Interferential polychromatic filters

The reflection properties of one-dimensional generalized Cantor-like multilayer (GCLM) are investigated numerically in the visible range. Strong correlation between the stack geometry and the properties of the optical reflection spectra is found, namely spectral scalability and sequential splitting. The construction of multilayer systems according to the definite Cantor distribution brings improvements to the reflection properties. In particular, the widening of the band gap and the thin peak appearance in the reflection spectra whose number increases with the division number in the (GCLM). Optical properties of (GCLM) inserted between two periodic stacks are numerically investigated. We chose SiO₂(L) and TiO₂ (H) as two elementary layers. The study configuration is H(LH)⁵[GCLM]^PH(LH)⁵ which forms an effective interferential filter in the visible spectral range. We show that the number of resonator peaks is dependent on the repetition of the number P of the (GCLM). The best performances are obtained in particular for the symmetrical configurations of the (GCLM) and especially for P an odd number.Received: 10 July 2003, Published online: 30 January 2004PACS: 61.44.Br Quasicrystals - 42.70.Qs Photonic bandgap materials - 42.79.Ci Filters, zone plates, and polarizers