Purdue university researchers are developing a new class
of "plasmonic meta materials" as potential building
blocks to built "nanophotonic" devices for various
applications such as focusing and imaging with subwavelength
resolution, invisibility cloaks, and optical black holes
to nanoscale optics, data processing, and quantum information
applications. These materials with refractive index of less
than one and also negative index offer extraordinary response
to electromagnetic, acoustic, and thermal waves that transcends
the properties of natural materials.
The challenges posed in developing these materials are:
too much light is "lost," or absorbed by metals
such as silver and gold contained in the metamaterials,
and the materials need to be more precisely tuned so that
they possess the proper index of refraction.
Now, researchers are proposing a new approach to overcome
these obstacles. Findings will be detailed in an article
appearing Friday (Jan. 21 2011) in the journal Science.
The article was written by Boltasseva and Harry Atwater,
Howard Hughes Professor and a professor of applied physics
and materials science at the California Institute of Technology.
The researchers are working to replace silver and gold
in materials that are created using two options: making
semiconductors more metallic by adding metal impurities
to them; or adding non-metallic elements to metals, in effect
making them less metallic. Examples of these materials include
aluminum oxides and titanium nitride, which looks like gold
and is used to coat the domes of Russian churches.
Researchers have tested some of the new materials, demonstrating
their optical properties and finding that they outperform
silver and gold, in work based at the Birck Nanotechnology
Center in Purdue's Discovery Park.
The possible applications suggested by this material include:
1. 10x more powerful optical microscopes to see objects
as small as DNA
2. New types of light-harvesting systems for more efficient
3. Computers and consumer electronics that use light instead
of electronic signals to process information,
where the nano sized switching transistor lets photons instead
4. And also cloak of invisibility is possible by this material.
These are only a sample of applications, application-exploring
of this material will be a another wave of innovation.
The release also says: Some of the new materials are showing
promise in uses involving near-infrared light, the range
of the spectrum critical for telecommunications and fiberoptics.
Other materials also might work for light in the visible
range of the spectrum. The new materials might be tuned
so that their refractive index is ideal for specific ranges
of the spectrum, allowing their use for particular applications.
These material's behavior looks closer to electric semiconductor
material, where the difference is the semiconductance or
semiresistance is to photon rather than electrons.