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Metafluids and Parity-Time symmetric metamaterials: New optical material phases and phenomena

April 13, 2016 - 11:00am
Hadiseh Alaeian
IAP-Universität Bonn

Textbook conceptions of light-matter interactions have been challenged by two recent material
advances - the development of metamaterials and the introduction of parity-time (PT)-symmetric
media. Metamaterials allow considerable control over the electric and magnetic fields of light, so
that the permittivity, permeability, and refractive index can be tuned throughout positive, negative,
and near-zero values. Metamaterials have enabled negative refraction, optical lensing below the
diffraction limit of light and invisibility cloaking. Complementarily, PT-symmetric media allow
control over electromagnetic field distributions in systems with balanced amounts of gain and loss,
so that light propagation can be asymmetric and directional. They have enabled lossless Talbot
revivals, unidirectional invisibility, and, combined with non-linear media, optical isolators.

In this talk, I will elaborate on our efforts to make new types of optical and asymmetric
metamaterials, including liquid metamaterials and parity-time symmetric metamaterials. First, I
will describe our work on the design and demonstration of the first fluidic metamaterial. Rather
than relying on top-down fabrication techniques, we utilize protein directed assembly to synthesize
the constituent meta-molecules. Both individual meta-molecules and the bulk metamaterial
solution show a strong isotropic magnetic polarizability at optical frequencies. Our calculations
also indicate that these meta-molecules could enable negative refractive index liquids.
Then, I will introduce the new concept of Parity-Time symmetric nanophotonic materials. We
show how planar and coaxial metallo-dielectric structures with balanced inclusion of gain and loss
can be used for a variety of applications, including i) directional nanophotonic waveguides and
modulators; ii) directional metamaterials that have different refractive indices when viewed from
different sides; and iii) flat Veselago lenses which can overcome the Rayleigh diffraction limit of
conventional optical microscopy. Further, I will show how these meta-materials can be used to
control the emission of the electric, magnetic and chiral emitters and suggest a non-chiral platform
for enantio-specific identification and selection.

3100A Computer and Space Sciences
College Park, MD 20742