Disorder-Enhanced Transport in Photonic Quasicrystals

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Science  12 May 2011:
DOI: 10.1126/science.1202977


Quasicrystals are aperiodic structures with rotational symmetries forbidden to conventional periodic crystals, examples of which can be found in aluminum alloys, polymers, and even ancient Islamic art. Here, we present direct experimental observation of disorder-enhanced wave transport in quasicrystals, which contrasts directly with the characteristic suppression of transport by disorder. Our experiments are carried out in photonic quasicrystals, where we find that increasing disorder leads to enhanced expansion of the beam propagating through the medium. By further increasing the disorder, we observe that the beam progresses through a regime of diffusive-like transport until it finally transitions to Anderson localization and the suppression of transport. We study this fundamental phenomenon and elucidate its origins by relating it to the basic properties of quasi-crystalline media in the presence of disorder.