New ‘negative light’ technology hides data transfers in plain sight

Researchers at UNSW Sydney and Monash University have developed a covert data transmission method using 'negative luminescence' — a phenomenon where thermoradiative diodes emit less infrared radiation than the ambient background. This makes signals invisible to thermal cameras and undetectable to outside observers, since the communication blends into natural heat radiation noise. Current lab speeds reach ~100 KB/s, but the team believes graphene-based emitters could push rates to hundreds of GB/s. The technique, called thermoradiative signatureless communication, can also be combined with traditional encryption for layered security, with potential applications in defence and finance.