To quantify the benefits of fluorescence sensing in the NIR region, we simulated optical signals based on a typical scenario (Figure ). The SNR was determined by the fluorescence signal in relation to background noise, which includes back-reflected excitation light, autofluorescence, black body radiation, and the dark noise of the detector. To evaluate the performance of different detector materials, we used representative spectral responsivities of Si and InGaAs PIN photodetectors (Figure ).