IEEE - Aerospace and Electronic Systems - April 2020 - 48

Feature Article:

DOI. No. 10.1109/MAES.2019.2960922

Rydberg Atoms for Radio-Frequency
Communications and Sensing: Atomic Receivers
for Pulsed RF Field and Phase Detection
David A. Anderson, Rachel E. Sapiro, Georg Raithel,
Rydberg Technologies, Inc.

INTRODUCTION
The emergence of atomic sensor technologies is driving a paradigm shift in modern sensing and measurement by exploiting quantum phenomena to realize fundamentally new
detection capabilities unmatched by their classical counterparts [1]. Atomic sensing of radio-frequency (RF) electric
fields using Rydberg electromagnetically induced transparency (EIT) in atomic vapors has been the subject of growing
scientific interest [2], [3], [4]. This has been motivated in part
by a drive at the National Metrology Institutes to replace
century-old antennas as RF standards with absolute (atomic)
standards for RF electric fields [3], Rydberg atom-based sensing has recently been established as a novel quantum technology platform with broad capabilities [5], [6] that has matured
into commercial RF detection and measurement instrumentation [7], [8]. A notable advance in atomic RF devices and
measurement tools is the recent realization of the first Rydberg RF field probe and measurement system for self-calibrated SI-traceable broadband RF measurement and imaging
of continuous, pulsed, or modulated fields. Relevant developments include the realization of compact atomic sensing elements capable of broadband RF electric field measurement
from MHz to >100 GHz [9], fiber-coupled atomic vapor-cell
RF field probes [6], [10], the demonstration of ultrawide
dynamic field ranges spanning sub-10 mV/m up to >10 kV/
m (dynamic range >120 dB) [11], [12], and all-optical
circuit-free RF sensors for EMP/EMI-tolerant detection and

Authors' current address: David A. Anderson,
Rachel E. Sapiro, Georg Raithel, Rydberg Technologies, Inc., Ann Arbor, MI 48103 USA (e-mail:
dave@rydbergtechnologies.com).
Manuscript received July 23, 2019, revised October 17,
2019; accepted December 5, 2019, and ready for
publication December 17, 2019.
Review handled by Marco Frasca.
0885-8985/19/$26.00 ß 2019 IEEE
48

operational integrity in high-intensity RF environments [13].
Hybrid atomic RF technology that combines atom-based optical sensing with traditional RF circuitry and resonators has
also been developed realizing hybrid sensors with augmented
performance capabilities such as resonator-enhanced ultrahigh sensitivity polarization-selective RF detectors [14],
waveguide-embedded atomic RF E-field measurement for
SI-traceable RF power standards [15], and atom-mediated
optical RF-power/voltage transducers and receivers [16].
Recently, Rydberg atom-based field sensing has also been
adapted to modulated RF field detection promising new possibilities in RF communications, with demonstrations including
a Rydberg-atom transmission system for digital communication [17], atom radio-over-fiber [18], and "Atomic Radio" [19]
using a multiband atomic AM and FM radio receiver based on
direct atom-mediated RF-to-optical conversion of baseband
signals picked up from modulated RF carriers [20].
In this article, we describe the basic principles of the
atomic RF sensing method and present the development of
atomic pulsed RF detection and RF phase sensing establishing capabilities pertinent to applications in communications and sensing. To date, advances in Rydberg atombased RF field sensors have been rooted in a method in
which the fundamental physical quantity being detected
and measured is the electric field amplitude, E, of the incident RF electromagnetic wave. The sections titled "Atomic
RF Electric Field Sensing" and "Communications and
Modulated RF Field Sensing With Atomic Receivers" are
focused on using atom-based E-field measurement for
RF field-sensing and communications applications. With
established phase-sensitive technologies, such as synthetic
aperture radar (SAR) as well as emerging trends in phasedarray antennas in 5 G, a method is desired that allows
robust, optical retrieval of the RF phase using an enhanced
atom-based field sensor. The section titled "Atomic RF
Phase Detectors" is focused on a fundamentally new
atomic RF sensor and measurement method for the phase
of the RF electromagnetic wave that affords all the

IEEE A&E SYSTEMS MAGAZINE

APRIL 2020
IEEE - Aerospace and Electronic Systems - April 2020

Table of Contents for the Digital Edition of IEEE - Aerospace and Electronic Systems - April 2020
