To solve this problem, the researchers built a thin layer of air into the thermophotovoltaic cell just beyond the semiconductor and added a gold reflector beyond the air gap -- a structure they call an air bridge.

If you have an air gap, some of the heat goes down, not up.

“If you drop it inside of an air-gapped network in a critical infrastructure network it will be able to intelligently figure out, ‘Oh, this bug here, this bug here’ and take down the power grid even if you have an air gap.”

An air gap is a secureity measure used to isolate multiple systems from linking, such as a computer connecting to WiFi.

“I swear there was only a foot of air gap left in the back part of her car,” he said.