A Single-Photon Avalanche Diode Array for Fluorescence Lifetime Imaging Microsco

Abstract

o Charbon , Member , IEEE, and Kenneth L. Shepard , Fellow, IEEE Abstract—We describe the design, characterization, and demon- stration of a fully integrated single-photon avalanche diode (SPAD) imager for use in time-resolved fluorescence imaging. The imager consists of a 64-by-64 array of active SPAD pixels and an on-chip time-to-digital converter (TDC) based on a delay-locked loop (DLL) and calibrated interpolators. The imager can perform both standard time-correlated single-photon counting (T