The world’s tiniest radio

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have made the world’s smallest radio receiver, built out of an assembly of atomic-scale defects in pink diamonds. This tiny radio, whose building blocks are the size of two atoms, can withstand extremely harsh environments and is biocompatible, meaning it could work in places as varied as a probe on Venus to a pacemaker in a human heart. The research was led by Marko Loncar, the Tiantsai Lin Professor of Electrical Engineering at SEAS, and graduate student Linbo Shao, and was published in the journal Physical Review Applied. The radio uses tiny imperfections in diamonds called nitrogen-vacancy (NV) centers. To make NV centers, researchers replace one carbon atom in a tiny diamond crystal with a nitrogen atom and remove a neighboring atom — creating a system that is essentially a nitrogen atom with a hole next to it. NV centers can be used to emit single photons or detect very weak magnetic fields. They have photoluminescent properties, meaning they can convert information into light, making them powerful and promising systems for quantum computing, phontonics, and sensing.”