A sensor device for quantifying luminescent targets comprises a light source, a detector, a modulator, and a processor. The light source is adapted for exciting the luminescent target. The detector is adapted for detecting the luminescence of the luminescent target resulting in a measured signal which comprises a desired signal originating from the luminescent target and a background signal. The modulator is adapted for modulating a physical parameter resulting in a modulation of the desired signal which is different from the modulation of the background signal. The processor is configured to correlate the modulation of the physical parameter with the modulation of the desired signal and/or the modulation of the background signal.