Abstract: The invention relates to a sensor device and a corresponding method for detecting, in particular imaging, thermoacoustic responses of a medium, comprising a detector for detecting acoustic waves, in particular ultrasonic waves, generated in the medium upon absorption of energy from an electromagnetic field and/or from an alternating magnetic field comprising electromagnetic waves or magnetic waves, respectively, of a first frequency. In order to allow for a detection of thermoacoustic responses of the medium, in particular upon absorption of energy from continuous wave (CW) electromagnetic fields and/or from alternating magnetic fields, the detector is designed for detecting acoustic waves of a second frequency which is higher than, in particular twice, the first frequency.