A Nano-Filter-Integrated CMOS Image Sensor for Fluorescent Biomedical Imaging

This paper presents a fluorescent image sensor with the integrated plasmonic nano-filter using metal layers in CMOS. The readout circuit is fully integrated with a high-gain pixel-level capacitive trans-impedance amplifier (CTIA), column-level amplifier, and correlated double sampling (CDS). The nano-filter achieved 51-dB simulated rejection ratio for 467-nm excitation light and 820-nm emission light. Considering low photodiode quantum efficiency and interference, a 24.2-dB system rejection ratio was achieved in measurement. In addition, liquid samples with/without PbS quantum dots (QDs) can be identified with 22-dB transmittance difference.