LOSSY MULTISTEP LAMELLAR GRATINGS IN CONICAL DIFFRACTION MOUNTINGS - AN EXACT EIGENFUNCTION SOLUTION

The method of exact eigenfunctions has proven to be effective for the scalar grating problem. This makes it worthwhile to apply the method t o the vectorial grating problem, also referred to as the problem of co nical diffraction. The approach to exact eigenfunctions considered her e relies on a refinement of approximate eigenvalues. For complicated g ratings in particular, this technique reduces the numerical effort req uired to compute the vectorial eigenfunctions. Metallic and dielectric cavity-type structures as well as other structures with strong resona nces are studied. Good convergence properties have been observed for a wide range of parameter values. The vectorial treatment of the case o f general incidence provides new theoretical results for the color-sep aration problem.