Sensitivities of TE-polarized electromagnetic fields to shape changes in diffraction gratings

This paper presents a technique to compute the derivatives of diffraction efficiencies of optical gratings with respect to changes to their geometric parameters. The method uses adjoint equations to compute the shape derivatives efficiently. This general method is developed for the case of TE polarized fields in planar diffraction and is implemented using a coupled-wave numerical technique. Possible applications of this method are in the solution of several inverse scattering problems arising in semiconductor manufacturing.