2×(4×)128 time-gated CMOS single photon avalanche diode line detector with 100 ps resolution for Raman spectroscopy

A 2×(4×)128 multiphase time-gated single photon avalanche diode (SPAD) line detector has been designed and fabricated in a high voltage 0.35 μm CMOS technology for Raman spectroscopy. The time positions of the photons can be measured with the resolution of 100 ps using four time gates over the whole line detector simultaneously. This approach enables to reduce the fluorescence background of the Raman spectrum markedly. Measurements showed that the time gates can be distributed over the whole line detector with the accuracy of ± 35 ps which is adequate for a time-gated pulsed Raman spectroscopy using a laser pulse width of approximately 150 ps.