Scientists Use Silk Material To Make Invisibility Cloaks.

Recently, scientists have used silk to make a cloak of invisibility. Although the invisibility cloak can only play a role in the spectral range between radio waves and infrared rays beyond visible light, scientists at Boston University and Tufts University believe that through improvement, they may make it work in a shorter range of light, or even visible light.

　　
Researchers hope that this material will have both medical value and invisibility of human beings or objects. This "metamaterial" is made of silk covered with a metallic material. Each tiny helix is a "split ring resonator". The split ring resonator has a unique effect on light: they can absorb or reflect light within a specific wavelength range or bend light so that they can be bypassed from the surface of the object. Each square centimeter of silk metamaterials has 10 thousand open loop resonators.

　　
Usually terahertz waves can pass through silk without any effect on them. But when terahertz waves come into contact with this new type of metal silk, the latter resonates. Because silk is biocompatible and does not cause immune rejection after implantation into the body, it can be widely used in the medical field. Fiorenzo Omenetto, a researcher at Tufts University, said: "for the metamaterials, this is a unique perspective, because silk has the ability to be compatible with the human body."

　　
Researchers say that using this material to make Harry Porter type cloak is only one aspect, and it can be applied to the medical field to maximize its value. Radiological researchers can use this material to cover organs so as to better see the part of the organ being obstructed. Diabetics can also use it as a glucose sensor: when the level of blood sugar changes, this metamaterial will change accordingly. This change can be launched in the form of radio waves, and it can be found by mobile phone.

　　
Last year, researchers from the Royal College of University of London and University of Southampton received a grant of 4 million 900 thousand pounds (51 million 983 thousand and 800 yuan) and obtained permission to study the metamaterials and their applications in the fields of medicine, defense, security and communication.