'Data is so ubiquitous nowadays, but we’re not necessarily coming up with new ways to protect it': Researchers develop ‘negative light’ signals that hide transmissions in plain sight
Our exclusive interview with Dr Michael Nielsen from UNSW Sydney
· TechRadarFeatures By Desire Athow Contributions from Wayne Williams published 15 March 2026
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Researchers at the University of UNSW Sydney and Monash University have demonstrated a communication method that hides data transfers inside natural thermal radiation.
The approach (which appears in the journal Light Science and Applications) relies on a phenomenon called negative luminescence, where a device produces radiation that appears darker than the surrounding heat glow in the infrared spectrum.
Every object emits faint infrared radiation from heat. Thermal cameras can detect it, but the human eye can’t. Instead of adding a brighter signal, the system subtly reduces that glow. The change blends into the normal background radiation, making the data transmission difficult to detect.
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New ways to protect data
Dr Michael Nielsen from the UNSW Sydney explains, “Data is so ubiquitous nowadays, but we’re not necessarily coming up with new ways to protect that data. We do have encryption methods, but at the same time we’re always having to create new encryption methodologies when bad actors find new decryption strategies.”
The research group built a device called a thermoradiative diode (pictured above) that can rapidly switch between slightly brighter and darker infrared states, a pattern that encodes information. To outside observers the signal blends into natural infrared noise, so it appears like nothing unusual is happening.
“If someone doesn’t even know the data is being transferred, then it’s really very hard for them to hack into it,” Nielsen said. “If you can send information secretly then it definitely helps to prevent it being acquired by people you don’t want to access it.”
Early laboratory tests transferred data at roughly 100 kilobytes per second and researchers think faster versions are possible as the hardware improves.
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