A metasurface structure design for performance enhancement of SPAD detectors

This paper discusses several metasurface structures for optimizing the performance of silicon-based SPAD single-photon detectors, enabling them to overcome the material bandgap limitation of silicon and achieve a significant enhancement in absorption efficiency in the wavelength range above 1100nm. The mentioned metasurface structures consist of periodic arrays and utilize Surface Plasmon Resonance (SPR) and three-dimensional cavity effects to induce strong electric field enhancement at the metal-silicon interface through the excitation of Surface Plasmon Polaritons (SPPs). This imparts the detector with a strong light-capturing capability. The performance differences in absorption efficiency among these metasurface structures are elaborated upon, and the feasibility of their integration with SPAD single-photon detectors is discussed.