Multichannel filtering properties of photonic crystals containing single-negative materials

The multichannel filtering properties have been investigated by means of the transfer matrix method in photonic crystals containing two kinds of single-negative materials. Two sets of filtering channels appear simultaneously in the zero effective phase gaps. One is omnidirectional for TE polarization but angle-sensitive for TM polarization, while the other is angle-sensitive for TE polarization but omnidirectional for TM polarization. The resonance modes for different channels can be independently tuned. This structure provides an efficient way to fabricate omnidirectional multichannel filters with independently tunable polarization channels.