Chinese scientists create "artificial black hole" to absorb and utilize solar energy

According to the British magazine New Scientist, scientists have for the first time built an artificial electromagnetic "black hole" that can absorb ambient light. The device can absorb solar energy and convert it into heat or electricity for people to use.

This artificial black hole works at microwave frequencies and will soon be able to absorb visible light, which is a completely new way to harvest solar energy to generate electricity. Earlier this year, Evgenii Narimanov and Alexander Kildishev of the University of Urdu in India published a study in the journal Media that proposed a theory on how to build a tabletop black hole that can absorb light. This artificial black hole can simulate a cosmic black hole, whose strong gravity can bend the surrounding space-time, causing any surrounding matter or radiation to follow the distorted space-time and spiral inward to be absorbed.

Narimanov and Kildishev believe that this artificial black hole can bend light toward the center of the device for absorption. The artificial black hole they designed is a cylindrical structure consisting of a central column containing a coaxial ring shell. The key factor that can bend light inward is the dielectric constant of the coaxial ring shell, which can affect the electrical component of electromagnetic waves and increase the smoothness of the surface from the outside to the inside, which is similar to the curvature of space-time close to the black hole. When the coaxial ring shell contacts the central column, the dielectric constant of the coaxial ring must match the central column, so that the light can be absorbed instead of being reflected.

Currently, scientists Cui Tiejun and Chen Qiang from Southeast University in Nanjing, China, have applied Narimanov and Kildishev's theory to practice and built an "artificial black hole" at microwave frequencies. The device is constructed of 60 coaxial rings using a "super material" that has been used to make invisibility cloaks.

Each coaxial ring is formed in the form of a circuit board with different structures. The coaxial rings are connected to each other, so their dielectric constant is very smooth. The 40 coaxial rings on the outside form the shell, and the 20 coaxial rings on the inside form the absorber. Cui Tiejun said: "When the incident electromagnetic wave hits the device, the electromagnetic wave will be induced into the internal coaxial ring and then absorbed. The coaxial ring will convert the absorbed light into heat."

Narimanovi was very impressed by the artificial black hole built by the two Chinese scientists. He said: "I am very surprised that they can build an artificial black hole so quickly!"

It is not easy for this artificial black hole to capture light waves in the same way. The wavelength of visible light is much smaller than that of microwave radiation. This requires the coaxial ring to be built smaller accordingly. Cui Tiejun is full of confidence in the artificial black hole they built. He said: "I expect this optical black hole to be widely used by the end of 2009."

Artificial black holes like this one could be used to collect solar energy, especially for sunlight that is too diffuse to be focused on solar cells using solar reflectors. Optical artificial black holes would be able to completely absorb this light and transfer it directly to solar cells that absorb it on coaxial rings. "If this device works effectively, then there will be no need to use parabolic reflectors to collect sunlight in the future," Narimanović said.