surface, and a first recess formed in the fourth surface. The second substrate is connected with its fourth surface to the first substrate so that the first recess forms an airtight-closed first cell which is filled with a reference gas and a pressure sensitive element comprising a membrane disposed in contact with the reference gas. The detector module is further configured such that a beam of light pulses passes through the first substrate and thereby enters the first cell.

Certain embodiments of the present disclosure are directed to a method that may include identifying at least one metric for a fluid flowing through a line from a vessel to a dispenser. The method may include identifying a reference value for the at least one metric for the fluid. The method may include performing an analysis of the fluid based on the at least one metric for the fluid. The method may include comparing results of the analysis with the reference value. The method may include performing at least one action based on determining that there has been a change in the at least one metric relative to the reference value.

A thermoacoustic probe with an electromagnetic (EM) energy applicator, a thermoacoustic transducer, and a housing containing the applicator and thermoacoustic transducer and enabling an EM exit window and a transducer front face to be held flush with respect to each other. A first acoustic absorbing material is placed between the EM applicator and the transducer, between the EM applicator and the housing, and between the transducer and the housing as spacers; and a second acoustic absorbing material is injected between the EM applicator and the transducer, between the EM applicator and the housing, and between the transducer and the housing in the spaced gaps, wherein the first acoustic absorbing material and the second acoustic absorbing material are combined to form a sleeve covering the applicator sides and the transducer sides. The acoustic absorbing materials mitigate sound artifacts and noise resulting in cleaner signal data. In a preferred embodiment the applicator is a radio-frequency applicator, the transducer is a piezoelectric transducer, and the probe is utilizable for tissue imaging.

A photoacoustic detection system includes a detector that has a chamber, a pulsed light source, piezoelectric tuning forks, and a photosensor. The chamber has an inlet and an outlet for flow of an analyte. The pulsed light source is adjacent the chamber and is operable to emit a light beam along a path through the chamber. The tuning forks are arranged along the path, and each of the tuning forks is operable to emit first sensor signals. The photosensor is arranged along the path and is operable to emit second sensor signals. A controller is connected to receive the first and second sensor signals. The controller is configured to determine whether a target species is present in the analyte based on the first sensor signals and determine whether the target species is present in the analyte based on the second sensor signals.

A detector cell for a photoacoustic gas sensor comprises a first layer structure, a second layer structure arranged at the first layer structure and comprising a membrane structure, and a third layer structure arranged at the second layer structure. The first layer structure and the third layer structure hermetically enclose a cavity, wherein the membrane structure is arranged in the cavity.

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.

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.