Academician of the Chinese Academy of Sciences demonstrated the "Huluwa Invisibility" on site! Will science fiction become reality?

From ancient times to the present, invisibility has always been one of the dreams pursued by mankind. From the invisible helmet of the hero Perseus in ancient Greek mythology, to the Monkey King using invisibility to sneak into the Yao Chi Palace and cause a disturbance at the Peach Banquet in "Journey to the West", to the invisible cloak of the protagonist in the world-famous "Harry Potter", "invisibility" has always been widely concerned.

Recently, at the bilibili Super Science Night event, Chu Junhao, an academician of the Chinese Academy of Sciences, shared an amazing scientific discovery - using special materials to achieve invisibility .

Image source: Bilibili

This technology is not magic, but a pure scientific method. At the scene, Chu Junhao used a magical material called "cylindrical grating" that allows light to refract regularly. It is understood that the cylindrical grating is a material composed of tiny cylindrical convex lenses, and when light passes through it, it will be refracted regularly.

This special structure makes the object behind be compressed into thin strips after the light passes through. When there are enough lenses, the object will be decomposed into countless identical thin strips. Since the human eye cannot distinguish these thin strips, the object will appear to have disappeared.

In addition to cylindrical gratings, Academician Chu Junhao also demonstrated another way of invisibility - using two materials with similar refractive indices .

For example, the refractive index of borosilicate glass and glycerol is similar. When an object made of borosilicate glass moves in glycerol, it can also achieve an invisible effect.

This method of using the difference in the refractive index of materials to hide objects opens up more possibilities and demonstrates the magic of stealth technology.

“Everyone is invisible” is no longer a fantasy?

In a narrow sense, "invisibility" only means being invisible to the naked eye. In a broader sense, invisibility is not limited to the naked eye, but refers to being invisible to certain detection methods (such as radar and sonar). Invisibility is called invisibility under such detection methods. Stealth technology has also become a research focus of various countries in the military field. With the continuous development of scientific theories, stealth technologies such as infrared invisibility and radar invisibility have been more maturely applied in the military field.

With the continuous evolution of infrared detection technology, the development of infrared stealth technology has also entered the fast lane. In 2008, the concept of metamaterials and related research expanded to the field of thermal science, providing a new direction for the selection of materials for thermal stealth devices - thermal metamaterials.

In addition, scientists are also conducting extensive and in-depth explorations on the invisibility of matter in different physical environments, and have constructed different types of invisibility cloaks, such as electromagnetic wave invisibility cloaks that achieve invisibility at specific microwave wavelengths, acoustic invisibility cloaks that prevent objects from affecting the propagation of sound waves, and thermal invisibility cloaks made using heat flow propagation equations.

Behind the fantasy of trying to make oneself invisible is the human desire for the unknown. And this vision of the future will become the driving force for the continuous progress of science.

Comprehensive sources: Xinhuanet, China News Network, Bilibili, etc.