Adjusting the opening and closing of the bandgaps of plasma photonic crystals

Closing or opening the first two photonic bandgaps (PBGs) of plasma photonic crystals (PPCs) by adjusting the plasma parameters are studied. We first calculated the impedance of the band structure of one-dimensional PPCs and found that in the presence of plasma, the impedance under two certain frequencies can match that of the air. We have verified through simulation that when the two PBG frequencies and two impedance-matched frequencies are equal to each other, the two PBGs can be closed simultaneously under the same plasma density. On the other hand, a more common situation is that we need two plasma densities to, respectively, close the two PBGs located near different impedance-matched frequencies. At this point, by adjusting the plasma density, the PBGs can be closed in segments, that is, we can choose to close or open the corresponding PBGs at different plasma densities.