Information and Light in Complex Media

Institute of Microengineering - Distinguished Lecture

Due to the covid-19 related restrictions currently in place, the lecture will be held remotely by zoom only.

Zoom Live Stream: https://epfl.zoom.us/j/119888136

Abstract: Random scattering of light, which takes place in paper, paint and biological tissue is an obstacle to imaging and focusing of light and thus hampers applications ranging from laser ablation to precision measurements. At the same time scattering is a phenomenon of basic physical interest as it allows the study of fascinating interference effects such as open transport channels [1,2], which enable lossless transport of waves through strongly scattering materials. The frequency bandwidth of these channels [3] is critical to their usefulness as it determines their ability to carry pulses and their information-carrying capacity. After a broad overview of the field, we present new measurements of the frequency bandwidth and intensity fluctuations in these channels. Moreover, we show that  optimizing the incident light wave is essential to  extract precise information about the position of any scatterer. The information we retrieve turns out to be limited by our knowledge of the position of the other scatterers and the local density of states [5].

Bio: Allard Mosk (1970) started his physics career in ultracold atomic gases with work in Amsterdam (Ph.D. 1994), Heidelberg, and Paris, performing the first observation of a Feshbach resonance in Li, and of photoassociation of H. In 2003 he joined the Complex Photonic Systems group at the University of Twente. where he pioneered wavefront shaping methods to focus and image through strongly scattering media. Since 2015 he holds a chair at Utrecht University, The Netherlands, where he studies statistical properties of light in complex scattering media with a view on imaging and optical precision measurements.

References:

1. A. P. Mosk, A. Lagendijk, G. Lerosey, and M. Fink, Controlling waves in space and time for imaging and focusing in complex media, Nat. Photon., 6, 283 (2012).
2. I.M. Vellekoop and A.P. Mosk, Universal optimal transmission of light through disordered materials, Phys. Rev. Lett. 101, 120601 (2008).
3. Jeroen Bosch, Sebastianus A. Goorden, and Allard P. Mosk, Frequency width of open channels in multiple scattering media, Opt. Expr. 24, 26472-26478 (2016)
4. X. Xu, X. Xie, A. Thendiyammal, H. Zhuang, J. Xie, Y. Liu, J. Zhou, and A. P. Mosk, Imaging of objects through a thin scattering layer using a spectrally and spatially separated reference, Opt. Express 26 (12), 15073–15083 (2018).
5. D. F. Bouchet, R. Carminati, and A. P. Mosk, Influence of the local density of states on the localization precision of single particles in scattering environments, arXiv. org 1909.02501 (2019).