Gigacount/Second Photon Detection Module Based on an 8 x 8 Single-Photon Avalanche Diode Array

In this letter, we present a compact photon detection module, based on an 8 x 8 array of single-photon avalanche diodes. The use of a dedicated silicon technology for the fabrication of the sensors allows us to combine large active areas (50-?m diameter), high photon detection efficiency (49% at 550-nm wavelength), and low dark count rate. Because of a fully parallel architecture, the module provides voltage pulses synchronous to each photon detection for a maximum global count rate exceeding 1 Gcps. These properties make the system suitable for operation in two different free-running modes. The first, suitable to acquire faint signals, allows multi-spot acquisitions and can be used to considerably reduce the measurement time in applications, such as single-molecule analysis. With the second, it is possible to use all the pixels in a combined mode, to extend and move the dynamic range of the module to very high count rates and to attain number resolving capabilities.