Rigorous vector theory for diffraction from gratings made of biaxial crystals

MARINA ELIZABETH INCHAUSSANDAGUE; DEPINE, RICARDO ANGEL

Journal of Modern Optics

Taylor & Francis

Lugar: London; Año: 1997 vol. 44 p. 1 - 27

We present a rigorous formalism to solve the problem of diffractionof light at a periodically corrugated boundary between an isotropicmedium(dielectric or metal with losses) and a biaxial crystal. The method applies togratings illuminated either from the isotropic or from the biaxial side by waveswith wave vectors inclined at an arbitrary angle with respect to the grooves andfor arbitrary orientations of the crystal optic axes. Using a nonorthogonalcurvilinear coordinate transformation that simpli? es the boundary conditionsat the grating interface and writing Maxwell? s equations for the covariantcomponents of the ? elds in the transformed frame, the problem can be reducedto the numerical solution of a system of ? rst order differential equations withconstant coef? cients. The application of the method is illustrated in two cases:(i) diffraction of s- and p-polarized waves at a sinusoidal boundary between atransparent dielectric and a biaxial crystal and (ii) excitation of surface plasmonsalong the corrugated interface between a metal and a biaxial crystal.