Vol. 35, Issue 2, pp. 201-207
Keywords
thin films, multilayers, filters, bandgaps, 1D photonic crystals
Abstract
The paper is concerned with one-dimensional multilayers that exhibit multiple bands of omnidirectional reflection, which means complete reflection regardless of incidence angle and polarization. The typical quarter-wave constraint is replaced by the stipulation that a pair of adjacent layers should have a total optical thickness of one half of wavelength. Simple approximate analytic expressions are derived for the multiple bandgaps of the half-wave periodic structures.