Researchers have developed a multifunctional frequency modulated continuous wave (FMCW) LiDAR that can perform high-precision 3D imaging and simultaneously measure multiple physical parameters, including temperature, gas concentrations, and liquid density. This innovation, published in Light: Science & Applications, addresses the growing need for integrated sensing in autonomous vehicles and spacecraft.
Traditional FMCW LiDAR systems provide accurate 3D imaging but lack the ability to detect internal battery states or environmental conditions. With the rise of electric vehicles, battery safety has become a critical concern, as thermal runaway poses significant risks. Early warning requires monitoring parameters such as temperature, electrolyte density, and characteristic gases like C2H2, CO2, and CH4. Currently, separate systems handle imaging and sensing, leading to complexity, high costs, and integration challenges. The new LiDAR combines these functions into a single device, offering a streamlined solution.
The system works by detecting echo signals from both free space and optical fiber. This dual approach enables 3D imaging of objects while also performing optical frequency domain reflectometry (OFDR) for sensing. OFDR uses the same linearly modulated light source as FMCW, allowing high spatial resolution and large dynamic range for measuring strain, temperature, pressure, and gas concentration. In proof-of-concept experiments, the team imaged a plastic plate with a "HIT" symbol at a distance of 30 meters, with adjustable resolution from 0.3 cm to 1.2 cm. They also measured the density and temperature of a sulfuric acid solution (representing battery electrolyte) with accuracies of 3×10⁻⁵ g/mL and 0.5 °C, respectively. Gas concentrations were detected with limits of 0.07 ppm for C2H2, 48 ppm for CO2, and 0.56 ppm for CH4.
Professor Yongkang Dong from Harbin Institute of Technology, who led the study, explained the operational principle: "In the LiDAR module, the distance of the target can be calculated from the optical path difference between the collimator reflection peak and the target reflection peak. The reflection spectra of the FBG, FP, and MPC can be demodulated from their reflection peaks in spatial domain by inverse Fourier transform." This allows simultaneous measurement of multiple parameters with a single demodulator.
The proposed multifunctional LiDAR holds significant potential for improving the safety of new energy vehicles by enabling integrated monitoring of both the driving environment and battery health. It could also find applications in spacecraft, where compact and efficient sensing systems are essential. The researchers believe this technology provides a new integrated solution to enhance the safety and efficiency of autonomous systems.
