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

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 a two-level atomic 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 a chirped DBR configuration in which the adiabatic constraints are satisfied by virtue of optimally chirping the DBR. The reflection spectrum of the configuration exhibit broadening of photonic bandgap (PBG) in addition to a varying degree of suppression of sharp reflection peaks in the transmission band. The intermodal coupling between counter-propagating modes as well as their phase-mismatch, for the DBR configuration, exhibits a longitudinal variation which is usually observed in ‘Allen-Eberly’ scheme of adiabatic population transfer in two-level atomic systems.

Strategically constructed high-reflectivity multiple-stack distributed Bragg reflectors for efficient GaN-based flip-chip mini-LEDs

“…Based on one-dimensional photonic crystal structure, the DBRs are constructed by stacking two materials with different refractive indices. Owing to thin-film interference effect, the high reflection features of DBRs are closely related with photonic bandgap (PBG) similar to electronic band gap in semiconductors [27][28][29]. The light at specific wavelengths within PBG cannot propagate in DBRs, and these wavelengths determine reflective bandwidth of DBRs.…”

Особенности Поглощения Света В Чирпированных Одномерных Фотонных Кристаллах

“…Интерес к исследованию чирпированных ФК обусловлен также следующим обстоятельством. В чирпированных ФК наблюдается уширение фотонной запрещенной зоны (ФЗЗ) [15][16][17][18], в них возможна многомодовая лазерная генерация и лазерная генерация с перестра-иваемой в широких пределах длиной волны генерации [19,20], а также так называемое всенаправленное отражение (omnidirectional reflection) [20,21]: в определенном интервале длин волн всенаправленные отражатели полностью отражают свет с любой поляризацией и при любом угле падения. Эти свойства имеют важные практические применения, в частности в волоконнооптической связи, лазерах и т. д.…”

Peculiarities of light absorption in chirped one-dimensional photonic crystals

“…Interest in the study of chirped PCs is also due to the following circumstance. In chirped PCs, the photonic band gap (PBG) is observed [15][16][17][18], multimode laser generation is possible in them and lasing with a broadly tunable lasing wavelength [19,20], as well as the so-called omnidirectional reflection [20,21]: in a certain wavelength range, omnidirectional reflectors completely reflect light from any polarization and at any angle of incidence. These properties have important practical applications, in particular in fiber optic communications, lasers, etc.…”