Researchers Create Tunable Plasmonic Crystal

Researchers Create Tunable Plasmonic Crystal

1 November 2013

Researchers in New Mexico have created a plasmonic crystal that can be tuned to match the voltage applied to its plasma, reports.

The plasmonic crystal can transmit terahertz light at fluctuating frequencies, a property which can pave the way for an increase in the bandwith of high-speed communication networks and bolster high-speed electronics as a whole.

Plasmonic crystals are known for their ability to direct light like photonic crystals but, thanks to their subwavelength size, they could be used to reduce the size of photonic crystals and underpin the development of tunable metamaterials. Unlike plasmonic crystals, photonic crystals are artificially designed to enable light transmission of specific wavelengths.

The plasmonic crystal was created by a team led by Sandia National Laboratory and work on the project is detailed in Nature Photonics magazine in a paper titled "Induced transparency by coupling of Tamm and defect states in tunable terahertz plasmonic crystals."

The electronic plasma contained in the crystal, which forms naturally at the interface of semiconductors with different band gaps, slips between their atomically even boundaries which form a crystal. Thanks to the crystal's patterned metal electrodes, its properties can be rearranged, changing its light transmission range. Light can also be transmitted even where the crystal is normally obscure due to the defects deliberately incorporated into the electron fluid.

The experiment is "more than a curiosity" since the plasma resonances are increasingly tunable, commented Sandia researcher Greg Dyer, the project's co-primary investigator. In general, electromagnetically induced transparencies in more popular devices such as photonic crystals and metamaterials require tuning a laser's frequencies to match a physical system. With plasmonic crystals, the team tunes their system to tone with the source of radiation, he said.