Microwave electric field (MW E-field) sensing is important for a wide range of applications in the areas of remote sensing, radar astronomy and communications. Over the past decade, Rydberg atoms have been used in ultrasensitive, wide broadband, traceable, stealthy MW E-field sensing because of their exaggerated response to MW E-fields, plentiful optional energy levels and integratable preparation methods. This review first introduces the basic concepts of quantum sensing, the properties of Rydberg atoms and the principles of quantum sensing of MW E-fields with Rydberg atoms. An overview of this very active research direction is gradually expanding, covering the progress of sensitivity and bandwidth in Rydberg atom-based microwave sensing, superheterodyne quantum sensing with microwave-dressed Rydberg atoms, quantum-enhanced sensing of MW E-field and recent advanced quantum measurement systems and approaches to further improve the performance of MW E-field sensing. Finally, a brief outlook on future development directions is provided.
Microwave electric field (MW E-field) sensing is important for a wide range of applications in the areas of remote sensing, radar astronomy and communications. Over the past decade, Rydberg atoms have been used in ultrasensitive, wide broadband, traceable, stealthy MW E-field sensing because of their exaggerated response to MW E-fields, plentiful optional energy levels and integratable preparation methods. This review first introduces the basic concepts of quantum sensing, the properties of Rydberg atoms and the principles of quantum sensing of MW E-fields with Rydberg atoms. An overview of this very active research direction is gradually expanding, covering the progress of sensitivity and bandwidth in Rydberg atom-based microwave sensing, superheterodyne quantum sensing with microwave-dressed Rydberg atoms, quantum-enhanced sensing of MW E-field and recent advanced quantum measurement systems and approaches to further improve the performance of MW E-field sensing. Finally, a brief outlook on future development directions is provided.
Microwave sensing offers important applications in areas such as data communication and remote sensing. It has thus received much attention from academia, industry, and governments. Atomic wireless sensing uses the strong response of the large electric dipole moment of a Rydberg atom in response to an external field to achieve precise measurement of a radio frequency (RF) signal. This method offers advantages over traditional wireless sensing including ultrawide energy level transitions, which makes it responsive to RF electric fields over a wide bandwidth. Here, we briefly review the progress of electric field measurement based on Rydberg atoms. We discuss the properties of Rydberg atoms, measurement using Rydberg atoms, experimental progress in electric field measurement of different bands, and different methods for detecting electric fields (such as atomic superheterodyne, machine learning, and critically enhanced measurement). The development of Rydberg atomic measurement focuses on the advantages of Rydberg atomic sensing, especially when compared to conventional microwave receivers. This work is of major significance to developing Rydberg-based measurements in astronomy, remote sensing, and other fields.
With the overall redefinition of the international system of units (SI), the classical physical standards are gradually replaced by the natural standards based on quantum physics. Due to the reproducibility, accuracy and stability of atomic system, many new technologies of quantum precision measurement have been developed based on the atomic systems. Rydberg atoms are very sensitive to external electromagnetic fields because of their large MW transition dipole moment and polarizability. With the atomic coherence effect, the ultra wideband electric field can be measured with high precision and high sensitivity. Especially for the microwave range whose frequency is higher than 1 GHz, the research of establishing microwave quantum standard is advancing steadily. In addition, all optical materials and ultra wide band atomic antenna have a wide range of applications in aerospace, military communications and other fields. In this paper, we review the researches of microwave sensing and communication based on Rydberg atoms, and introduce the progress in the quantum standard of microwave electric field strength, coherent detection, radio-over-fiber, digital communication, etc., and discuss the possible applications and research frontiers in this rapid developing field.
Rydberg atoms are neutral atoms excited to high principal quantum number states, which endows them with exaggerated properties such as large electric dipole moments, long lifetimes, and extreme sensitivity to external electromagnetic fields. These characteristics form the foundation of Rydberg atom-based sensors, an emerging class of quantum devices capable of optically detecting electric fields across frequencies from DC to the terahertz regime. Rydberg-based electrometry operates through both Autler–Townes (AT) splitting of resonant Rydberg transitions and Stark-shift measurements for high-frequency or far-detuned fields, enabling broadband field sensing from DC to the THz regime. Using ladder-type electromagnetically induced transparency (EIT) and AT splitting, these sensors enable non-invasive, SI-traceable measurements of field amplitude, frequency, phase, and polarization. Recent developments have demonstrated broadband electric field probes, voltage calibration standards, and compact RF receivers based on thermal vapor cells and integrated photonic architectures. Furthermore, innovations in multi-photon EIT, superheterodyne readout, and multi wave mixing have expanded the dynamic range and bandwidth of Rydberg-based electrometry. Despite challenges related to environmental perturbations, linewidth broadening, and laser stabilization, ongoing advances in atomic control, hybrid photonic integration, and EIT-based readout promise scalable, chip-compatible sensors. This review summarizes the physical principles, experimental progress, and emerging applications of Rydberg atom-based sensing, emphasizing their potential for next generation quantum metrology, wireless communication, and precision field mapping.
Rydberg atoms are atoms in their highly excited energy states. The physical properties of Rydberg atoms in the presence of external fields play an important role in quantum precision measurement. In recent years, radio-frequency electric field sensing based on Rydberg atoms has attracted significant interest. It is widely recognized as an electromagnetic sensing system fundamentally different from traditional ones. As a quantum sensor, it is expected to surpass several foundational limitations of traditional receivers, such as sensitivity, dynamic range and frequency bandwidth. It was reported that Rydberg sensing systems can sense microwaves of frequencies from DC up to 1THz. Its quantum nature would possibly avoid internal thermal (Johnson) noise, even at room temperature. Recent demonstrations have also observed high precision for terahertz imaging, strong fields sensing, proof-of-principle communication. However, limitations of this novel system have not been addressed, especially for a practical radar, communication or electronic warfare system. Here in this work, we first compare the architectures of different microwave receivers and then analyze the metrics of Rydberg microwave receivers, such as instantaneous bandwidth and dynamic range based on experimental results. We concluded by pointing out several main obstacles to overcome for realizing a practical state-of-the-art microwave receiver.
Rydberg-atom-based electrometry provides a quantum, SI-traceable approach to radio-frequency (RF) and microwave electric-field sensing by linking optical spectra to absolute field strength through electromagnetically induced trans parency. Over the past decade, rapid advances in excitation schemes, field-tuning methods, interferometric readout, and cavity-assisted coupling have significantly improved sensitivity, bandwidth, and tunability of Rydberg-based sensors. In parallel, progress in fiber-coupled modules, microfabricated vapor cells, and photonic integration is enabling compact and deployable receiver architectures. This review presents a comprehensive and metrology-oriented synthesis of the physical principles, system architectures, standardized performance metrics, and uncertainty considerations relevant to Rydberg-atom RF sensing. By con solidating diverse developments into a unified performance and evaluation framework, this work provides a critical reference for the design, comparison, and advancement of next-generation quantum RF sensors and standards.
Rydberg atom electric field sensors are projected to enable novel capabilities for resilient communications and sensing. This quantum sensor is small-size, highly sensitive, and broadly tunable, and it has the potential for performing precision vector electric field and angle-of-arrival measurements. While these atomic electric field sensors will not replace traditional receivers in commodity applications for RF signal reception, these sensors could be an enabling technology in niche application spaces. This review outlines the principles of operation of atomic electric field sensors and compares their performance capabilities to traditional RF receivers. It also highlights recent research and development efforts in atomic electric field sensing and identifies applications for which these sensors are projected to impact communications and remote sensing.