Apparatus and method for in-situ calibration of a photoacoustic sensor

An apparatus for in-situ calibration of a photoacoustic sensor, the apparatus comprising:

• a calibration unit configured to control a signal generator such that the signal generator feeds an infrared (IR) emitter with an electric pulse;
• and
• a sensor configured to measure a physical characteristic of a surface of the IR emitter, wherein the physical characteristic of the IR emitter depends on the electric pulse,
• wherein the calibration unit is configured to generate a calibration signal, comprising a calibration information indicative of a comparison result, based on comparing the physical characteristic of the surface of the IR emitter with a target value of the physical characteristic of the surface of the IR emitter to obtain the comparison result, and
• wherein, when performing the in-situ calibration, the calibration unit is configured to control the signal generator to adjust the electric pulse based on the calibration information, or the calibration unit is configured to process an output signal of the photoacoustic sensor based on the calibration information to obtain an adjusted output signal of the photoacoustic sensor.

A microelectromechanical system, comprising:

• a photoacoustic sensor comprising an infrared (IR) emitter and a signal generator configured to feed the IR emitter with an electric pulse,
• a calibration unit configured to control the signal generator such that the signal generator feeds the IR emitter with the electric pulse;
• and
• a sensor configured to measure a physical characteristic of a surface of the IR emitter, wherein the physical characteristic of the surface of the IR emitter depends on the electric pulse,
• wherein the calibration unit is configured to generate a calibration signal, comprising a calibration information, based on comparing the physical characteristic of the surface of the IR emitter with a target value of the physical characteristic of the surface of the IR emitter,
• wherein, when performing a calibration of the photoacoustic sensor, the calibration unit is configured to control the signal generator to adjust the electric pulse based on the calibration information, or the calibration unit is configured to process an output signal of the photoacoustic sensor based on the calibration information to obtain an adjusted output signal of the photoacoustic sensor, and
• wherein the IR emitter, the calibration unit, and the sensor are formed in a common semiconductor substrate, wherein the sensor comprises a semiconductor sensing unit formed within the common semiconductor substrate.