Quantum Radar: A Paradigm Shift in Detection Technology
Traditional radar relies on transmitting electromagnetic waves and receiving reflected signals to locate targets, with detection sensitivity fundamentally limited by quantum noise (shot noise). Quantum radar uses photon pairs in quantum entanglement tobreak throughthis limit — even if only a single photon returns from the target, target information can be extracted through correlation analysis with the entangled photon on the other path.
In 2025, the Pan Jianwei team at the University of Science and Technology of China published the most complete experimental results to date for a microwave-optical conversion quantum radar. The system achieved effective detection distance approximately 3 times that of classical radar for metallic targets in outdoor environments, and could reliably identify targets under strong background noise (signal-to-noise ratio of 0.1). The key breakthrough was using nonlinear crystals to achieve quantum state conversion between microwave and optical frequency bands — the core bottleneck for bringing quantum entanglement advantages from the laboratory into practical applications.
Quantum radar's threat to stealth technology is structural. Current stealth aircraft and naval vessels — whether through specializedexterior shapedesign (reducing radar cross-section RCS) or radar-absorbent material coatings — are optimized against classical radar signal characteristics (frequency, polarization, pulse waveform). Quantum detection methods exploit completely different physical mechanisms, and classical stealth design's effectiveness against them has not been systematically verified.
However, deploying quantum radar in actual combat systems still faces severe challenges. Entangled photon pairs rapidly decohere in the atmosphere due to scattering and absorption, with effective range dropping sharply in rain and fog. Current prototype systems' size and power consumption also fall far short of tactical deployment standards — laboratory systems occupy an entire optical table (approximately 3 square meters) with power consumption exceeding 5 kW.
Furthermore, countermeasures against quantum radar are developing in parallel. Theoretical research suggests that quantum limiting amplifiers can partially restore classical stealth technology's defensive effectiveness against quantum detection. This means quantum radar's actual combat advantage may be less than theoretical predictions.
In terms of competitive dynamics, China, the United States, and the European Union are all investing heavily in quantum radar. The U.S. Defense Advanced Research Projects Agency's (DARPA) "Quantum Sensors Program" budget for 2025 was approximately $180 million. China's National Laboratory for Quantum Information has also listed quantum radar as a priority research direction. It is estimated that between 2028 and 2030, the first miniaturized, low-power quantum radar prototypes may enter operational testing.
Disclaimer: This article is written by POC.HK Future Technology Observatory based on publicly available academic papers and independent analysis, and does not constitute any form of military technology assessment.