Remitted waves are used for sensing and imaging in diverse diffusive media from the Earth's crust to the human brain. Separating the source and detector increases the penetration depth of light, but the signal strength decreases rapidly, leading to a poor signal-to-noise ratio. Here, we show, experimentally and numerically, that wavefront shaping a laser beam incident on a diffusive sample enables an enhancement of remission by an order of magnitude at depths of up to 10 transport mean free paths. We develop a theoretical model which predicts the maximal remission enhancement. Our analysis reveals a significant improvement in the sensitivity of remitted waves to local changes of absorption deep inside diffusive media. This work illustrates the potential of coherent wavefront control for noninvasive diffuse wave imaging applications, such as diffuse optical tomography and functional near-infrared spectroscopy.
N. Bender et al., "Coherent Enhancement of Optical Remission in Diffusive Media," Proceedings of the National Academy of Sciences of the United States of America, vol. 119, no. 41, article no. e2207089119, National Academy of Sciences, Oct 2022.
The definitive version is available at https://doi.org/10.1073/pnas.2207089119
Keywords and Phrases
coherent control; remission; wave diffusion; wavefront shaping
International Standard Serial Number (ISSN)
Article - Journal
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11 Oct 2022