Today, there are already several effective technologies for amplifying and detecting weak microwave signals, and some of them make it possible to detect even a single microwave particle (photon), but they require the use of superconducting materials cooled almost to the temperature of absolute zero, the Technion researchers were able to increase the necessary cooling by more than 50 degrees
Microwave radiation is a common phenomenon in nature and in many artificial devices. It is radiation whose wavelength is on the spectrum between a millimeter and a meter. One of the dramatic manifestations of such radiation in nature is the cosmic background radiation, which was discovered in the 60s and provides a lot of information about the big bang that produced it. In everyday use, we are especially familiar with the microwave device, which allows us to heat food at high speed, but waves of this type are also used in other fields, including cellular communication, deep space communication, dark matter detection, as well as devices for quantum technologies (communication, computing and sensing). Many of the advanced technological applications are based on microwave signals Weak very much, that detecting them in real time is a very complex technological challenge. Therefore, many research groups are working on developing ways toman up of microwave radiation. It is of course important that this gain does not add significant noises that would interfere with the reproduction of the original signal.
Today there are already several effective technologies for amplifying and detecting weak microwave signals, and some of them make it possible to detect even a single microwave particle (photon), but they require the use of superconducting materials cooled to a temperature of about 10 millikelvin. Another possible technology is maizer - A device similar to a laser but based on microwave radiation. This technology, which was already developed in the middle of the 20th century, has many advantages, including extremely low noise and resistance to strong pulses of microwave radiation. This technology was used, among other things, to detect the cosmic background radiation as well as to communicate with spacecraft outside the solar system. However, maser technology requires cooling the system to a temperature close to absolute zero, since when masers operate at a temperature above 1 Kelvin, they create a lot of noise that does not allow for accurate and reliable information about the original microwave radiation.
The heat and the noise
These two shortcomings - temperature and noise - are answered in a study published by the Shulich Faculty of Chemistry researchers in the journal Science Advances. The research, which was done as part of Dr. Alex Sherman's doctoral thesis under the guidance of Prof. Aaron Blank, presents a relatively quiet maser device that operates at temperatures higher than the boiling point of nitrogen (-195.8 degrees Celsius), i.e. well above 1 Kelvin. The maser is based on diamond crystals and one of the defects that characterize them - Nitrogen-vacancy center. Diamonds are carbon atoms that have been compressed under high pressure and thus fixed in an ordered crystal, and the said defect includes a nitrogen atom that replaces one of the carbon atoms and next to it his absence of a carbon atom where it is "supposed" to be. This defect has unique properties that the researchers took advantage of to make it an efficient and noiseless maser that amplifies microwave signals. According to the researchers, the new device can be used to demonstrate additional phenomena such as multiple echoes and superradiation, which may be essential in quantum electrodynamics, and it can also be used as an oscillator - a wave generator. In their estimation, the aforementioned development will lead to new achievements in quantum science, engineering and various physical applications.
The research was supported by the National Science Foundation and the Innovation Authority as part of a research in cooperation with the ALTA company of the aerospace industry.
For an article in Science Advances
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