Omnidirectional transmission bands of one-dimensional metal-dielectric periodic structures

We show that a one-dimensional metal-dielectric (MD) periodic structure can possess an omnidirectional band for a p-polarized wave, owing to the compensation effect of power flow in the parallel direction in the metal. When the net power flow in the direction parallel to the MD interface is zero or very small compared to the total power flow in the direction perpendicular to the interface, a dispersionless band with (nearly) flat band edges in the projected band diagram will occur. We numerically and experimentally demonstrate an omnidirectional passband in an Ag-ZnS stack. Such an omnidirectional passband can be realized in a different wavelength region with a proper design. (C) 2008 Optical Society of America.