Double slit difraction of three interfering beams

In this paper we consider a 2D diffraction problem in which three plane wav es of different inclinations are diffracted through two infinite slits of e qual width. An analytical solution is suggested and numerical calculations are made with the Rayleigh-Sommerfeld diffraction formula in the Fresnel ap proximation. The beams were taken to be monochromatic and mutually coherent . The width of the slits and the angles between incident beams was taken so , that the field amplitude at the edges of slits was equal to zero. This ca se has similar geometry, and has closed analytical solution in terms of the Fresnel integrals. This is presented for the first time, to our knowledge.