The spin and electronic degrees of freedom in atomic systems provide sensitive and versatile means for detecting electromagnetic fields, from DC to THz frequencies, with spatial resolutions ranging from the nanoscale to meter scale. Such sensors offer unique advantages compared to classical approaches, resulting from their intrinsic quantum nature. We review three different sensor modalities: atomic vapor magnetometers, nitrogen-vacancy-center magnetometers, and radio-frequency sensors based on Rydberg atoms. We emphasize the unique features and capabilities of these types of sensors in the context of real-world applications.
The spin and electronic degrees of freedom in atomic systems provide sensitive and versatile means for detecting electromagnetic fields, from DC to THz frequencies, with spatial resolutions ranging from the nanoscale to meter scale. Such sensors offer unique advantages compared to classical approaches, resulting from their intrinsic quantum nature. We review three different sensor modalities: atomic vapor magnetometers, nitrogen-vacancy-center magnetometers, and radio-frequency sensors based on Rydberg atoms. We emphasize the unique features and capabilities of these types of sensors in the context of real-world applications.
Electromagnetic warfare (EW) refers to military operations exploiting the electromagnetic spectrum, and includes transmitting and receiving information encoded in electromagnetic fields. In order to interpret such information, effective sensing systems are of great importance. For EW applications, the radio frequency (RF) spectrum is specifically relevant. Traditional RF receivers and transmitters rely on antennas and associated electronic components, whose performance is fundamentally limited by constraints imposed by the laws of classical physics. Motivated by the fundamental limitations of classical technologies, quantum technology has emerged as a strategic research area in many countries, with applications in computing, communication and sensing, and could therefore be useful in EW applications in the future. This thesis aims to investigate and compare two quantum sensing approaches: Rydberg atombased electric field sensors and nitrogen-vacancy center magnetometers. The goal is to evaluate their sensing principles, fundamental limitations and potential competitiveness compared to classical RF receivers. The work combines a literature review of published research in order to understand the underlying quantum mechanical principles enabling electromagnetic field sensing, with analytical comparisons of sensitivity and detection range. Classical receiver performance was modeled using thermal-noise-limited sensitivity, while quantum sensor performance was estimated using reported sensitivities from literature. Detection range calculations were performed under simplified assumptions to illustrate the differences between conventional and atom-based sensing approaches. The results show that current quantum sensors do not yet surpass state-of-the-art classical receivers in raw sensitivity. However, they offer several unique characteristics, including intrinsic calibration, wide frequency tunability and the possibility of direct field-based measurements without conventional impedance matching. The comparison further highlights the fundamentally different noise mechanisms governing classical and quantum sensing systems. Overall, quantum sensing represents a promising emerging technology for electromagnetic field detection. Although significant technical challenges remain, continued advances may enable future quantum sensors to complement or partially replace conventional RF sensing technologies.
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.
Quantum sensing is emerging as a practical means of improving sensing capabilities in consumer electronics, particularly where size, power, and noise constrain classical approaches. In this paper, we reviewed the near-term applicability of quantum sensing using a platform-and-application framework. Within this framework, we outlined the general sensing protocol and discussed the working of the four key quantum sensing platforms relevant to consumer electronics: nitrogen-vacancy (NV) centers, atomic vapor cells, Rydberg atomic sensors, and photonic quantum sensors. Through case studies involving navigation and positioning, healthcare and wearables, radio-frequency (RF) and wireless systems, the Internet of Things (IoT), and imaging, we examined the tangible engineering advantages offered by quantum sensing. Rather than replacing devices outright, quantum sensing is more likely to earn its place in the near-term by upgrading specific measurement components within hybrid classical-quantum systems. Right now, the clearest opportunities are in weak-field detection, compact RF reception, and sensing that remains robust in noise.
Quantum sensing is a paradigm shift in measurement science. It uses the intrinsic quantum properties of particles and their wave functions, such as superposition, entanglement, and coherence, to achieve unparalleled sensitivity, precision, and miniaturization. This paper provides a practical engineering perspective on quantum sensing, linking foundational quantum principles to real-world applications. It reviews key enabling technologies, such as single-photon detectors, which can detect individual photons with high efficiency and low noise; nitrogen vacancy (NV) centers in diamonds, which sense nanoscale magnetic and electric fields at room temperature; and Rydberg atoms, which detect precise electromagnetic fields using optical techniques. Additionally, we examine the integration of quantum sensing approaches with optical fiber systems, high-lighting advances in distributed sensing capabilities enabled by quantum detectors. The discussion emphasizes the advantages of quantum measurement techniques over classical methods. Finally, it outlines the emerging domain of quantum sensing applications and the ongoing miniaturization and cost reduction of quantum devices, demonstrating their potential to transform multiple scientific and industrial fields.
Quantum sensors are finding their way from laboratories to the real world, as witnessed by the increasing number of start-ups in this field. The atomic length scale of quantum sensors and their coherence properties enable unprecedented spatial resolution and sensitivity. Biomedical applications could benefit from these quantum technologies, but it is often difficult to evaluate the potential impact of the techniques. This Review sheds light on these questions, presenting the status of quantum sensing applications and discussing their path towards commercialization. The focus is on two promising quantum sensing platforms: optically pumped atomic magnetometers, and nitrogen–vacancy centres in diamond. The broad spectrum of biomedical applications is highlighted by four case studies ranging from brain imaging to single-cell spectroscopy. Quantum sensors enable new possibilities in biomedical applications due to their high sensitivity. In this Review, the status of quantum sensing is presented, and the path towards real-world applications on the molecular, cellular and organism scale is evaluated.
An antenna is a key component of E-field signal pickup. However, an antenna has major limitations due to the metal-based probes, the geometry it carries, and the use of metal transmission lines; this can lead to perturbations or disturbance of the fields which limits the precision for field sensing. Rydberg atoms such as Cesium (Cs) or Rubidium (Rb) are utilized for Rydberg sensing. This can be utilized over a large range of frequencies from DC MHz and THz upto (>100 GHz) to measure amplitude, polarization, power, phase, and Angle-of-Arrival of RF Efield. Rydberg sensor detection scheme provides a multitude of applications, including far field characterization using near field or subwavelength imaging, strong RF E-field measurements, weak field detections, mapping of microwave circuitry, Binary Phase Shift Keying (BPSK), Quadrature Amplitude Modulation (QAM) and Quadrature Phase Shift Keying (QPSK) signals, metrology, and radars. Recently, practical RF E-field probes such as the RFP and movable probe have been prototyped for application specific RF sensing and measurement needs, further, antenna and waveguide embedded Rydberg sensors have also been developed. Few limitations in the Rydberg sensing scheme are due to lasers, EIT line-width, earth magnetic effects, photodiode circuit noise, and vapor cell in-homogeneity. The purpose of the review is to brief about the thematic work done across the Rydberg atom domain and its applications as RF E-field sensors. The findings of this review indicate the advantages and applications of Rydberg atom sensing as well as the gaps and uncertainties the scheme carries.