title: Photonic band structure and symmetry properties of electromagnetic modes in photonic crystals.
abstract: Within the Maxwell framework and using a transfer-matrix technique we have determined a general equation which governs the photonic band structure and the density of states of one-dimensional superlattices composed of two alternate layers characterized by different refractive indexes, which may take on positive as well as negative values. Besides the usual well-known results, we have found null-gap points for commensurate values of the optical path lengths of each layer. Furthermore, we have been able to characterize non-Bragg gaps that show up in frequency regions in which the average refractive index is null.
authors.affiliation: Instituto de Física, Universidade Federal de Alagoas, Maceió-AL, 57072-970, Brazil.
authors.forename: S B
authors.initials: SB
authors.lastname: Cavalcanti
authors.forename: M
authors.initials: M
authors.lastname: de Dios-Leyva
authors.forename: E
authors.initials: E
authors.lastname: Reyes-Gómez
authors.forename: L E
authors.initials: LE
authors.lastname: Oliveira