Plasmonic crystal alters to match light-frequency source

October 29, 2013, Sandia National Laboratories
Sandia National Laboratories researcher Greg Dyer aligns a plasma-containing crystal that is tunable by varying the voltage. The technology potentially could increase the bandwidth of high-speed communications networks. Credit: Randy Montoya, Sandia National Laboratories

Gems are known for the beauty of the light that passes through them. But it is the fixed atomic arrangements of these crystals that determine the light frequencies permitted passage.

Now a Sandia-led team has created a plasmonic, or -containing, crystal that is tunable. The effect is achieved by adjusting a voltage applied to the plasma. Because the crystal then is agile in transmitting terahertz light at varying frequencies, it could increase the bandwidth of high-speed communication networks and generally enhance high-speed electronics.

"Our experiment is more than a curiosity precisely because our plasma resonances are widely tunable," says Sandia researcher Greg Dyer, co-primary investigator of a recently published online paper in Nature Photonics, expected in print in November. "Usually, electromagnetically induced transparencies in more widely known systems like atomic gases, photonic and metamaterials require tuning a laser's frequencies to match a physical system. Here, we tune our system to match the radiation source. It's inverting the problem, in a sense."

Photonic crystals are artificially built to allow transmission of specific wavelengths. Metamaterials require micron- or nano-sized bumps to tailor interactions between manmade structures and light. The plasmonic crystal, with its ability to direct light like a , along with its sub-wavelength, metamaterial-like size, in effect hybridizes the two concepts. Its methods could be used to shrink the size of photonic crystals and to develop tunable .

The crystal's electron plasma forms naturally at the interface of semiconductors with different band gaps. It sloshes between their atomically smooth boundaries that, properly aligned, form a crystal. Patterned metal electrodes allow its properties to be reconfigured, altering its light transmission range. In addition, defects intentionally mixed into the electron fluid allow light to be transmitted where the crystal is normally opaque.

However, this crystal won't be coveted for the beauty of its . First, the crystal transmits in the terahertz spectrum, a frequency range invisible to the human eye. And scientists must tweak the crystal's two-dimensional electron gas to electronically vary its output frequencies, something casual crystal buyers probably won't be able to do.

Explore further: Butterfly inspires new nanotechnology

More information: The paper is titled "Induced transparency by coupling of Tamm and defect states in tunable terahertz plasmonic crystals."

Related Stories

Butterfly inspires new nanotechnology

September 2, 2013

By mimicking microscopic structures in the wings of a butterfly, an international research team has developed a device smaller than the width of a human hair that could make optical communication faster and more secure.

Organic crystals put laser focus on magnetism

July 27, 2012

(Phys.org) -- In the first successful experiment of its type at SLAC's Linac Coherent Light Source, scientists used terahertz frequencies of light to change the magnetic state of a sample and then measured those changes with ...

Researchers glimpse the inside of a photonic crystal

October 2, 2012

(Phys.org)—While today's smart phones, tablets, and other small electronic devices rely on electrical data connections, in the future they may use optical connections in order to become even faster and smaller. Photonic ...

Recommended for you

Sculpting stable structures in pure liquids

February 21, 2019

Oscillating flow and light pulses can be used to create reconfigurable architecture in liquid crystals. Materials scientists can carefully engineer concerted microfluidic flows and localized optothermal fields to achieve ...

How to freeze heat conduction

February 21, 2019

Physicists have discovered a new effect, which makes it possible to create excellent thermal insulators which conduct electricity. Such materials can be used to convert waste heat into electrical energy.

Water is more homogeneous than expected

February 21, 2019

In order to explain the known anomalies in water, some researchers assume that water consists of a mixture of two phases, even under ambient conditions. However, new X-ray spectroscopic analyses at BESSY II, ESRF and Swiss ...

Correlated nucleons may solve 35-year-old mystery

February 20, 2019

A careful re-analysis of data taken at the Department of Energy's Thomas Jefferson National Accelerator Facility has revealed a possible link between correlated protons and neutrons in the nucleus and a 35-year-old mystery. ...

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

bearly
not rated yet Oct 29, 2013
My imagination wonders if this will someday apply to a "dilithium crystal" faster than light drive.
KBK
1 / 5 (2) Oct 30, 2013
So the crystal becomes akin to the source?

Good.

Now phase lock that output back to source.
antialias_physorg
not rated yet Oct 30, 2013
Now phase lock that output back to source.

We're talking frequency here - not phase.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.