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bioRxiv · 10.1101/2020.07.08.193433

Fast and sensitive diffuse correlation spectroscopy with highly parallelized single photon detection

Wenhui Liu·Ruobing Qian·Shiqi Xu·Pavan Chandra Konda·Mark Harfouche·Dawid Borycki·Joakim Jonsson·Edouard Berrocal·Colin Cooke·Allie Sinclair·Haoqian Wang·Qionghai Dai·Roarke W. Horstmeyer
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Abstract

Diffuse correlation spectroscopy (DCS) is a well-established method that measures rapid changes in scattered coherent light to identify blood flow and functional dynamics within tissue. While its sensitivity to minute scatterer displacements leads to a number of unique advantages, conventional DCS systems become photon-limited when attempting to probe deep into tissue, which leads to long measurement windows ([~]1 sec). Here, we present a high-sensitivity DCS system with 1024 parallel detection channels integrated within a single-photon avalanche diode (SPAD) array, and demonstrate the ability to detect mm-scale perturbations up to 1 cm deep within a tissue-like phantom at up to 33 Hz sampling rate. We also show that this highly parallelized strategy can measure the human pulse at high fidelity and detect behaviorally-induced physiological variations from above the human prefrontal cortex. By greatly improving detection sensitivity and speed, highly parallelized DCS opens up new experiments for high-speed biological signal measurement.

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Wenhui Liu, Ruobing Qian, Shiqi Xu, Pavan Chandra Konda, Mark Harfouche, Dawid Borycki, Joakim Jonsson, Edouard Berrocal, Colin Cooke, Allie Sinclair, Haoqian Wang, Qionghai Dai, Roarke W. Horstmeyer. 2020-07-10. Fast and sensitive diffuse correlation spectroscopy with highly parallelized single photon detection. https://doi.org/10.1101/2020.07.08.193433

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