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Engineers at the University of California San Diego have developed a material that could reduce signal losses in photonic devices. The advance has the potential to boost the efficiency of various light-based technologies including fiber optic communication systems, lasers and photovoltaics addressing one of the biggest challenges in the field of photonics: minimizing loss of optical (light-based) signals in devices known as plasmonic metamaterials.

Plasmonic metamaterials are materials engineered at the nanoscale to control light in unusual ways. They can be used to develop exotic devices ranging from invisibility cloaks to quantum computers. But a problem with metamaterials is that they typically contain metals that absorb energy from light and convert it into heat. As a result, part of the optical signal gets wasted, lowering the efficiency.

In a recent study published in Nature Communications, a team of photonics researchers led by electrical engineering professor Shaya Fainman at the UC San Diego Jacobs School of Engineering, have demonstrated a way to make up for the losses incurred by metals in metamaterials which cause loss of signals and lowered efficiency by incorporating something that emits light - a semiconductor.

In their experiments, the researchers shined light from an infrared laser onto the meta-material. This showed that depending on which way the light is polarized - which plane or direction (up and down, side to side) all the light waves are set to vibrate - the meta-material either reflects or emits light. Researchers created the new meta-material by first growing a crystal of the semiconductor material, called Indium Gallium Arsenide Phosphide, on a substrate. They then used high-energy ions from plasma to etch narrow trenches into the semiconductor, creating 40-nanometer-wide rows of semiconductor spaced 40 nanometers apart. Finally, they filled the trenches with silver to create a pattern of alternating nano-sized stripes of semiconductor and silver.

As a next step, the team plans to investigate how much this meta-material and other versions of it could improve photonic applications that currently suffer from signal losses. To read the published research paper, click here.