We provide an overview of the recent progresses on the system architecture design and performance prediction for microwave signal detection under weak signal intensity regime, up to quantumized level. The technique roadmap includes two perspectives, the opto-electro-mechanical (OEM) and superconducting devices. For the former one, we first overview the concept of OEM, and then introduce the signal detection based on capacitive-opto-electro-mechanical systems and piezo- opto-electro-mechanical systems. For the latter one, we first overview the concept and architecture of Josephson junction, and then introduce the signal detection based on superconducting Hanbury Brown-Twiss (HBT) experiments and Λ energy-level splitting system. Besides, we review the microwave detection based on Rydberg atom system. We believe that this overview can provide a guidance for future transmission limit, signal processing, detection device fabrication and real experiments.
We provide an overview of the recent progresses on the system architecture design and performance prediction for microwave signal detection under weak signal intensity regime, up to quantumized level. The technique roadmap includes two perspectives, the opto-electro-mechanical (OEM) and superconducting devices. For the former one, we first overview the concept of OEM, and then introduce the signal detection based on capacitive-opto-electro-mechanical systems and piezo- opto-electro-mechanical systems. For the latter one, we first overview the concept and architecture of Josephson junction, and then introduce the signal detection based on superconducting Hanbury Brown-Twiss (HBT) experiments and Λ energy-level splitting system. Besides, we review the microwave detection based on Rydberg atom system. We believe that this overview can provide a guidance for future transmission limit, signal processing, detection device fabrication and real experiments.
Future wireless communication system embraces physical-layer signal detection with high sensitivity, especially in the microwave photon level. Currently, the receiver primarily adopts the signal detection based on semi-conductor devices for signal detection, while this paper introduces high-sensitivity photon-level microwave detection based on superconducting structure. We first overview existing works on the photon-level communication in the optical spectrum as well as the microwave photon-level sensing based on superconducting structure in both theoretical and experimental perspectives, including microwave detection circuit model based on Josephson junction, microwave photon counter based on Josephson junction, and two reconstruction approaches under background noise. In addition, we characterize channel modeling based on two different microwave photon detection approaches, including the absorption barrier and the dual-path Handury Brown-Twiss (HBT) experiments, and predict the corresponding achievable rates. According to the performance prediction, it is seen that the microwave photon-level signal detection can increase the receiver sensitivity compared with the state-of-the-art standardized communication system with waveform signal reception, with gain over 10dB.
We adopt artificial$\Lambda $-type three-level system with superconducting devices for microwave signal detection, where the signal intensity reaches the level of discrete photons instead of continuous waveform. Based on the state transition principles of the three-level system, we propose a statistical model for microwave signal detection. In addition, achievable transmission rates and signal detection based on the proposed statistical models are investigated for low temperature conditions in deep space communication scenario. It is predicted that high sensitivity can be achieved by the proposed system. We further characterize the received signal considering the saturation phenomenon of three-level system, which reveals negligible performance degradation caused by saturation under weak received power regime.
Photon-level Quantumized Microwave Detection Based on Artificial Λ-Type Three-level System with Superconducting Devices: Performance Prediction
We adopt artificial Λ-type three level system with superconducting devices for microwave signal detection, where the signal intensity can reach the level of discrete photons instead of continuous waveform. Based on the state transition principles, we propose a statistical model for microwave signal detection. Moreover, we investigate the achievable transmission rate and signal detection based on the statistical model. It is predicted that the proposed detection can achieve significantly higher sensitivity compared with the currently deployed 4G communication system.
Quantum radar has emerged as a promising sensing paradigm that exploits quantum resources, including entanglement and quantum correlations, to enhance target detection in noisy and lossy environments. Although entanglement generated by superconducting devices such as Josephson parametric amplifiers, Josephson parametric converters, and Josephson traveling-wave parametric amplifiers is rapidly degraded under realistic propagation conditions, the remaining quantum correlations can still provide a measurable detection advantage through the principles of quantum illumination. This review presents a comprehensive engineering perspective on quantum radar, covering the theoretical foundations of quantum illumination, microwave entanglement generation, electro-optomechanical quantum transducers, atmospheric channel effects, cryogenic receiver architectures, and digital signal-processing techniques. Recent microwave experimental demonstrations are also reviewed, highlighting the transition from theoretical concepts to laboratory-scale implementations. Collectively, these developments demonstrate that microwave quantum radar is evolving toward practical sensing architectures while emphasizing the engineering challenges that must be addressed before real-world deployment.
Abstract Quantum transduction, the process of converting quantum signals from one form of energy to another, is an important area of quantum science and technology. The present perspective article reviews quantum transduction between microwave and optical photons, an area that has recently seen a lot of activity and progress because of its relevance for connecting superconducting quantum processors over long distances, among other applications. Our review covers the leading approaches to achieving such transduction, with an emphasis on those based on atomic ensembles, opto-electro-mechanics, and electro-optics. We briefly discuss relevant metrics from the point of view of different applications, as well as challenges for the future.
Based on the characteristics of superposition, entanglement, non-locality and non-clonality of quantum mechanics, quantum information science can break through the physical limits of classical information and open up a new information processing function different from classical electromagnetic application methods. Due to the advantages of high-energy single photon in practical applications, the research and application of optical quantum information technology dominates the development of current quantum information technology. However, the free-space transmission of light waves is greatly affected by weather conditions and atmospheric particles. Comparing with other wave bands, classical microwave signal shows good penetration ability when transmitting in free space. By introducing quantum mechanics, microwave signal also exhibits non-classical merits. As quantum microwave signal inherits both classical transmission performance and quantum non-classical features, it can be utilized as a significant signal source for diverse applications in microwave domain, such as quantum communication, quantum navigation and quantum radar, which are based on quantum technologies in large scale and dynamic free space transmission. There are three main experimental platforms on which quantum microwave is studied and produced. They are cavity quantum electrodynamics(C-QED) system, circuit quantum electrodynamics(c-QED) system, and cavity electro-opto-mechanical(EOM) system, involving with several nonlinear effects such as Kerr effect, Casimir effect, three-wave mixing, etc. In this paper, the setups of these platforms and the preparation principles are introduced. Meanwhile, the preparation principles and methods of microwave single photon, entangled microwave photons, squeezed microwave fields and entangled microwave fields are summarized and analyzed in detail from three aspects. The present status of experimental progress in the relevant fields are summarized and listed as well. Besides, key problems in the application of quantum navigation in free space utilizing quantum microwave are probed. Among them, the most pressing ones are preparation ability, decoherence in transmission and detection of entangled quantum microwave signals, which are also discussed and analyzed in this paper. Finally, we look forward to the future development of quantum microwave technology. It mainly consists of manufacturing microwave detectors with high efficiency, designing thermal photon filters, and developing suitable antennas. We hope that this study can provide useful reference for scholars who are engaged in or interested in research related to quantum microwave technologies.