Enhancement of evanescent waves in waveguides using uniaxially anisotropic metamaterials with an arbitrary angle between the optical axis and the interface

摘要

The enhancement of evanescent waves in multilayer planar waveguides with a uniaxially anisotropic metamaterials layer is investigated. Without loss of generality, we assume that the anisotropic metamaterials have an arbitrary angle between the optical axis and the interface, and then we derive the characteristic equations and the analytical expression of energy flux of this waveguides. It is found that the enhancement factor increases rapidly at first with increasing of the thickness of the metamaterials in the case when the optical axis is parallel to or normal to the interface, namely the angle is equal to 0 or nil. The enhancement factor eventually reaches its maximum when complete surface polaritons are established at the boundary between the metamaterials and the cladding [D.-K. Qing, G. Chen, Appl. Phy. Lett. 84(5), 669-671 (2004).]. Numerical results confirm our theoretical analysis.