Analysis of interface mode localization in disordered photonic crystal structure

A disordered photonic crystal (D-PhC) structure is analyzed to study the interface mode localization characteristics. The design comprises a bilayer-disordered PhC structure, where layers are arranged in Thue-Morse sequence (TMS). The impact of local symmetric substructures on eigenstates coupling is also considered over a wider wavelength range. The mode hybridization study is carried out for varying refractive index contrast values of TMS structures at an operating wavelength of 550, 632.8, and 750 nm, respectively. The dispersion analysis confirms the localization of bulk guided, and edge-guided modes for different incidence angles at the structural local resonators. Further, increasing the RI contrast value leads to generation of hybrid interface modes of very high electric field intensity. Thus, showing its potential applications in both sensing and light guiding applications. Moreover, because of the higher surface electric field intensity this structure can also be used for fluorescence-based detection and surface-enhanced Raman spectroscopy as well.