Rydberg atom-based sensors for metrology and beyond

The unique properties of Rydberg atoms allow for radio-frequency spectroscopy, which has resulted in intriguing applications. One of the keys to developing new science and technologies is to have sound metrology tools and techniques. Atom-based measurements allow for unprecedented accuracy in measurement systems, and as a result, measurement standards have evolved towards atom-based measurements over the last few decades; most notably length (m), frequency (Hz), and time (s) standards. Recently, there has been a great interest in extending this to magnetic, electric, and other physical quantities. These Atom-based measurements allow for direct International System of Units (SI) traceable measurements.  The development of Rydberg atom-based sensors has allowed for SI-traceable measurements for E-fields and RF power. With the great progress in the development of Rydberg atom-based sensors, interesting and unforeseen applications are emerging. These applications include, 1) SI-traceable measurements for electric field and power, 2) amplitude and phase detection of time-varying signals, 3) angle-of-arrival, 4) waveforms and spectrum analyzers, 5) plasma sensors, 6) near-field and sub-wavelength imaging, 7) blackbody detection and thermometry, 8) DC/AC voltage measurements, and 9) even streaming video over the air. As well as many other applications. One of the more intriguing applications for Rydberg atom-based sensors is in the detection of time-varying signals. These atom-based receivers allow for the detection of amplitude-, frequency-, and phase-modulated signals. In fact, in receiver applications, these Rydberg-atom sensors act like an antenna (to detect the signal) and they perform the demodulation and down conversion automatically. That is, these Rydberg receivers can eliminate a lot of the front-end devices and electronics when compared to conventional receivers. The atom-based sensors have sizes on the order of 10 mm as compared to conventional antennas with sizes on the order of a wavelength of the field being detected. Atom-based sensors are in effect, truly electrically small antennas. The Rydberg atom sensors are broadband, detecting fields from a few kHz to THz, with large dynamic range (uV/m to kV/m).  In this talk, I will summarize the field of Rydberg sensors and discuss applications.