Geometric representation of adiabatic distributed-Bragg-reflectors and broadening the photonic bandgap

Adiabatic following has been an widely-employed technique for achieving near-complete population transfer in a `two-level' quantum mechanical system. The theoretical basis, however, could be generalized to broad class of systems exhibiting SU(2) symmetry. In the present work, we analogy dynamics two level atomic system with that light propagation classical `one-dimensional' photonic crystal, commonly known as distributed-Bragg-reflector (DBR). This formalism facilitates adapting idea adiabatic following, more precisely rapid passage (RAP) which is usually encountered quantum-mechanical systems. We chirped DBR configuration constraints are satisfied by virtue optimally chirping DBR. reflection spectrum exhibit broadening bandgap (PBG) addition varying degree suppression sharp peaks transmission band. intermodal coupling between counter-propagating modes well their phase-mismatch, configuration, exhibits longitudinal variation observed `Allen-Eberly' scheme two-level