Bandwidth Gem

A team led by Sandia National Laboratories scientists has created a tunable plasmonic crystal that could increase the bandwidth of high-speed communication networks and enhance high-speed electronics. The researchers accomplished the effect by making the plasma-containing crystal agile in transmitting terahertz light at varying frequencies. “Usually, electromagnetically induced transparencies in more widely known systems like atomic gases, photonic crystals and metamaterials require tuning a laser’s frequencies to match a physical system,” the scientists explain. “Here, we tune our system to match the radiation source. It’s inverting the problem, in a sense.”

The method could be used to reduce the size of photonic crystals, which are built to allow transmission of specific wavelengths and to develop tunable metamaterials that require micron- or nano-size bumps to tailor interactions between man-made structures and light. The crystal’s electron plasma forms naturally at the interface of semiconductors with different band gaps. As the plasma moves, a crystal forms between the atomically smooth boundaries. Patterned metal electrodes can reconfigure the properties, which alters its light transmission range.