Since the beginning of this century, scientists have designed a variety of artificial metamaterials that can bend electromagnetic, acoustic, and other types of waves in ways that are not naturally possible. Now researchers at the University of Arizona have recently produced materials of this type that can be used to construct microscopes with hyper lenses to observe molecular level details, or to conceal military aircraft and even humans. The results of this study were published in the latest issue of the "Nature and Communications" online edition under the title "Negative Index Microwave Gain Medium."
According to the report of the Physicist Organization Network on January 27 (Beijing time), Hao Xin, a professor of electrical and computer engineering at the University's Millimeter Wave Circuit and Antennas Laboratory, uses a 3D printer to manufacture metal, plastic and other materials. A new material. The material resembles a porous plastic bowling ball, a small copper circuit board, and is configured in an accurate geometric model to bend waves in an unnatural way. In particular, they exhibit negative refractive index characteristics, which means that they can bend waves in reverse.
With a negative refraction prism, a tilted straw in a cup of water will appear to reverse: the part above the water will appear below the water, tilting in the opposite direction. In the future, a cape made of this material will be partially or completely invisible to a person.
Over the years, materials with a negative refractive index have presented engineers with a thorny problem: whether they are bending microwaves, light waves, sound waves, or seismic waves, they will reduce the physical wave strength. Hao Xin said: "One of the biggest problems with these metamaterials is the loss of energy, which will attenuate the waves. However, our negative-index metamaterials do not reduce energy."
In fact, after Hao Xin embedded a simple battery-powered tunnel diode (a kind of semiconductor device) and microwave nano-assembly technology in this new material, the new material will not only prevent the loss of energy, but will even strengthen the microwave in power and cause energy. Gain.
The study was funded by the Air Force Scientific Research Service (AFOSR). Hao Xin submitted this new discovery in November 2014 to a team of scientists from Duke University that promoted government, industry, and academia to promote the Army's Army, Navy, and Air Force Service Materials Program for Materials Research and Development.
Hao Xin is dedicated to microwave frequency research and can also be applied to optical, acoustic and other types of waves. At the same time, metamaterials with negative refraction and energy gain characteristics will help engineers overcome the difficulties of lens diffraction and develop microscopes that can explore proteins and viruses.
In addition to being used for biomedical and other uses, this material can also be used to develop high-performance microwave circuits, more energy-efficient and seismic-resistant buildings, more powerful solar inverters, improved sensor technology, and smaller antennas that will be used from Health monitoring to military reconnaissance all more flexible, efficient and practical wireless devices. This material is still in the testing stage. Hao Xin said with confidence: "Invisible cloak will become a reality." (Reporter Hualing)
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