7 papers
Subwavelength exceptional points in dispersive resonator arrays
Konstantinos Alexopoulos
Exceptional points provide a mechanism for producing strong spectral sensitivity in non-Hermitian wave systems. For subwavelength resonators with highly dispersive material paramet…
Frequency sorting in graded dispersive resonator arrays via volume-interaction matrices
Konstantinos Alexopoulos
We study graded arrays of highly dispersive subwavelength resonators through their volume-potential matrix reduction. The reduction gives a finite-dimensional nonlinear resonance p…
Asymptotics-guided learning and symbolic regression for dispersive resonances
Konstantinos Alexopoulos, Josselin Garnier
We study resonance prediction in dispersive media, formulated as nonlinear spectral problems for volume integral operators. The main idea is to use asymptotic analysis not only as…
Reduced-order modeling for electromagnetic inverse problems: a layered medium benchmark
Konstantinos Alexopoulos, Josselin Garnier
We study reduced-order modeling for inverse problems in layered media, focusing on the recovery of impedance profiles from time-domain measurements. Using the Goupillaud structure,…
Non-singular hotspots between closely spaced high-index nanoparticles
Konstantinos Alexopoulos, Bryn Davies, Pierre Millien
We study the concentration of the field between two nearly touching high-index dielectric resonators in three dimensions. The model is a scalar Helmholtz transmission problem in th…
Topological interface modes in systems with damping
Konstantinos Alexopoulos, Bryn Davies, Erik Orvehed Hiltunen
We extend the theory of topological localised interface modes to systems with damping. The spectral problem is formulated as a root-finding problem for the interface impedance func…
Topologically protected modes in dispersive materials: the case of undamped systems
Konstantinos Alexopoulos, Bryn Davies
This work extends the theory of topological protection to dispersive systems. This theory has emerged from the field of topological insulators and has been established for continuu…