Detecting Submerged Objects Based On Stimulated Brillouin Scattering

Detecting method of submarine object was proposed in single SBS cell within focusing geometry.Basic coupled-wave equations of SBS were built based on the Maxwell electromagnetic equations and the material energy equations, and then physical models of phase conjugate mirror for numerical simulation were put up. Using an implicit finite differencing in time and a down-wind differencing scheme in space, the differencing form of coupled wave-equations was established. Then computer numerical simulations were given in the single SBS cell within focusing geometry with the FORTRAN language.By numerical simulation, the influences of medium sea water parameters, focusing parameters and the pump parameters on SBS were given. The changing rule of energy reflection, peak power magnification, pulse with compression ratio and build-time of SBS varying with focusing parameters and pump parameters in single SBS cell with focusing geometry were analyzed.Choosing experimental parameter according to the theoretical calculation, Detecting results of submarine object by SBS were given in the laboratory. The experimental result indicated as follows: within 200cm scope, the most maximal experimental error is less than 10cm, and the error is decided by the pulse width of laser, the photo-electric detector speed and the oscilloscope sampling rate. Experimental investigations of energy reflection varying with focusing parameters, pump parameters and medium parameters were conducted. Experimental results are agreeable with theoretical calculations in the changing trend.