Modular photoacoustic detection device comprising: a photoacoustic cell including at least two chambers connected by at least two capillaries and forming a Helmholtz type differential acoustic resonator; acoustic detectors coupled to the chambers; a light source capable of emitting a light beam having at least one wavelength capable of exciting a gas intended to be detected and which can be modulated to a resonance frequency of the photoacoustic cell; a first photonic circuit optically coupling the light source to an input face of a first of the chambers; wherein the first photonic circuit is arranged in a detachable manner in a first housing formed in the acoustic cell and emerging on the input face of the first chamber.

A photoacoustic gas analyzer including a gas chamber to receive a gas sample, a radiation source to emit an electromagnetic radiation adapted to excite N different types of gas molecules in the gas sample, the concentrations of which are to be determined, an acoustic-wave sensor to detect acoustic waves generated by the irradiated gas, and a control unit. The control unit controls the radiation source to emit electromagnetic radiation with a time-varying intensity and to modulate the frequency at which the intensity is varied with a modulation signal having at least N different values, to receive from the acoustic-wave sensor signals indicative of acoustic waves generated by the irradiated gas, to determine at least N mutually different signal amplitudes each associated with a respective N mutually different frequencies at which the intensity of the emitted electromagnetic radiation is varied, and to determine the concentrations of the N different gas types.

The invention relates, in a first aspect, to a photoacoustic spectroscope for analyzing gas, comprising an infrared emitter (3), which can be modulated, an analysis volume (1), which can be filled with gas, and a sound pressure detector. The sound pressure detector comprises a structure (5) capable of vibrating, an actuator and a measurement unit, wherein the actuator is configured to actively excite vibration of the structure (5) capable of vibrating and the measurement unit can measure the vibration properties of the structure (5) capable of vibrating, which measurement depends on the formation of the sound pressure waves. In an additional aspect, the invention relates to a method for analyzing gas, comprising the provision of a photoacoustic spectroscope for analyzing gas, irradiating the gas with infrared radiation, modulated by a modulation frequency, to generate sound pressure waves, exciting the structure (5) capable of vibrating at an excitation frequency, measuring the vibration properties of the structure (5) capable of vibrating, which measurement depends on the sound pressure, and determining the sound pressure of the gas based on the measured vibration properties.

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.

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.

A photoacoustic apparatus includes a light irradiation unit configured to irradiate a subject with light a plurality of times; a driving unit configured to move a supporting member so that relative positions of the supporting member and the subject differ at each of the plurality of times; a plurality of transducers configured to receive acoustic waves generated through the plurality of times of irradiation and output a plurality of groups of reception signals corresponding to the plurality of times of irradiation; the supporting member configured to support the transducers such that directional axes of at least some of the transducers converge; a first memory configured to store the groups of reception signals; and a processing unit configured to obtain subject information at a target position by assigning, to each of the groups of reception signals, a weight corresponding to relative positions of the supporting member and the target position.

In a first aspect, the invention relates to a method for producing a gas-filled reference chamber which is hermetically sealed. Thereby, the gas with which the reference chamber is filled is introduced via an opening in a separate coating chamber only after bonding of the wafers forming the reference chamber. The reference chamber preferably contains MEMS devices.

In another aspect, the invention relates to a photoacoustic gas sensor comprising such a reference chamber within which a MEMS sensor is present.

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 downhole system includes a quartz enhanced photoacoustic spectrometer (QEPAS) configured to be positioned within a wellbore formed in a subterranean zone of a hydrocarbon formation, a sampling system coupled to the QEPAS, and a computer system connected to the QEPAS. The sampling system is configured to be positioned in the wellbore and obtain a sample of a wellbore fluid at a downhole location in the subterranean zone. The QEPAS is configured to spectroscopically scan the sample and to determine a plurality of quantities of a corresponding plurality of hydrocarbons in the same. The computer system includes one or more processors to perform operations including receiving the plurality of quantities of the plurality of hydrocarbons in the sample and determining a plurality of ratios, where each ratio is a ratio of one of the plurality of hydrocarbons with another of the plurality of hydrocarbons.

There is provided a method for sensing a sample. The method includes the following steps: first a light beam is directed onto the sample. The sample transmits at least a portion of the light beam to form a transmitted light beam. Next, the transmitted light beam is received at an acoustic transducer. The acoustic transducer absorbs at least a portion of the transmitted light beam and in response generated an acoustic wave. Subsequently, an electrical signal is generated at the acoustic transducer. The electrical signal is generated based on at least a portion of the acoustic wave.