Coherent anti-Stokes Raman scattering imaging using silicon photomultipliers

Silicon photomultipliers (SiPMs) are an emerging solidstate alternative to photomultiplier tubes (PMTs) for low light detection, with similar gain but lower cost and lower operating voltage. We demonstrate coherent anti-Stokes Raman scattering (CARS) imaging in a side-by-side comparison of an uncooled SiPM with an uncooled multialkali PMT as well as a state-of-the-art cooled GaAsP PMT. We determine the optimum reverse-bias voltage for acquiring the best signal-to-noise ratio (SNR) for CARS imaging of lipids at 2850 cm^-1.We find that despite the higher dark counts, theSNRofCARSimages acquired with the uncooled SiPM biased at an optimum voltage is better than that of the multialkaliPMTand close to that of the cooledGaAsPPMT (~1.5 and~0.8 times, respectively). This is due to the higher gain and lower excess noise factor related to the pulse height variability in the SiPM.