The lidar system developed by Xiamen University can operate at depths of one kilometer and detect oil spills from a distance of 12 meters.
A research team from Xiamen University has developed a single-photon Raman lidar system. This radar technology can detect objects at impressive depths, akin to the challenge of “finding a needle in a haystack,” as reported by Interesting Engineering on December 10. The new technology boasts high sensitivity, utilizing low-noise single-photon detectors, making it extremely useful for underwater sensing activities such as ocean surveys, oil spill detection, and deep-sea resource exploration.
Single-photon Raman lidar system. (Photo: Xiamen University).
The device, developed by researcher Mingjia Shangguan and colleagues, is notably compact, consumes low power, and can operate at depths of 1,000 meters below sea level. It is sensitive enough to analyze the thickness of oil spills from as far away as 12 meters, using just one microjoule laser pulses. According to Shangguan, distinguishing material in the water and detecting their distribution characteristics in the ocean is crucial for marine environmental monitoring and scientific research. For instance, remote oil sensors help monitor leaks in underwater oil pipelines.
Traditional lidar systems are often used on ships, aircraft, or satellites and can scan the ocean on a large scale. However, their detection capabilities at great depths are limited, especially under rough sea conditions. In contrast, the Raman lidar system can analyze underwater environments at various depths without being affected by sea conditions. The Raman lidar operates by sending green laser light pulses into the water, where it interacts with materials like oil. This interaction generates an inelastic Raman signal that can be used to identify different substances. By measuring the intensity of the Raman signal at specific wavelengths, the lidar can provide information about the oil composition in the water.
The new lidar system from China measures 40 cm in length and has a diameter of 20 cm, allowing it to operate effectively at a depth of 1,000 meters. To enhance sensitivity, the research team has integrated single-photon detection capabilities into the underwater Raman lidar system. “Placing the Raman lidar system on automated or remotely controlled vehicles will help monitor leaks or be used for resource exploration and coral reef detection,” Shangguan stated.
Given its ability to capture high-resolution laser images of small underwater targets, it has potential applications in underwater archaeology, infrastructure inspection, and military operations such as reconnaissance and submarine detection. The team’s next plan is to develop underwater Raman lidar using shorter wavelength lasers, such as blue lasers, and to integrate them onto automated vehicles.
