Quantum radio receiver uses laser light and atomic resonance to detect microwaves

Quantum radio receiver uses laser light and atomic resonance to detect microwaves
by Robert Schreiber
Berlin, Germany (SPX) Oct 17, 2025

Researchers at the University of Warsaw's Faculty of Physics and the Centre for Quantum Optical Technologies (QOT) have created a new class of all-optical radio receivers that operate using the quantum properties of Rydberg atoms. Powered entirely by laser light, the system eliminates traditional metal antennas and offers self-calibrating, ultra-sensitive detection of radio signals.

The breakthrough, described in Nature Communications, represents a major advance in quantum sensor technology. The team - including Sebastian Borowka, Mateusz Mazelanik, Wojciech Wasilewski, and Michal Parniak - demonstrated that by exciting rubidium atoms into Rydberg states using precision-tuned lasers, radio waves could be detected through shifts in the atoms' emission of infrared light. The phase and amplitude of this emitted light directly reflect the properties of the incoming radio signal.

Traditional radio receivers depend on metallic antennas that absorb electromagnetic energy and convert it into electrical currents, followed by frequency mixing and digital processing. The Warsaw team instead replaced these electronics with a quantum "artificial aurora" - a vapor cell containing rubidium atoms illuminated by three tightly controlled lasers. Each laser is stabilized within optical cavities that ensure precise frequency alignment, while a reference laser and nonlinear crystal provide internal calibration for optical heterodyne measurements.

As Dr. Michal Parniak explained, "in our experiments, we replaced the antenna and electronic mixer with a new medium - a kind of artificial aurora borealis." Within this setup, Rydberg electrons act as resonant detectors whose trajectories are altered by microwaves. The resulting shifts in emitted infrared light are then measured optically, allowing direct retrieval of the radio wave's phase and amplitude without physical contact or electronic interference.

Because no metal components are present inside the rubidium cell, the detector does not disturb surrounding electromagnetic fields, enabling completely non-invasive monitoring. The researchers envision future versions of the receiver miniaturized to the scale of a fiber-optic thickening, capable of relaying both laser input and signal output through optical fibers for remote sensing applications.

This quantum receiver opens up new possibilities for calibrating microwave fields and performing precision measurements where traditional antennas would introduce unwanted perturbations. Potential applications range from stealth electromagnetic monitoring to ultra-sensitive measurement systems in space and defense technologies. The technology's inherent precision and low interference profile have already drawn interest from metrology institutes, military research centers, and space agencies exploring Rydberg sensors for orbital platforms.

Research Report:Optically-biased Rydberg microwave receiver enabled by hybrid nonlinear interferometry