Development and sea trial validation of a deep-sea element sensor based on laser-induced breakdown spectroscopy

Abstract

As a real-time in situ elemental detection technology, Laser-Induced Breakdown Spectroscopy (LIBS) has been applied to the detection and exploration of marine environments and mineral resources. However, due to the influence of high pressure, there have been no reported LIBS detection results for solid samples at depths exceeding 4000 m on the seabed. This study developed a novel elemental chemical sensor system using high-pressure gas ventilation, creating a high-pressure gas environment on the seabed to avoid the influence of seawater on the LIBS results. In 2024, the elemental chemical sensor system was deployed on the Haixing 6000 remotely operated vehicle (ROV) for three deep-sea trials, achieving the world's first spectral line results for carbon steel samples on the seabed at 6000.8 m depth. The research also investigated the influence of delay time on spectral results at 6000.8 m depth. Comparative analysis revealed that the gas-ventilation method effectively extends plasma lifetime compared to direct solid detection in aqueous environments. The above results demonstrate that the elemental chemical sensor possesses the capability for in situ detection of solid samples in deep-sea environments, providing a novel and effective solution for submarine geochemical research and submarine mineral exploration.