Scientific Colloquium
March 27, 2009

"Non-periodic Nanostructure: a New Pathway to Control the Flow of Light "

I will describe a new trend in nano-photonics using non-periodic nanostructures.  By manipulating a network structure at the nanoscale, it is possible to accomplish an unprecedented control over the flow of light.  I will offer two examples. One is the use of a vertically aligned carbon-nanotube array as an absorber - the darkest manmade material [1].  I will present its extraordinary optical scattering properties over a broad wavelength regimes from visible to infrared and Tera-Hertz.  Another is the use of multi-layer nanostructure for achieving a near-perfect antireflection coating [2]. The antireflection coating is effective for nearly all-angle-of-light-incidence and over all solar-wavelength.  Finally, I will discuss our preliminary theoretical understanding of the phenomena.

1.     “A vertically aligned carbon nanotube array: the darkest manmade material”, Nano Letters 8, 446, 2008.
2.    “Realization of a near-perfect antireflection coating for silicon solar utilizations”, Optics Letters 33, 2527, 2008.

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