Diffraction of light by superposed parallel supersonic waves, being harmonics of the same fundamental. Solution of the system of difference-differential equations for the amplitudes
Starting from the general system of difference-differential equations for the amplitudes of the diffracted beams of light, given by Mertens, and using the method of Kuliasko, Mertens and Leroy for the diffraction of light by one supersonic wave, it is possible to reduce the solution of the system of difference-differential equations, to the solution of a partial differential equation. In this way it is possible to calculate the intensities of the ordern and −n, as a series expansion in ρ. Here we only considered terms up to ρ2. It was also possible to verify the general symmetry properties for the intensities studied by Leroy and Mertens.