Sensor device, a photo-acoustic imaging device and a method for detecting a measurand

A sensor device comprising:

• a plurality of sensors, wherein each sensor comprises an optical resonance element, wherein an optical characteristic of the optical resonance element is configured to be affected by a measurand to be measured by the sensor and wherein each sensor in the plurality of sensors has a mutually unique optical resonance frequency;
• the plurality of sensors being configured to receive at least one of a first and a second sensor interrogation signals, wherein the first sensor interrogation signal comprises a first optical frequency comb of first frequencies defining a plurality of first signal components being separated by a first repetition frequency, wherein the second sensor interrogation signal comprises a second optical frequency comb of second frequencies defining a plurality of second signal components being separated by a second repetition frequency different from the first repetition frequency, wherein each of the plurality of first signal components is associated with a respective one of the plurality of second signal components to form a plurality of signal component pairs, wherein a difference in frequency between the associated first signal component and second signal component is different for different signal component pairs;
• wherein an optical resonance of the optical resonance element of each sensor is associated with one, mutually unique, signal component pair of the plurality of signal component pairs such that each sensor is configured to modulate the at least one of the first and second sensor interrogation signal by the measurand to modulate an optical intensity and/or phase of at least one of the associated first signal component and second signal component of the mutually unique signal component pair;
• and
• a detector, being configured to receive the first sensor interrogation signal and the second sensor interrogation signal, at least one of which being modulated by the plurality of sensors being affected by the measurand, wherein the detector is configured to detect a plurality of beat frequencies corresponding to mutually unique differences in frequency between the associated first signal component and second signal component for different signal component pairs for detecting a plurality of measurements by the plurality of sensors.