Observation of large photonic band gaps and defect modes in one-dimensional networked waveguides

The photonic band structures and transmission spectra of serial loop structures (SLSs), made of loops pasted together with segments of finite length, are investigated experimentally and theoretically. These monomode structures, composed of one-dimensional dielectric materials, may exhibit large stop bands where the propagation of electromagnetic waves is forbidden. The width of these band gaps depends on the geometrical and compositional parameters of the structure and may be drastically increased in a tandem geometry made up of several successive SLSs which differ in their physical characteristics. These SLSs may have potential applications as ultrawide-band filters.