Broadening the photonic bandgap in adiabatic distributed-Bragg-reflectors

TL;DR

This paper demonstrates how adiabatic following principles from quantum systems can be applied to design distributed-Bragg-reflectors (DBRs) with broadened photonic bandgaps, enhancing their optical properties.

Contribution

It introduces a novel analogy between quantum adiabatic population transfer and light propagation in DBRs, leading to optimized designs with broader photonic bandgaps.

Findings

Broadened photonic bandgap observed in designed DBRs.

Adiabatic constraints achieved through optimal DBR configurations.

Suppressed sharp transmission resonances in the reflection spectrum.

Abstract

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 a broad class of systems exhibiting SU(2) symmetry. In the present work, we present an analogy of population transfer dynamics of two level system with that of light propagation in a classical one-dimensional photonic crystal, commonly known as distributed-Bragg-reflector (DBR).This formalism facilitates in adapting the idea of adiabatic following, more precisely the rapid adiabatic passage (RAP) which is usually encountered in a broad class of quantum-mechanical systems.We present two different DBR configurations in which the adiabatic constraints are obeyed along the DBR length by virtue of optimum design. The reflection spectrum for both the configurations exhibit broadening of photonic bandgap (PBG) in addition to a varying degree of suppression of sharp transmission resonances. The inter modal coupling between counter-propagating modes as well as their phase-mismatch, for both the DBR configuration, exhibits a longitudinal variation which is usually observed in Allen-Eberly scheme of adiabatic population transfer in two-level atomic systems.