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Detection of circular polarization in light scattered from photosynthetic microbes



William Sparks, James H. Hough, Thomas Germer, Feng Chen, Shiladitya DasSarma, Priya DasSarma, Frank Robb, Nadine Manset, Ludmilla Kolokolova, Neill Reid, F. D. Macchetto, William Martin


The identification of a universal biosignature that could be sensed remotely is critical to the prospects for success in the search for life elsewhere in the universe. A candidate universal biosignature is homochirality, which is likely to be a generic property of all biochemical life. Because of the optical activity of chiral molecules, it has been hypothesized that this unique characteristic may provide a suitable remote sensing probe using circular polarization spectroscopy. Here, we report the detection of circular polarization in light scattered by photosynthetic microbes. We show that the circular polarization appears to arise from circular dichroism of the strong electronic transitions of photosynthetic absorption bands. We conclude that circular polarization spectroscopy could provide a powerful remote sensing technique for generic life searches.
Proceedings of the National Academy of Sciences


astrobiology, chirality, circular dichroism, diffuse scattering


Sparks, W. , Hough, J. , Germer, T. , Chen, F. , DasSarma, S. , DasSarma, P. , Robb, F. , Manset, N. , Kolokolova, L. , Reid, N. , Macchetto, F. and Martin, W. (2009), Detection of circular polarization in light scattered from photosynthetic microbes, Proceedings of the National Academy of Sciences, [online], (Accessed June 17, 2024)


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Created May 11, 2009, Updated October 12, 2021