A fiber-optic-based multichannel time-correlated single-photon-counting device with subnanosecond time resolution

A fiber-optic-based multichannel time-correlated single-photon-counting dev ice with subnanosecond time resolution was developed. A passively mode-lock ed Ti: sapphire laser provided the excitation source for 12 separate time-c orrelated single-photon counting channels in which three single-photon aval anche diode detectors were used to analyze the fluorescence from the channe ls. Single-mode optical fibers provided the conduit for the excitation ligh t as well as the fluorescence emission. We determined that the excitation p ulses undergo a temporal spread of 50 fs, a spectral spread of 0.2 nm, and remained nearly transform limited. The average instrument response function of each channel was determined to be 181 ps (full width at half maximum). The fluorescence lifetime of a representative near-infrared dye, aluminum t etrasulfonated naphthalocyanine, was determined to be 3.08 ns using this fi ber-optic-based multichannel time-correlated single-photon-counting device. (C) 1999 American Institute of Physics. [S0034-6748(99)01401-X].