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Engineering 2D photonic disorder: from incoherent transport to interference
effects.
Matteo [email protected]
The Color of Disorder
Cloud, snow, fog
Random systems are white
Randomness in nature? Really?
Yin et al, PNAS (2012)
Noh et al, Adv. Mat. (2010)
Garcia, Adv. Mat. (2009)
Donev, Science (2004)
Treacy, Science (2012)
Amorphous Silicon
Non-iridescent coloring
Hard sphere
2D engineered-disordered nanophotonic structures
Sapienza L., Science (2010)
Vynck K., Nature Mater. (2012)
Noh H., Phys. Rev. Lett. (2011)
Redding B., Nature Photon. (2013)
Quantum electrodynamics
Random lasers
Light harvesting
Integrated spectrometer
2D correlated disorderThe point patterns generated with the Lubachevsky-Stillinger algorithm.M. Skoge, P.R. E (2006).
Wave transport in these disordered systems
Transport mean free path
Modified scattering cross-section (SCS)
Structure factor
S. Fraden, P.R.L. (1990).
How to calculate it?
Baus-Colot model and the modified SCS
A semi-analytical model to calculate the structure factor valid in n-dimension.We use n=2.
M. Baus and J. L. Colot, P.R. A (1987).
Backward scattering dominate transport
M. Conley et al, arXiv (2013).
Tuning transport: correlation and frequency
Strong modifications at fixed frequency by varying the topology
Pronounced frequency response
Not so white, is it?
Diffusion theory with the Baus-Colot model and numerical calculations
Large deviation at the correlation frequency
Time-resolved 2D FDTD calculation of the electromagnetic field in a unbound systems
Decay rate according to diffusion theory
M. Conley et al, arXiv (2013).
Transition from quasi-extended to localized regime
The mode volume of a localized state can be tuned by controlling the degree of correlation
Breakdown of diffusion theory due to localization effects
Expected a dramatic spectral evolution of the localization length
L=15a
M. Conley et al, arXiv (2013).
Take-home message
Transport properties can be designed semi-analytically by employing the Baus-Colot model;
Large photonic dispersion can be achieved. This leads to a promising control of the extension of localized modes.
Acknowledgements
Kevin VynckGora M. ConleyFilippo Pratesi
Diederik S. Wiersma