Complete tunneling of light through a composite barrier consisting of multiple layers

The general conditions required for complete tunneling of light through surface impedance-matched barrier layers were investigated. By analogy with the effective barrier length defined by Kim [Phys. Rev. E 70, 047603 (2004)], we define the extended effective barrier length and show that complete tunneling occurs when the extended effective barrier length becomes zero. The surface mode plays an important role in complete tunneling that arises from balancing field enhancement and decay. We need at least one interface which supports a local surface mode, and it is not necessary that every interface between adjacent barrier layers support a surface mode. Complete tunneling can still occur under arbitrary permutations of the order of the barrier layers. The effect of total barrier length on the angular dependence is also discussed.