Performance of a 6 × 6 mm² SiPM Module for Time-Domain Diffuse Optics

In this work we present a detector module based on large-area silicon photomultiplier, whose design has been optimized for time-domain diffuse optics measurements. In this application, to the best of our knowledge, it represents the largest area detector ever demonstrated, with expected breakthrough performance in terms of scattered light harvesting efficiency. It has been characterized using widely adopted protocols for performance assessment of instruments. We demonstrate the superior light harvesting capability and improved depth sensitivity, which can reach 4 cm. Moreover, the retrieval of optical properties has been demonstrated to be linear and with sufficient accuracy in the range corresponding to the human tissues. As a first step toward clinical application, we first performed in-vivo measurement at very large source-detector distances to show the suitability of the realized detector to tackle new challenges like lung or heart optical monitoring as well as imaging of deep cerebral function.