In this thesis, we study light transport through multiple scatteringrandom photonic materials. Light incident on such materials undergoesmany scattering events before exiting the material. The relation betweenthe incident and the transmitted fields is determined by the opticaltransmission matrix of the material. If one knows this matrix, one cansend a pre-designed field to the scattering material to get the desiredtransmitted field. According to theory, light transport throughscattering materials takes place via open transmission eigenchannelswith transmission coefficient close to 1. If one can design an incidentfield that couples only to the open transmission eigenchannels, one canget unity transmission through a scattering material. The theory alsopredicts that the number of open transmission eigenchannels is small.This leads to the transmitted fields to be a superposition of a smallnumber of independent fields and makes them correlated. One can studythese correlations by studying optical transmission matrices ofscattering materials. A large part of this thesis is devoted tomeasuring and analyzing optical transmission matrices of stronglyscattering random photonic materials, in particular random photonic ZnOnanoparticles and GaP nanowire ensembles. As the scattering becomesstronger, the number of open transmission eigenchannels becomes evensmaller, making the transmitted fields even more strongly correlated.When a large enough portion of the transmission matrix is measured,these correlations show up in the singular value histograms of themeasured transmission matrices. We study singular value histograms ofthe measured matrices and observe correlations. We also demonstrateretrieving the scattering strength of the GaP nanowire ensemble from themeasured transmission matrix. Moreover, we study intensity fluctuationsin the speckle transmitted through random photonic ZnO nanoparticlemedia. We observe that the measured speckle intensity histogram is inline with predictions of theory. Finally, we describe an experimentwhere we control light transport through a random photonic TiO2 paintlayer using wavefront shaping with binary amplitude modulation. Weblocked the portion of the field that interferes destructively with therest of the field at a pre-determined target area behind the scatteringsample, creating a bright spot at the target.

Thesis jury: J. F. de Boer (VU Amsterdam), K.-J. Boller, A. Lagendijk, O. L. Muskens (Univ. Southampton, UK), H.-J. Stockmann (Uni Marburg, DE)

D. Akbulut

2013

09/2013

Thesis advisors: A. P. Mosk and W. L. Vos

University of Twente

multiple scattering, speckle statistics, transmission matrix, transportchannels, Wavefront shaping