CMOS Sensor for Fluorescence Lifetime Imaging

Fluorescence lifetime (τ) is defined as an average time of the excited fluorescent photons staying in the excited state prior to returning to the ground state. Because lifetime of the fluorescent probe is dependent on ion concentration, ion concentration can be quantified through the lifetime. Due to advantage in feasible quantification, fluorescence lifetime measurement has become more effective than fluorescence intensity measurement.
We propose a compact and low-cost FLIM (Fluorescence Lifetime Imaging Microscopy) system based on a time-resolved (TR) CMOS image sensor. By using a pixel structure which is capable of high speed charge transfer and draining, fluorescence lifetime can be successfully measured in real time at 200ps time resolution.

References

1. H. J. Yoon, S. Kawahito,"A CMOS Image Sensor for Fluorescence Lifetime Imaging", IEEE SENSORS, pp. 400-403, 2006
2. H. J. Yoon, S. Ito and S. Kawahito, "A CMOS Image Sensor with In-Pixel Two-Stage Transfer for Fluorescence Lifetime Imaging", IEEE Transactions on Electron Devices, Vol. 56, No. 2, pp. 214-221, Feb. 2009.
3. Z. Li, K. Yasutomi, T. Takasawa, S. Itoh and S. Kawahito, "A CMOS image sensor with draining only modulation pixels for fluorescence lifetime imaging", in Proc. SPIE-IS&T Electronic Imaging, vol. 7875, San Fransisco, CA, Jan. 2011, pp. 78750D-1 -- 78750D-8.
4. S. Kawahito, Z. Li, and K. Yasutomi, "A CMOS image sensor with draining only modulation pixels for sub-nanosecond time-resolved imaging", in Proc. International Image Sensor Workshop, Hokkaido, Japan, Jun. 2011, pp. 185-188.
5. Z. Li, S. Kawahito, K. Yasutomi, K. Kagawa, J. Ukon, M. Hashimoto, H. Niioka, "A time-resolved CMOS image sensor with draining-only modulation pixels for fluorescence lifetime imaging", IEEE Transactions on Electron Devices, vol. 59, no. 10, pp. 2715-2722, Oct. 2012.