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Fully Integrated Time-Gated 3D Fluorescence Imager for Deep Neural Imaging

Choi, Jaebin and Taal, Adriaan J. and Meng, William L. and Pollmann, Eric H. and Stanton, John W. and Lee, Changhuk and Moazeni, Sajjad and Moreaux, Laurent C. and Roukes, Michael L. and Shepard, Kenneth L. (2020) Fully Integrated Time-Gated 3D Fluorescence Imager for Deep Neural Imaging. IEEE Transactions on Biomedical Circuits and Systems, 14 (4). pp. 636-645. ISSN 1932-4545. doi:10.1109/tbcas.2020.3008513.

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This paper presents a device for time-gated fluorescence imaging in the deep brain, consisting of two on-chip laser diodes and 512 single-photon avalanche diodes (SPADs). The edge-emitting laser diodes deliver fluorescence excitation above the SPAD array, parallel to the imager. In the time domain, laser diode illumination is pulsed and the SPAD is time-gated, allowing a fluorescence excitation rejection up to O.D. 3 at 1 ns of time-gate delay. Each SPAD pixel is masked with Talbot gratings to enable the mapping of 2D array photon counts into a 3D image. The 3D image achieves a resolution of 40, 35, and 73 μm in the x, y, and z directions, respectively, in a noiseless environment, with a maximum frame rate of 50 kilo-frames-per-second. We present measurement results of the spatial and temporal profiles of the dual-pulsed laser diode illumination and of the photon detection characteristics of the SPAD array. Finally, we show the imager's ability to resolve a glass micropipette filled with red fluorescent microspheres. The system's 420 μm-wide cross section allows it to be inserted at arbitrary depths of the brain while achieving a field of view four times larger than fiber endoscopes of equal diameter.

Item Type:Article
Related URLs:
URLURL TypeDescription
Choi, Jaebin0000-0002-8348-7701
Taal, Adriaan J.0000-0002-1649-2826
Moreaux, Laurent C.0000-0003-1276-5062
Roukes, Michael L.0000-0002-2916-6026
Shepard, Kenneth L.0000-0003-0665-6775
Additional Information:© 2020 IEEE. Manuscript received March 10, 2020; revised May 13, 2020; accepted June 16, 2020. Date of publication July 10, 2020; date of current version August 17, 2020. This work was supported in part by the National Institutes of Health under Grant U01NS090596 and in part by the Defense Advanced Research Projects Agency (DARPA) under Contract N66001–17-C-4012. The authors would also like to thank TSMC for SPAD fabrication support.
Funding AgencyGrant Number
Defense Advanced Research Projects Agency (DARPA)N66001-17-C-4012
Subject Keywords:Single photon avalanche diode, time-gated fluorescence imaging, neural imaging, computational imaging
Issue or Number:4
Record Number:CaltechAUTHORS:20200716-151318688
Persistent URL:
Official Citation:J. Choi et al., "Fully Integrated Time-Gated 3D Fluorescence Imager for Deep Neural Imaging," in IEEE Transactions on Biomedical Circuits and Systems, vol. 14, no. 4, pp. 636-645, Aug. 2020, doi: 10.1109/TBCAS.2020.3008513
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104414
Deposited By: Tony Diaz
Deposited On:16 Jul 2020 23:56
Last Modified:16 Nov 2021 18:31

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