40 × 40 Metalens Array for Improved Silicon Photomultiplier Performance
Soh Uenoyama, R. Ota
Abstract
The photon detection efficiency (PDE) and timing performance of silicon photomultipliers (SiPMs) need to be improved for various applications, including time-of-flight positron emission tomography, light detection and ranging, and high-energy physics experiments. However, the irradiation of some incident photons to the low-photosensitivity areas of the SiPM negatively affects its PDE and timing performance. In this study, we developed a 40 × 40 metalens array to focus incident photons on the photosensitive area of the SiPM, thereby improving the PDE and timing performance. As a proof of concept, we experimentally investigated the effectiveness of this method. After characterizing the fabricated metalens, we found that the focused beam size is approximately 1 μm (full width at half-maximum) at the optimal focal plane. Furthermore, we demonstrated the effectiveness of the metalens in significantly improving the PDE (within a 5.8 σ confidence level) and timing performance (within a 3.0 σ confidence level). The results demonstrate the potential for using metalenses for versatile applications of SiPMs.