Scientists Built a 3D Cloak That Makes Objects Almost Invisible to Thermal Cameras

An object doesn’t have to be visible to give away its location. Sometimes, the way it disrupts the flow of heat is enough to reveal that something is hiding there, much to the despair of camouflaged soldiers who have to endure thermal vision drones on the battlefield. Now, engineers have developed a device that can make that thermal signature almost disappear (although sadly it won’t work for infantry).

Researchers at the University of Illinois Urbana-Champaign and the Technical University of Denmark have built a three-dimensional thermal cloak that redirects heat around hidden objects, leaving the surrounding temperature pattern nearly undisturbed. Unlike earlier designs restricted to simpler shapes or only blocking infrared in a single plane, their cloak can accommodate complex geometries and work regardless of the direction of heat flow.

The breakthrough could eventually help protect sensitive electronics, improve heat management in computer chips, and potentially conceal equipment from certain forms of thermal detection.

There’s a catch, however. This isn’t the kind of invisibility cloak that could make a person disappear from a thermal camera. The device redirects heat flowing through solid materials, whereas the human body continuously generates its own heat and emits infrared radiation into the surrounding environment

Making Heat Take the Long Way Around

Heat naturally flows from warmer regions to cooler ones. But if you place an obstacle in the gradient’s path, then the heat flow changes. A poorly conducting object, for instance, forces heat to spread around it, creating distortions that betray its presence.

A thermal cloak must do two things simultaneously: steer heat around the hidden object and restore the original temperature pattern on the other side.

Researchers have pursued this idea for years. In 2014, scientists in Singapore demonstrated a three-dimensional thermal cloak that concealed an air bubble inside metal. More recently, a 2024 study by some of the same researchers produced intricate thermal cloaks, heat rotators and concentrators, primarily using two-dimensional designs.

The challenge was making the effect work around genuinely complex three-dimensional objects, regardless of the direction of heat flow.

“A real thermal cloak should work no matter where the heat comes from,” said Shelly Zhang, an engineering professor at Illinois.

“Our device can hide a complex 3D object in an infinite number of directions while keeping the temperature inside stable and protected.”

To accomplish this, Zhang and her colleagues developed a lattice made from tiny intersecting aluminum bars, surrounded by a rubber-like material called polydimethylsiloxane.

Aluminum conducts heat readily; the rubber conducts it poorly. So by changing the thickness and orientation of the metal bars in three dimensions, the researchers could control precisely where heat traveled.

They used mathematical models to calculate the required properties throughout the cloak, then translated those figures into a continuous structure that could actually be manufactured.

The Strange Experiment That Made an Apple Disappear

The researchers used metal 3D printing to manufacture the aluminum framework, then cast the rubber-like material into the remaining spaces.

To test their design, they created an apple-shaped core concealed inside a pear-shaped shell. They placed the completed specimen between two aluminum plates. One plate was heated to 40 degrees Celsius (104 degrees Fahrenheit), while the other was cooled with iced water.

After an hour, an infrared camera recorded the temperature distributions across the specimen.

Outside the cloak, the temperature bands remained nearly straight and evenly spaced, as though the hidden core were absent. Inside, temperatures varied much less, indicating that relatively little heat crossed the protected region.

The team also fabricated and successfully tested a different, heart-shaped cloak.

But perhaps the most striking demonstration involved human faces. The researchers designed a lattice that could conceal a detailed face-shaped object, complete with glasses, inside another face-shaped structure.

The researchers even 3D-printed intricate, face-shaped cloaks, but only tested their ability to hide heat using computer simulations, not physical experiments. The cloak works by redirecting heat around an object, not by hiding heat produced by the object itself. That means it can’t yet conceal a person or other heat-generating object from a thermal camera.

Still, the work suggests that engineers could eventually route heat around delicate electronic components or maintain more stable temperatures in demanding environments.

“Any field that needs precise control of heat or needs to protect something from being detected thermally could benefit from this work,” Zhang said.

The 3D thermal cloak was described in the journal Nature Communications.