Scientists have developed a technology to invisibly transmit information disguised as thermal background radiation. Using a phenomenon called “negative light”, they transmitted 100 kilobits of data per second in a way that was completely undetectable to outside observers.
Most methods of hiding data in transit involve hiding it among other data or encrypting it in a way that makes it impossible to read without a cipher or other decryption methods. The new technique, however, makes the data almost impossible to intercept because there is no indication that it is being sent at all. It can also be encrypted using traditional means to further harden security, the team wrote in a paper published March 5 in the journal Light: Science and Applications.
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The negative luminescence the team used could make the glow dimmer, rather than brighter. In one statement, Michael Nielsenprofessor of engineering at the University of New South Wales Sydney and lead author of the study, likened it to a flashlight that could “project darkness” compared to background light, instead of just turning off.
Using devices called thermo-emitting diodes, the team created patterns of brighter or darker-than-usual states that blended into typical infrared background noise but could be read as data by specialized receivers.
The thermo-radiating diodes were born as part of another project, where the team proved that it was possible to generate solar energy even after the sun had set. This “night solar” technology captured infrared radiation that the Earth had absorbed during the day and released it at night as it cooled. The team then used thermo-emitting diodes to generate a small amount of electricity.
While the native transfer rate of 100 kbps is quite modest, Nielsen said higher speeds are achievable. The main obstacle was the availability of some of the sophisticated electronics the team needed. In principle, there is nothing to prevent this method from transmitting tens of megabits per second with existing devices, with better devices and detector designs pushing the speed to gigabits per second, the team said.
Indeed, a commercial product delivering megabit-per-second data rates may be possible in just a few years, Ned Ekins-Daukesa professor of photovoltaic and renewable energy engineering at UNSW and co-leader of the research, said in the statement.
By using graphene — a single-atom-thick sheet of carbon atoms arranged in a honeycomb pattern — instead of the current semiconductor material in the diodes, “we can potentially achieve data transfer rates in the gigabit-per-second range, if not hundreds of gigabits,” Ekins-Daukes said.
Improved data security will have major applications in a variety of industries, including healthcare, defense, finance and manufacturing. Nielsen believes that virtually any communication that can benefit from security beyond standard encryption can benefit from the team’s breakthrough.
“The real advantage of this technique is that the actual signal or act of communication is hidden if an outside observer does not have the same technology required to intercept the communication,” Nielsen told LiveScience in an email.
Nielsen, MP, Maier, SA, Fuhrer, MS et al. Balances positive and negative luminescence for thermal radiation signatureless communication. Light Sci Appl 15, 148 (2026). https://doi.org/10.1038/s41377-025-02119-y
