The “quantum Radar” seeks to harness quantum entanglement and squeezing to improve the detection of faint targets beyond the best possible classical sensor. The major challenge of the quantum Radar is the very large optical loss of the target beam, which induces vacuum fluctuations and hampers the quantum correlation. In addition, the faint target reflection requires the use of high power beams, which favors high-power stimulated sources of coherent squeezed light over spontaneous low power sources of entangled photons. I will present the lossy SU1,1 nonlinear interferometer with coherent seeding as a candidate for quantum Radar sensing. I will highlight the quantum features of this sensor and report a demonstration of the quantum enhanced interference contrast, even in the presence of high loss.
The “quantum Radar” seeks to harness quantum entanglement and squeezing to improve the detection of faint targets beyond the best possible classical sensor. The major challenge of the quantum Radar is the very large optical loss of the target beam, which induces vacuum fluctuations and hampers the quantum correlation. In addition, the faint target reflection requires the use of high power beams, which favors high-power stimulated sources of coherent squeezed light over spontaneous low power sources of entangled photons. I will present the lossy SU1,1 nonlinear interferometer with coherent seeding as a candidate for quantum Radar sensing. I will highlight the quantum features of this sensor and report a demonstration of the quantum enhanced interference contrast, even in the presence of high loss.
One of the major scientific thrusts from recent years has been to try to harness quantum phenomena to dramatically increase the performance of a wide variety of classical information processing devices. These advances in quantum information science have had a considerable impact on the development of standoff sensors such as quantum radar. In this paper we analyze the theoretical performance of low-brightness quantum radar that uses entangled photon states. We use the detection error probability as a measure of sensing performance and the interception error probability as a measure of stealthiness. We compare the performance of quantum radar against a coherent light sensor (such as lidar) and classical radar. In particular, we restrict our analysis to the performance of low-brightness standoff sensors operating in a noisy environment. We show that, compared to the two classical standoff sensing devices, quantum radar is stealthier, more resilient to jamming, and more accurate for the detection of low reflectivity targets.
Quantum illumination radars rely on quantum sources of two-mode squeezing vacuum to produce signals with quantum-enhanced correlations. The recent demonstration of quantum radar transmitters in the laboratory has shown promising progress in the technology. Amplification of the faint quantum signals is however necessary in order to make quantum radars practical. Here we discuss the possibility of amplifying quantum signals while preserving a quantum advantage. We find that amplifying both signals equally cannot beat an ideal source of classically correlated signals, but does provide a quantum advantage over noisy classical sources. We also briefly discuss other amplifications scheme that may provide further enhancements.
In this study, some important parts of a quantum radar are designed using the quantum electrodynamics theory and significantly focused on entanglement conservation. Quantum radar is generally defined as a detection sensor that utilizes the microwave photons like a classical radar and simultaneously employs quantum phenomena to improve detection, identification, and resolution capabilities. However, the entanglement is so fragile, unstable, and difficult to preserve for a long time. Also, more importantly, the entangled states have a tendency to leak away due to the noise. The points mentioned enforces that the entangled states should be carefully studied at each step of the quantum radar detection processes such as the creation of the entangled photons in the tripartite system, the amplification of the photons, the propagation into the atmosphere, and the reflection from the target. At each step, the parameters related to the real mediums and target material can affect the entangled states to leak away easily. The results of simulations indicate that the features of the tripartite system and amplifier are so important to lead the detected photons to remain entangled with the optical modes. Nonetheless, it is found that a lot of entangled photons lose the related non-classical correlation.
Quantum radar represents a major shift in sensing by leveraging quantum correlations and entanglement to detect targets beyond the line of sight in complex environments. Unlike classical radar, which suffers severe performance loss in dense urban areas due to multipath effects, clutter, and noise, quantum radar uses biphoton correlations to preserve strong detection sensitivity even under heavy interference. This chapter presents a comprehensive review of quantum radar systems, focusing on NLOS functionality. It describes key concepts such as biphoton generation through spontaneous parametric down-conversion, quantum illumination methods, and optimal detection strategies. Practical implementations using cryogenic superconducting nanowire single-photon detectors and AI-based signal processing are also discussed. The role of quantum radar in future 6G integrated sensing and communication frameworks is explored, highlighting uses in autonomous vehicle safety and smart city monitoring. Simulation studies show detection rates above 95% at a 1 km NLOS distance, with up to a tenfold SNR improvement over classical systems, while experiments demonstrate more than 20 dB of noise reduction. The chapter concludes by addressing ongoing challenges like decoherence, scalability, and standardization, and outlines a pathway toward deployable quantum radar technologies by 2030 for Industry 5.0 applications.
This paper presents the advantages and limitations of a quantum radar system. The use of entangled photons to interrogate a region of space where a target is supposed to be, gives a lower probability of error than using a classical signal. This is possible because of the extra information that the quantum entanglement property can give us. This information helps us to distinguish between the signal reflected from the target and the background noise. Finally, through simulations, it is shown that the actual advantage of the quantum radar is the ability to detect a target in a high-losses and high-noise environment using a weak signal.
Quantum radar represents a major shift in sensing by leveraging quantum correlations and entanglement to detect targets beyond the line of sight in complex environments. Unlike classical radar, which suffers severe performance loss in dense urban areas due to multipath effects, clutter, and noise, quantum radar uses biphoton correlations to preserve strong detection sensitivity even under heavy interference. This chapter presents a comprehensive review of quantum radar systems, focusing on NLOS functionality. It describes key concepts such as biphoton generation through spontaneous parametric down-conversion, quantum illumination methods, and optimal detection strategies. Practical implementations using cryogenic superconducting nanowire single-photon detectors and AI-based signal processing are also discussed. The role of quantum radar in future 6G integrated sensing and communication frameworks is explored, highlighting uses in autonomous vehicle safety and smart city monitoring. Simulation studies show detection rates above 95% at a 1 km NLOS distance, with up to a tenfold SNR improvement over classical systems, while experiments demonstrate more than 20 dB of noise reduction. The chapter concludes by addressing ongoing challenges like decoherence, scalability, and standardization, and outlines a pathway toward deployable quantum radar technologies by 2030 for Industry 5.0 applications.