Omnidirectional high absorption based on an asymmetric photonic crystal composed of negative-index material and positive-index material

摘要

The absorption enhancement of photonic crystals composed of negative-index material and positive-index material is investigated in this article. It is found that whole absorption of an electromagnetic wave with weak dependence on the incident angle can be achieved in an asymmetric structure by adjusting materials and parameters. Furthermore, with the incident angle increasing to 80°, we demonstrate that the absorption for both polarizations remains over 80%. Finally, the influence of the damping factor of the Drude model is studied, and a conclusion is drawn that says the absorption is invariant with the damping factor when the ratio between the damping factor and the electronic or magnetic plasma frequency is smaller than 10-4.