Cascaded coupling: Realization and application to spectral maneuvering

Garg, Ruchi; Thyagarajan, K.

doi:10.1016/j.yofte.2012.12.005

Cited by 8 publications

(2 citation statements)

References 13 publications

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“…In case of DBR, the coupling between a forward propagating mode (A p ≡ A i ) and a backward propagating mode (A q ≡ A r ) is of interest. In absence of any other intermodal interactions, the forward-backward mode coupling (assuming m = 1) would be governed by [24][25][26],…”

Section: Adiabatic-following In Dbrmentioning

confidence: 99%

Broadening the photonic bandgap in adiabatic distributed-Bragg-reflectors

Sharma,

Mondal,

Das

2021

Preprint

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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 intermodal 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.

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Section: Adiabatic-following In Dbrmentioning

confidence: 99%

Broadening the photonic bandgap in adiabatic distributed-Bragg-reflectors

Sharma,

Mondal,

Das

2021

Preprint

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“…On the other hand, the respective reflection response for the spectral region where the localized cavity modes are excited mimics the near-zero reflection characteristics of the smaller-sized blocks. This essentially means, that the pyramid arrangement of the individual microantenna blocks facilitates an efficient cascaded coupling[53] of EM energy to each individual microantenna blocks. In this manner, the entire micropyramid acts like an efficient broadband micro-resonator, causing the trapped EM energy to get absorbed by the SiC material over a broad frequency range.…”

mentioning

confidence: 99%

Broadband Near-Unidirectional Absorption Enabled by Phonon-Polariton Resonances in SiC Micropyramid Arrays

Devarapu

Foteinopoulou

2017

Phys. Rev. Applied

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Inspired by moth eyes, nature's most powerful antireflex, we present a sub-wavelength SiC micropyramid design, which operates in the Reststrahlen band of SiC, namely the spectral band of strong phonon-photon coupling in the SiC material. While within this band SiC repels EM waves, we observe here a broad low-reflectivity window with unique attributes, with distinct characteristics different from typical dielectric moth-eye-like structures. To be specific, while the latter systems are entirely symmetric, the reflection response of our SiC micropyramid system can be highly asymmetric. In particular, the SiC micropyramid system can be near-reflectionless for light impinging from the tip side of the micropyramids and exhibits more than 90% reflection for light impinging from the base side of the micropyramids, over a broad wavelength range in the SiC Reststrahlen band. This strongly asymmetric reflection response emanates from the cascaded coupling of vortex-like cavity modes at each of the SiC blocks comprising the micropyramids and translates into a strongly uni-directional absorber response. We discuss how, by virtue of Kirchhoff's law, this strongly uni-directional superabsorber behavior implies a strongly uni-directional emission profile that is important for one-way infrared sources and passive radiative-cooling systems.

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