Rydberg atom-based sensors for metrology and beyond

Atom-based measurements enable unprecedented accuracy and allow for direct International System of Units (SI) traceable measurements. As a result, metrology techniques and measurement standards have evolved towards atom-based measurements over the last few decades (time, frequency, length). Recently, there has been a great interest in extending this to magnetic fields, electric fields, and other physical quantities. The unique properties of Rydberg atoms allow for radio-frequency metrology and spectroscopy, leading not only to accuracy improvements but also to a range of intriguing applications.