By Daniel Strain

Engineers at CU Boulder have debuted the world’s most efficient optical rectennas—devices that are thinner than the width of a human hair and can capture waste heat and turn it into usable power.

The research was led by Amina Belkadi, who recently earned her PhD from the Department of Electrical, Computer and Energy Engineering (ECEE). And it may be a game-changer for the field of renewable energy. Scientists have long predicted that optical rectennas could sit on top of factory smokestacks or even high-altitude blimps, trapping the energy from heat that would normally go to waste.

To get closer to that reality, the researchers tapped into a ghostly property of the quantum realm called “resonant tunneling” that allows electrons to flow more freely through their device.

“This innovation makes a significant step toward making rectennas more practical,” said coauthor Garret Moddel, professor of ECEE.

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• Scientists debut world’s most efficient 'optical rectennas,' devices that harvest power from heat