Time-correlated single-photon counting system based on a monolithic time-to-amplitude converter

Modern time-correlated single-photon counting (TCSPC) systems can achieve very high performance, but advanced applications also demand the implementation of multichannel acquisition chains. To fit the specifics of TCSPC applications we developed a complete single-channel measurement system, composed by three main parts: a single-photon detection module, a TCSPC acquisition board and a power management unit. The system is based on a single-photon avalanche diode (SPAD) and on a fully integrated time-to-amplitude converter (TAC). We designed the module to be very compact, in order to be enclosed in a small case (110 × 50 × 40 mm). The system features high temporal resolution (71 ps), low differential nonlinearity (0.05 LSB), high counting rate (4 MHz) and low power. Moreover a four-channel TAC has already been manufactured and tested; the very low crosstalk between channels, together with low power and low area make the converter suitable for large scale multi-channel acquisition chains, allowing the implementation of architectures for multidimensional TCSPC measurements.