In a remarkable leap forward for underwater detection technology, a team of Chinese scientists has introduced an advanced radar system capable of identifying objects deep under the sea with unprecedented clarity. This breakthrough has not only earned accolades from international journals but also promises to revolutionize maritime exploration, environmental monitoring, and even military operations. Imagine “fishing for a needle in the sea” that’s how precise this technology is.
This cutting-edge research, published in the prestigious international journal Applied Optics and the Chinese academic journal Modern Radar, is set to reshape how we explore and understand the ocean’s hidden depths. But how does it work, and why is it such a game-changer? Let’s dive in.
Award-Winning Radar: A Needle in the Ocean
Standing out among 1,278 submissions, the research paper led by, an associate professor at Xiamen University, has been recognized as the best paper of the year by the international journal Applied Optics. The team developed a radar technology that employs high-energy microwave synthesis to create a radio-emitting source in the sky, known as a “ghost radar.”
This virtual signal source travels at near-light speed, emitting electromagnetic waves that penetrate deep into the ocean. Thanks to the innovation discovered in July 2023. Now, submarines hidden hundreds of meters underwater can be detected with remarkable accuracy.
The Power of Extremely Low-Frequency (ELF) Waves
The secret behind this breakthrough lies in extremely low-frequency (ELF) waves. Unlike traditional radar waves, ELF waves can penetrate seawater, enabling the detection of submarines and other objects concealed in the ocean’s depths. The ability to detect objects hundreds of meters below the surface gives this technology a significant edge, particularly in military and scientific applications. But the team didn’t stop there.
The World’s First Single-Photon Raman Lidar System
In a paper published in 2023, the researchers unveiled the World’s first single-photon Raman lidar system capable of operating at depths of 1,000 meters (about 3,280 feet) below sea level. For those unfamiliar, lidar stands for light detection and ranging. It uses lasers to measure distances to objects with extraordinary precision.
This single-photon lidar system overcomes the typical challenges of oceanic detection, such as high power consumption and bulky equipment. The highly sensitive, low-noise detector works even in low-light conditions, making it ideal for deep-sea exploration.
Why Raman Scattering Matters
Raman scattering a phenomenon where laser light interacts with materials, causing vibrational changes plays a crucial role in this system. It helps identify substances like oil spills and dissolved CO₂, making the technology invaluable for environmental monitoring and disaster prevention.
According to the study, the system successfully detected underwater oil spills from a distance of 12 meters (about 39.4 feet) using a tiny 1-microjoule laser pulse and a 22.4mm telescope.
Miniaturization and High Integration: A Game-Changer
The radar system, detailed in a report by Optica, a professional society in the US, is characterized by its miniaturization and high integration. The experimental setup involved a radar measuring just 40cm (about 15.7 inches) in length and 20cm (about 7.87 inches) in diameter, with a power consumption of less than 100 watts.
This compact design allows the radar to deploy at depths of up to 1,000 meters, opening up potential applications in:
- Underwater Material Identification
- Coral Detection
- Manganese Nodule Exploration
- Military Reconnaissance
- Submarine Detection
A Future in Autonomous Underwater Vehicles (AUVs)
The research team isn’t resting on their laurels. According to Shangguan Mingjia, the next step is to develop a Raman lidar system using a shorter-wavelength laser, such as a blue laser, to reduce interference from chlorophyll fluorescence. Additionally, the team plans to integrate this system into autonomous underwater vehicles (AUVs).
This integration will enhance the capabilities of AUVs in marine surveys, deep-sea resource exploration, and environmental monitoring.
Decoding Doppler Signals for Near-Light-Speed Motion
One of the most fascinating aspects of this technology is its ability to simulate near-light-speed motion using Doppler signals. The Doppler effect where wave frequency changes based on relative motion is harnessed by an array structure that approximates high-speed motion step by step. This reduces the signal frequency and broadens the signal pulse width, making detection more efficient.
According to the scientists’ calculations, this technology could facilitate communication between surface ships and submarines, over distances of up to 3,700 miles (6,000 km). Ground-based tests have already verified the technology. The team aims to shorten the emitting array to 30 meters for more flexible deployment.
A Legacy of Innovation
For the past three years, Shangguan and his team at the National Key Laboratory for Coastal and Ocean Environmental Science have been at the forefront of underwater lidar development. Their efforts have resulted in several innovative systems and over 50 national invention patents as well as one US patent.
These radar systems are already integrated into Xiamen University’s Jia Geng research vessel, AUVs, and drones. They play a crucial role in:
- Marine Surveys
- Deep-Sea Exploration
- Environmental Monitoring
- Underwater Imaging and Target Recognition
A New Era of Underwater Discovery
This breakthrough marks the beginning of a new era in underwater detection. Whether for oil spill prevention, marine archaeology, or military reconnaissance, the potential applications are vast and transformative.
As technology advances, we may soon see even more compact, efficient, and powerful systems that push the boundaries of what’s possible beneath the waves.
What’s Next? Stay Tuned for More Breakthroughs
The Ocean holds many secrets, and with technologies like these, we are getting closer to uncovering them. From exploring deep-sea resources to protecting our environment, the future of underwater discovery looks brighter and clearer than ever before.
