In a major scientific breakthrough, physicists at the University of Warsaw have successfully filled the long-standing “terahertz gap”, a blind spot in electromagnetic measurement that has challenged researchers for decades. This achievement could unlock transformative advances in 6G wireless communication, medical imaging, security scanning, and industrial sensing.
Terahertz radiation lies between microwaves and infrared light on the electromagnetic spectrum. Its unique position made it notoriously difficult to measure—too fast for conventional electronics and too slow for optical techniques. As a result, progress in terahertz-based technologies remained stalled, despite their enormous potential.
The Warsaw research team solved this problem by turning rubidium atoms into quantum antennas. By exciting a single electron within the atom to an extremely high-energy orbit—known as a Rydberg state—the atom becomes unusually large and extraordinarily sensitive to tiny electric fields. In this “swollen” state, the atom can detect terahertz signals with unprecedented precision.
The most remarkable achievement of the experiment was the first-ever measurement of a single “tooth” of a terahertz frequency comb. Frequency combs act like ultra-precise electromagnetic rulers and were recognized with the 2005 Nobel Prize in Physics. Until now, individual teeth of such combs in the terahertz range had never been directly observed.
The researchers achieved this by combining Rydberg atom-based detection with a terahertz-to-visible-light conversion technique, reaching sensitivity down to the single-photon level. Even more significantly, the entire system operates at room temperature, unlike many quantum technologies that require ultra-cold environments. This dramatically increases its potential for real-world applications and commercial use.
Experts say this breakthrough establishes reliable reference standards for next-generation terahertz technologies. It could accelerate the development of ultra-fast 6G networks, enable non-invasive medical imaging capable of seeing beneath the skin without harmful radiation, and improve airport security scanners and industrial quality control systems.
