Propagation of electromagnetic waves through liquid crystals with defect-based interfaces, resembling a metamaterial waveguide.

We present a theoretical study of defect modes for electromagnetic wave propagation in cholesteric liquid crystal (CLC)-based trilayer structures with metallic inclusions. The system, composed of a crown-glass substrate, a metallic layer, and a CLC slab containing a jump defect, is modeled through Maxwell's equations reformulated in Marcuvitz–Schwinger form and solved numerically under appropriate boundary conditions. Effective dielectric properties are obtained via an anisotropic extension of the Maxwell–Garnett approach. Dispersion relations reveal the emergence of localized modes associated with defect-induced resonances, characterized by distinct real and imaginary wavevector components. Field distributions for the electric, magnetic, and Poynting vector show enhanced confinement near the defect region, with strong amplification at resonance frequencies and clear evidence of energy trapping, we also observed the existence of a region of negative group velocity in the dispersion relation, such behavior resembles metamaterials. The comparison between single-period and multi-period CLC slabs demonstrates that increasing periodicity reinforces localization and mode stability. These results highlight the role of structural defects in tailoring light propagation through anisotropic composite waveguides and open perspectives for tunable photonic devices based on liquid crystals.