Photoacoustic gas sensors and method of operating a photoacoustic gas sensor

A method of operating a photoacoustic gas sensor comprising a microphone system arranged inside a hermetically sealed housing, wherein the housing is filled with a reference gas, the method comprising:

• generating a first microphone signal using the microphone system,
• wherein the first microphone signal comprises a first signal component, related to a photoacoustic excitation of the reference gas, and a third signal component related to mechanical vibrations of the photoacoustic gas sensor;
• generating a second microphone signal using the microphone system,
• wherein the second microphone signal comprises a second signal component, related to the photoacoustic excitation, and a fourth signal component related to the mechanical vibrations of the photoacoustic gas sensor;
• and
• generating an output signal based on the first microphone signal and the second microphone signal by destructively superimposing the third signal component and the fourth signal component.

A photoacoustic gas sensor, comprising:

• a hermetically sealed housing filled with a reference gas;
• a first membrane arranged inside the housing;
• and
• a second membrane arranged inside the housing,
• wherein the first membrane comprises a first main surface configured to receive sound waves from the reference gas and a second main surface opposite to the first main surface,
• wherein the second membrane comprises a third main surface configured to receive the sound waves and a fourth main surface opposite to the third main surface,
• wherein the second main surface and the fourth main surface are not subject to the reference gas, and
• wherein the first membrane and the second membrane are oriented such that a first direction pointing from the first main surface to the second main surface is opposite to a second direction pointing from the third main surface to the fourth main surface.