Harvard scientists builds world’s smallest radio receiver using atomic-scale components

Scientists Build World's Tiniest Radio Receiver Using Atomic-Scale Parts-1

A team of Harvard scientists have created the world’s tiniest radio receiver using components about the size of two atoms. Made from an assortment of microscopic defects in pink diamonds, the contraption can weather extreme environmental conditions, making it suitable for use on hostile planets, like Venus. What’s more, its biocompatible and is therefore safe to be used inside a pacemaker within the human body.

Recently published in the Physical Review Applied journal, the research was conducted by a team from Harvard’s John A. Paulson School of Engineering and Applied Sciences, with Marko Loncar and Linbo Shao as the leaders. Central to the machine’s functioning are atomic-scale imperfections inside pink diamonds, also known as nitrogen-vacancy (NV) centers. To create these defects, the scientists replaced one of the eight carbon atoms in the diamond crystal with a nitrogen atom, while also removing an adjacent atom.

Scientists Build World's Tiniest Radio Receiver Using Atomic-Scale Parts-2

This in turn produced a system containing a nitrogen atom with a similar-sized hole next to it. These NV centers, the researchers state, are capable of discerning very weak magnetic fields as well as emitting single photons. Thanks to their distinct photoluminescent properties, these structures can easily convert data to light, as is essential in quantum computing, sensing and photonics.

A radio, the team goes on to explain, is made up of five, basic parts: a power source, a receiver for turning incoming radio waves into usable signals, a transducer that converts electromagnetic waves into low-frequency current, a speaker or a pair of headphones which turn the current into sound and finally, a tuner. The newly-developed contraption relies on green light emanating from powerful lasers to power the electrons present in the NV centers.

Being sensitive to high-frequency electromagnetic fields, the electrons in the defects swiftly convert the incoming radio waves into audio signals, which then are transmitted as red light. Following this, a tiny photodiode turns the light into low-frequency alternating current that is later converted back to sound by means of a speaker or headphones.

For the purpose of tuning, the device uses an electromagnet to generate a powerful magnetic field all around the pink diamond, thus allowing the user to change the radio station. Interestingly, this microscopic radio functions with the help of only one NV center, which in turn emits a single photon at any given time, rather than a stream of photons. During laboratory testing, the researchers were able to play music even at 350 degrees Celsius (around 660 degrees Fahrenheit). Speaking about the breakthrough, Loncar said:

Diamonds have these unique properties. This radio would be able to operate in space, in harsh environments and even the human body, as diamonds are biocompatible.

Source: Harvard University 

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