Meta material has been demonstrated and applied in fabricating novel structures such as super lens, invisible cloaking and perfect absorber. The existence of a meta material layer in a stack consists of positive index material can result in a zero refractive index stack, which is also interesting in both physics and technology points of view . The stacking of negative index material and positive index material, where the impedances of negative index slab and positive index slab are matched, was manpulated so that the favorable outcome will be a zero equivalent index material with equivalent in pedance different from zero. The reflection coefficient was zero at 90 degree incident angle, hence no reflection, and the calculated transnmission is unity. Sinmulation demonstrates that there is no phase change and the wave propagates smoothly through the stack and the interfaces between slabs.Another kind of perfect absorber is also proposed by composing the 3-slab structure into the diffraction mulislits. Simulation show there are no back -scattering wave and transmitted wave.
