Finding natural resources in the deep sea by laser
Localizing mineral resources on the sea floor has so far been associated with very high costs. A new laser-based analysis system to examine soil samples in the deep sea has passed initial practical tests.
The novel system is developed in the project Robust funded by the European Union, by the Laser Zentrum Hannover (LZH), Germany, in cooperation with eight partners. The system for laser-induced breakdown spectroscopy (LIBS) allows examining material samples for their atomic composition almost non-destructively. The LIBS system developed by the LZH successfully withstood a pressure of 400 bar in practical tests in the deep sea. Lasers, controls and software worked flawlessly. The experiments were carried out during a research trip in the Pacific on the research ship Sonne of the Federal Ministry of Education and Research. On the ROV Kiel 6000 diving robot from the Geomar Helmholtz Center for Ocean Research Kiel, Germany, the LIBS system dived to the bottom of the sea.
Further, the LIBS system was able to detect copper and zinc in real samples of massive sulfide at up to 500 bar. The measurements under deep sea conditions took place at the company Nautilus in Buxtehude, Germany. During a research trip in the Baltic Sea on Geomar's Littorina research ship, the system was able to detect copper and zinc in the prepared samples even in moderately cloudy water, reliably. These are promising results for further experiments under real conditions in the deep sea.
A video showing the animation of possible application scenarios for the Robust technology is linked here.
LIBS is a non-contact and almost non-destructive method for the analysis of chemical elements in solid, liquid and gaseous form. The method is based on the generation and analysis of a laser-induced plasma. Here, a high-energy laser beam is focused on the sample. The energy level of the laser beam at the focal point is high enough to create a plasma. The plasma in turn emits element-specific radiation, measured with a spectroscope. The emission lines in the spectrum are assigned to chemical elements in the sample.
The project Robotic Subsea Exploration Technologies (Robust), grant number: 690416, is funded by the European Union within the scope of the program Horizon 2020.
The LZH is an independent, non-profit research institute, supported by the Niedersachsen Ministry of Economic Affairs, Employment, Transport and Digitalization and is dedicated to applied research in the field of photonics and laser technology. Founded in 1986, over 170 employees are now working for the LZH.