Single photon counting module based on large area APD and novel logic circuit for quench and reset pulse generation

We present the design, implementation, and characterization of a single-photon counting module (SPCM) based on large-area avalanche photodiode (APD) and new logic circuit based on TTL integrated circuits (ICs) for generating precise quench and reset delays. Low dark count rate, high linearity of ~2 MHz, maximum dynamic range of ~12 MHz, and minimum dead time of 35 ns have been achieved with 0.2 mm² peltier-cooled single photon avalanche diode (SPAD) [model C30902S-DTC, Perkin Elmer Optoelectronics (PKI)]. The developed module was fiberized and tested for the detection of fluorescently labeled DNA sequences. Detection sensitivity at the level of single fluorescent molecule has been demonstrated.