Quantum sensors using Rydberg atoms enable ultrasensitive and ultrawideband electric field sensors, communication receivers from VLF to Terahertz

Quantum sensing uses some nonintuitive properties of nature to measure things like time, magnetic fields, gravity, or acceleration. Quantum sensing has become a distinct and rapidly growing branch of research within the area of quantum science and technology, with the most common platforms being spin qubits, trapped ions and flux qubits. Quantum sensors are measuring device that takes advantage of quantum correlations, such as states in a quantum superposition or entanglement, for better sensitivity and resolution than can be obtained by classical systems.

For instance small particles like cesium atoms have electrons that can be coaxed to oscillate at well-defined frequencies, just like pendulams of mechanical clocks. . Rubidium can also be used for highly precise atomic clocks, and although it is considered less accurate than cesium it is inexpensive and more widely adopted. “Because all cesium atoms or rubidium atoms are identical, they are not only very precise but their frequencies are all the same,” says Kunz. “These nonintuitive properties have applications in timekeeping and positioning, since they are used for GPS. They are also used for magnetometers that can detect submarines or munitions.”

Atom-based measurements have been successfully utilized for magnetometery, time and frequency standards, inertial force sensing, amongst others. The accuracy and repeatability of atom-based measurements significantly surpass conventional methods because the stable properties of atoms and molecules are advantageous for precision measurement. Cesium now for atomic clocks provides the primary standard for the definition of the second in the International System of Units Recently, Rydberg atoms have been introduced to measure the amplitude of radio frequency (RF) electric fields following the same rationale.

It has long been understood that the large Rydberg atom polarizability and strong dipole transitions between energetically nearby states are highly sensitive to electric fields. Because a Rydberg electron is relatively weakly bound compared to a valence state, it has a comparably stronger response to an electric field.

A new imaging system that uses a laser-excited, room-temperature atomic vapour to convert terahertz radiation to visible light has been created by researchers at the University of Durham in the UK. The system can acquire terahertz images rapidly and efficiently using a conventional high-speed camera and the new technique could make it easier to develop practical technologies that use terahertz radiation.

Similarly, the ARL team has been investigating the atoms as a platform for quantum networks. Further, according to the researchers, Rydberg atoms have been showing much progress lately in the broader scientific community, serving as qubits for quantum simulation and computing.