Abstract:The laser induced breakdown spectroscopy (LIBS) is an element analysis technique with the advantages of real time detection, simultaneous multi-element identification, and in-situ and stand-off capacities. To evaluate its potential of ocean applications, in this paper, the time resolved laser-induced breakdown spectroscopy for calcium concentration detection in water is investigated. With the optimum experimental parameters, the plasma emission lifetime is determined to be about 500 ns with 532 nm laser excitation, and 1000 ns with 1064 nm laser excitation. The lowest detection concentration of 50 ppm is achieved for calcium detection in CaCl2 water solution using the 532 nm LIBS. Even better detection sensitivity is achieved using the 1064 nm LIBS, and the resulted lowest detection concentration of calcium is 25 ppm. The results suggest that it is feasible to develop LIBS as an on-line sensor for metal element monitoring in the sea.