Optical superlattices for modulation and deflection of light

A novel kind of doubly resonant light scattering involving the Floquet–Bloch waves of a fine-period stratified structure is discussed. These waves can be Bragg scattered by a weak coarse-period superlattice provided a certain Bragg-like resonant condition is satisfied. Included among the unique properties of this kind of scattering are wavelength selective wide-angle beam deflection by acoustic waves in the 10 MHz–1 GHz range, the ability to enhance or impair the efficiency of Bragg reflection by a conventional fine-period grating, and, in one particular case, very wide-band modulation of light. Coupled-wave equations describing this interaction are solved for a variety of different geometries, and some potential applications proposed.