Resonant tunnelling properties of photonic crystals containing mu-negative materials

We study the transmission properties of photonic crystals consisting of mu-negative material (MNM) and positive-index material (PIM) using transfer matrix methods. The results show that there exists a transmission band inside a single-negative gap in the proposed structure. The central frequency of the transmission band is sensitive to the thickness of the positive-index layers, while the width of the transmission band is only dependent on the thickness of the MNM layers, which makes the frequency and width of the transmission band controllable. The tunnelling mode is localized strongly inside the PIM layers, and the electric field is enhanced exponentially with the increase in the thickness of the mu-negative layers. Transmittance can be increased by decreasing the thickness of the MNM layers.