Dynamic control of defective gap mode through defect location

TL;DR

This study develops a 1D model to analyze how defect location influences the dynamic control of defective gap modes in periodic systems, with implications for photonic and plasma applications.

Contribution

It introduces a model showing how defect location can be used to dynamically control the frequency and spatial properties of defective gap modes.

Findings

Conducting-mesh-induced DGM is well confined by spectral gaps.

Conducting-sleeve-induced DGM is less confined and more sensitive to defect location.

Defect location enables dynamic tuning of DGM in photonic and plasma systems.

Abstract

A 1D model is developed for defective gap mode (DGM) with two types of boundary conditions: conducting mesh and conducting sleeve. For a periodically modulated system without defect, the normalized width of spectral gaps equals to the modulation factor, which is consistent with previous studies. For a periodic system with local defects introduced by the boundary conditions, it shows that the conducting-mesh-induced DGM is always well confined by spectral gaps while the conducting-sleeve-induced DGM is not. The defect location can be a useful tool to dynamically control the frequency and spatial periodicity of DGM inside spectral gaps. This controllability can be applied to optical microcavities and waveguides in photonic crystals and the interaction between gap eigenmodes and energetic particles in fusion plasmas.