Photonic band gap structures in 2D tunable magnetic photonic crystals

The photonic band structures in 2D tunable hexagonal magnetic photonic crystals were investigated on the basis of plane wave expansion method. It was found that the photonic band gaps tended to exist in the magnetic photonic crystals, and magnetic permeability affected the photonic band gaps strongly. The width of two absolute band gaps was reduced gradually, then they vanished when magnetic permeability increased from 1.0 to 5.0 in photonic crystals with magnetic scatterers surrounded by air. However, as magnetic permeability continued to increase, an absolute band gap could appear in the lower frequency, and gap-mid-gap ratio increased and the optimal filling ratio changed tightly. Analogously, an absolute band gap also appeared in the lower frequency in photonic crystals with air scatterers surrounded by magnetic material. Further, the results revealed that the characteristic in photonic crystals with dielectric scatterers surrounded by magnetic material is similar to that in photonic crystals with magnetic scatterers surrounded by air.