Researchers at Southeast University in Nanjing, China have created a device that traps and absorbs electromagnetic waves coming from all directions, spiraling them inwards without any reflections, essentially creating an electromagnetic black hole. Qiang Cheng and Tie Jun Cui’s “omnidirectional electromagnetic absorber” draws in microwaves coming from any direction by spiraling radiation inwards, and converting its energy into heat. They plan on developing a device that can absorb visible light next.
Working in the university’s State Key Laboratory of Millimeter Waves, Cheng and Cui built their device from 60 strips of circuit board, arranged in concentric layers and coated in metamaterials. The spiraling effect was created by using non-microwave-resonant metamaterials on the outer layer, while using resonant ones in the inner core. Obviously, there was a little more to it than that, but the end result was a gizmo that absorbed 99 percent of incoming microwave radiation.
Besides Lex Luthor and company, who might be interested in such technology? Since the lossy core of the device can transfer the electromagnetic energies into heat energies, the scientist expect that the omnidirectional absorber could have applications in thermal emission and electromagnetic-wave harvesting, perhaps finding its way into electronic devices, imaging systems, or heating and cooling systems.
The research was published in the New Journal of Physics.