Harvard Physicists Propose a Device to Capture Energy from the Earch’s Infrared Emissions to Outer Space

Cambridge, Mass. ā March 3, 2014 ā When the sun sets on a remote desert outpost and solar panels shut down, what energy source will provide power through the night? A battery, perhaps, or an old diesel generator? Perhaps something strange and new.
Heated by the sun, our planet is warm compared to the frigid vacuum beyond. Thanks to recent technological advances, the researchers say, that heat imbalance could soon be transformed into direct-current (DC) power, taking advantage of a vast and untapped energy source.
āItās not at all obvious, at first, how you would generate DC power by emitting infrared light in free space toward the cold,ā says principal investigator Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at Harvard SEAS. āTo generate power by emitting, not by absorbing light, thatās weird. It makes sense physically once you think about it, but itās highly counterintuitive. Weāre talking about the use of physics at the nanoscale for a completely new application.ā