Atomic Radios

Radio was invented in 19th century. Everyone knows the principle. Radio waves are an electromagnetic field. Then there is the antenna. Radio waves induce a small current in the antenna. The current is then amplified and processed to deliver the encoded information. Antennas have always been inherent to radios. In fact you can attach a piece of wire to an earpiece from an old telephone handset and that is sufficient to receive AM-modulated signal if you are close to the transmitter (this was the first "radio" I built as a young boy).

There is a totally new approach to receiving radio frequency (RF) signals. The approach based on quantum physics and special behaviors of single atoms. Called Rydberg Atomic Quantum Receivers (RAQRs) the technology has really mind blowing prospects.

RAQRs involve Rydberg atoms (atoms in highly excited states, achieved with lasers). The excited electrons appear to be sensitive to RF signals. Rydberg atoms can absorb energy of RF signals to transit to slightly different energy levels. The received RF signal causes a split of spectrum of the trigger "probe" laser beam, and the signal strength is related to the amount of split, which then can be measured by a photodetector.

RAQRs will clearly revolutionize radio receivers. In principle they operate on single atoms, so without the need for an antenna, the potential to miniaturize the circuits is enormous. Then based on the theory and initial tests, RAQRs can achieve sensitivity that is 100 times better compared to antenna-based receivers. 

Eliminating the antenna and going down to atomic scale will be the future of radios. Actually, this future is around the corner: in early 2024 BT conducted a Microsoft Teams call using RAQR radios. And it was standards compliant 3-way call was held between London, Ipswich and Felixstowe, using the 4G spectrum.