Perfect transmission and highly asymmetric light localization in photonic multilayers

General principles for the existence of perfect transmission resonances in photonic multilayer structures are formulated in terms of light interference described by recurrent Airy formulas. Mirror symmetry in the multilayer is shown to be a sufficient but not necessary condition for perfect transmission resonances. Asymmetric structures displaying perfect transmission in accordance with the proposed principles are demonstrated. A hybrid Fabry-Perot/photonic-crystal structure of the type (BA)^k(AB)^k(AABB)^m is proposed, combining perfect transmission and highly asymmetric electric field localization. Strength and asymmetry of localization can be controlled independently, to be of use in tailoring non-reciprocal behavior of nonlinear all-optical diodes.