LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Shore-based lidar for monitoring coastal sea water areas

A shore-based lidar, which plays a vital role in the creation of continuous express monitoring of coastal sea water areas, is described. The results of testing in the region of the Blue Bay (Black Sea, near Gelendzhik) are reported. Echo-signal spectra were recorded by exciting water by light at wavelengths 532, 355 and 266 nm (second, third and fourth harmonics of a Nd:YAG laser). The dependence of the echo signal (Raman scattering of light by water molecules) on the sensing range is studied. The obtained results are in good agreement with the theory of remote laser sensing developed in this work for large sensing angles, in which the wind waves play a key role. A sensing range of 100 m was achieved using 532-nm, 10-ns laser pulses at a pulse repetition rate of 10 Hz and the pulse energy of 10 mJ. The possibility of increasing the sensing range to 0.5–1 km is shown.