Hyperspectral Raman LiDAR Advances Microplastic Detection

Microplastics are making headlines—and for good reason. These tiny plastic particles have infiltrated our oceans, soils, food, and even the air we breathe. Because they don’t break down easily, they pose a long-term threat to ecosystems and human health. Microplastics can also carry harmful chemicals, potentially disrupting hormones and causing inflammation when ingested or inhaled. Monitoring and mitigating this pollution is a growing challenge, but researchers at the Institute for Laser Technology in Japan may have a powerful new solution: a hyperspectral Raman imaging LiDAR system designed for efficient, remote detection of plastic debris.

This system combines two advanced technologies: LiDAR, which measures distances using laser pulses, and Raman spectroscopy, which identifies materials by analyzing how they scatter light. While LiDAR excels at mapping objects, Raman spectroscopy determines what those objects are made of by detecting their unique molecular “fingerprints.” It works by shining a laser on a material and measuring the subtle shifts in the light’s wavelength caused by interactions with molecular bonds, revealing its chemical composition. By integrating these capabilities, researchers have developed a tool that can not only locate plastic debris but also identify its type—all from a distance.

The system uses a pulsed 532-nm green laser and a gated ICCD spectrometer to analyze plastics remotely. Unlike traditional lab-based methods, which are time-consuming and resource-intensive, this compact system is designed for efficient, real-time monitoring. “A drone equipped with our LiDAR sensor could be used to assess marine plastic debris on land or in the sea, paving the way for more targeted cleanup and prevention efforts,” said research team leader Toshihiro Somekawa. In tests, the system successfully identified polyethylene and polypropylene sheets from 6 meters away, achieving an impressive spatial resolution of 0.29 millimeters—precise enough to analyze even small plastic fragments.

What makes this system unique is its ability to capture both imaging and spectroscopic data simultaneously. This means it doesn’t just detect plastics—it also maps their spatial distribution, providing a clearer picture of pollution patterns. Looking ahead, researchers plan to adapt the technology for detecting microplastics in water, taking advantage of the laser’s ability to penetrate aquatic environments. By merging LiDAR’s precise mapping with Raman spectroscopy’s material identification, this system could transform how we monitor and combat marine plastic pollution. It’s a promising step toward more effective environmental protection.

See the full Optica article HERE