A 256 × 8 SPAD line sensor for time resolved fluorescence and raman sensing

A 256 × 8 single photon avalanche diode (SPAD) time-resolved single photon counting (TCPSC) line sensor enables both fluorescence and Raman spectroscopy in a single device. The 23.78μm pitch, 46.8% fill-factor SPAD array is implemented in a 0.13μm CMOS image sensor process. Integrating time to digital converters (TDCs) implement on-chip mono-exponential fluorescence lifetime pre-calculation allowing timing of 65k photons/pixel at 500s-1 line rate at 40ps resolution using centre-of-mass method (CMM). TCSPC histograms may also be generated with 320ps bin resolution for multi-exponential analysis.