Dual-mode, enhanced dynamic range CMOS optical sensor for biomedical applications

Autor: Shaan Sengupta, Matthew L. Johnston, Hyunkyu Ouh, Soumya Bose
Rok vydání: 2017
Předmět:
Zdroj: BioCAS
DOI: 10.1109/biocas.2017.8325065
Popis: Silicon photodetectors and CMOS image sensors are widely used in biological sensing and medical imaging, where modern CMOS processes provide sufficient sensitivity and noise performance at a lower cost than traditional CCD sensors. At low light intensity, which is increasingly needed for single-molecule and low concentration biosensing, silicon photodetectors are limited by low photocurrent, commensurate with dark current magnitude. In this paper, we present a method to extend the optical dynamic range of a CMOS-integrated photodiode by operating alternately in linear mode and single-photon Geiger-mode using a single p-n junction diode sensor. The architecture was implemented in a commercial 130 nm CMOS process, and measured results are reported across a range of illumination intensities from 30–3000 lux. Results from an optical transmission experiment are provided to demonstrate utility for quantifying chromogenic reactions in lab-on-CMOS immunoassays.
Databáze: OpenAIRE