Engineering 2D photonic disorder: from incoherent transport to interference

effects.

Matteo Burresiburresi@lens.unifi.it

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