Researchers for the US army built the quantum sensor, which can sample from zero frequency up to 20GHz, detecting AM and FM radio, Bluetooth, Wi-Fi and other communication signals along the way.

Dubbed the 'Rydberg sensor', it uses laser beams to create highly excited Rydberg atoms directly above a microwave circuit, to boost and hone in on the portion of the spectrum being measured. The Rydberg atoms are sensitive to the circuit’s voltage, enabling the device to be used as a sensitive probe for the wide range of signals in the RF spectrum.

“All previous demonstrations of Rydberg atomic sensors have only been able to sense small and specific regions of the RF spectrum, but our sensor now operates continuously over a wide frequency range for the first time,” said researcher Dr Kevin Cox.

“This is a really important step toward proving that quantum sensors can provide a new and dominant set of capabilities for our soldiers, who are operating in...