STABILITY ISSUES IN VECTOR ELECTRIC-FIELD PROPAGATION

We demonstrate that although standard paraxial and wide-angle vector f ield propagation techniques lead to divergences for sufficiently small grid-point spacings and large refractive index differences, stability may he restored through either certain Pade approximants to the propa gation operator or suitable boundary conditions. We also introduce a n ovel alternating directional implicit method applicable to less diverg ent discretizations of the vector wave equation.