An on-chip 72×60 angle-sensitive single photon image sensor array for lens-less time-resolved 3-D fluorescence lifetime imaging

We present a 72×60, angle-sensitive single photon avalanche diode (A-SPAD) array, able to perform lens-less 3-D fluorescent lifetime imaging. A-SPAD pixels are comprised of (1) a SPAD to resolve precise timing information, reject high-powered UV stimulus, and map the lifetimes of different fluorescent sources and (2) integrated diffraction gratings over the SPAD to extract the incident angle of light, enabling 3-D localization at a micrometer scale. The chip integrates pixel-level counters and shared timing circuitry, and is implemented in unmodified 180nm CMOS.