Curtis Jin, Raj Rao Nadakuditi, Eric Michielssen, Stephen Rand
Scattering hinders the passage of light through random media and consequently limits the usefulness of optical techniques for sensing and imaging. Thus, methods for increasing the transmission of light through such random media are of interest. Against this backdrop, Dorokhov, Pendry and others theoretically predicted the existence of a few highly transmitting eigen-wavefronts with transmission coefficients close to one in strongly backscattering random media. The breakthrough experiments of Vellekoop and Mosk confirmed the existence of these highly transmitting eigen-wavefronts and demonstrated that they could be discovered by using information from the far side of the scattering medium. Here, we numerically analyze this phenomenon in 2-D with fully spectrally accurate simulators and provide rigorous numerical evidence confirming the existence of these highly transmitting eigen-wavefronts in random media composed of hundreds of thousands of non-absorbing scatterers. We then develop physically realizable algorithms for increasing the transmission through random media using backscatter analysis. We show via numerical simulations that the algorithms converge rapidly, yielding a near-optimum wavefront in just a few iterations. We also develop an algorithm that combines the knowledge of these highly transmitting eigen-wavefronts obtained from backscatter analysis with intensity measurements at a point to produce a focus using significantly fewer measurements.
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http://arxiv.org/abs/1303.3617
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