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.

Methods include treating a portion of a sample composition to be tested for presence of an analyte by depleting or blocking the target analyte. The treated composition may be used to equilibrate an acoustic wave sensor prior to exposing the sensor to the untreated sample composition for analysis. By using the treated sample composition, in which the analyte is depleted or blocked, to equilibrate the sensor, the sensor may be equilibrated with a composition having a similar viscosity and non-specific binding characteristics to the untreated sample composition, which should result in improved accuracy when analyzing the analyte in the untreated sample composition.

A photoacoustic apparatus may include: a ring transducer configured to measure a photoacoustic signal generated from an object, and including a hollow space that is provided as a travel path of light and ultrasonic waves; a mirror part disposed along a light path of the light transmitted from the ring transducer, and configured to reflect the light transmitted from the ring transducer, and the ultrasonic waves generated from the object, and to adjust magnification of the mirror part according to a number of apertures of the photoacoustic apparatus; and a fluid tank including a transparent film that allows the photoacoustic signal to pass through the fluid tank, and accommodating a fluid, the ring transducer, and the mirror part inside the fluid tank.

In a first aspect, the invention relates to a photoacoustic gas sensor comprising a gas-fillable detection chamber and a reference chamber arranged laterally adjacent to each other and connected by a sensor channel. A sensor located at or in the sensor channel allows measurement of the photoacoustic signals. Both chambers are preferably located in a plane perpendicular to the emitted IR radiation of the IR emitter which is also comprised. The gas sensor is also formed from a multilayer substrate.

In further aspects, the invention also relates to a method of manufacturing a gas sensor and a method of analyzing gas with a gas sensor.

A photoacoustic gas sensor device for determining a value indicative of a presence or a concentration of a component in a gas comprises a measurement cell enclosing a measurement volume and a gas permeable area in the measurement cell for a gas to enter the measurement volume. An electromagnetic radiation source is arranged to emit electromagnetic radiation into the measurement volume, and a pressure transducer is arranged to measure a sound wave generated by the component in response to an absorption of electromagnetic radiation by the component in the measurement volume. In one aspect, the gas permeable area is represented by a porous gas permeable membrane with an average pore size of the porous gas permeable membrane between 10 nm and 1 μm. In another aspect the gas permeable area is represented by an area of the measurement cell containing holes reaching through an otherwise gas tight material of the measurement cell, with a diameter of the holes between 100 nm and 10 μm.

Methods include treating a portion of a sample composition to be tested for presence of an analyte by depleting or blocking the target analyte. The treated composition may be used to equilibrate an acoustic wave sensor prior to exposing the sensor to the untreated sample composition for analysis. By using the treated sample composition, in which the analyte is depleted or blocked, to equilibrate the sensor, the sensor may be equilibrated with a composition having a similar viscosity and non-specific binding characteristics to the untreated sample composition, which should result in improved accuracy when analyzing the analyte in the untreated sample composition.

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 system for measuring gas concentration includes a package having a cavity and a port, a photoacoustic gas sensor device within the package, and a Micro Electro Mechanical System (“MEMS”) valve separate from the photoacoustic gas sensor device placed over the port of the package and to allow ambient gas diffusion into the cavity in a first mode of operation, and to prevent ambient gas diffusion into the cavity and to acoustically isolate the cavity in a second mode of operation.

A photoacoustic sensor includes a first layer with an optical MEMS emitter; a second layer stacked over the first layer with a MEMS pressure pick-up and an optically transparent window, wherein the MEMS pressure pick-up and the optically transparent window are offset laterally with respect to one another; and a third layer stacked over the second layer with a cavity for a reference gas. The optical MEMS emitter transmits optical radiation along an optical path, wherein the optical path runs through the optically transparent window and the cavity for the reference gas, and wherein the MEMS pressure pick-up is outside the course of the optical path.

A photoacoustic gas sensor is provided. The photoacoustic gas sensor includes a hermetically sealed housing filled with a reference gas. Further, the photoacoustic gas sensor includes a microphone system arranged inside the housing. The microphone system is configured to generate a first microphone signal comprising a first signal component related to a photoacoustic excitation of the reference gas and a second microphone signal comprising a second signal component related to the photoacoustic excitation. The photoacoustic gas sensor additionally includes a circuit configured to generate an output signal based on the first microphone signal and the second microphone signal by destructively superimposing a third signal component of the first microphone signal related to mechanical vibrations of the photoacoustic gas sensor and a fourth signal component of the second microphone signal related to the mechanical vibrations.