Multi-exposure interferometric diffusing wave spectroscopy

Wenjun Zhou, Mingjun Zhao, Oybek Kholiqov, Vivek J. Srinivasan

Research output: Contribution to journalArticlepeer-review


We present multi-exposure interferometric diffusing wave spectroscopy (MiDWS), which measures brain blood flow index (BFI) continuously and non-invasively. MiDWS employs interferometry to detect low light levels, probing the optical field autocorrelation indirectly by varying the sensor exposure time. Here MiDWS is compared with conventional interferometric diffusing wave spectroscopy and speckle contrast optical spectroscopy in phantoms. Notably, the MiDWS approach enables the use of low frame rate, two-dimensional complementary metal–oxide semiconductor cameras in a short exposure time regime, where detector noise greatly exceeds the sample photon count. Finally, we show that MiDWS can monitor the BFI simultaneously at two source-collector separations (1 and 3 cm) on the adult human head on a single camera, enabling the use of superficial signal regression techniques to improve brain specificity.

Original languageEnglish (US)
Pages (from-to)4498-4501
Number of pages4
JournalOptics Letters
Issue number18
StatePublished - Sep 15 2021

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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