Abstract

In my talk I will present recent work on the perfect absorption and transmission of waves through interferometric cancellation of backscattering. In the first case [1], we demonstrate how to construct an anti-reflection structure for a disordered medium. Similar to an anti-reflection coating for conventional eye-glasses, this structure leads to perfect transmission across the scattering system by suppressing back-scattering for any incoming wavefront. In the second case [2], we demonstrate how to achieve perfect absorption of radiation for the case that an absorber is embedded inside a disordered medium. More recently, we have extended this concept to design a device that can turn even a weakly absorbing film into a “coherent perfect absorber” by placing a degenerate cavity around it [3]. This special cavity perfectly couples incoming light fields with arbitrary wavefronts into the absorber – even for the case that light is a dynamically varying speckle pattern. Successful experimental implementations have been carried out with the groups of Matthieu Davy, Ulrich Kuhl and Ori Katz. [1] M. Horodynski, M. Kühmayer, C. Ferise, S. Rotter, and M. Davy, Nature 607, 281 (2022)[2] K. Pichler, M. Kühmayer, J. Böhm, A. Brandstötter, P. Ambichl, U. Kuhl, and S. Rotter, Nature 567, 351 (2019)[3] Y. Slobodkin, G. Weinberg, H. Hörner, K. Pichler, S. Rotter, and O. Katz, Science 377, 995 (2022)