Circular quantum wire symmetrically loaded with a graphene strip as the plasmonic micro/nano laser: threshold conditions analysis.

We study, apparently for the first time, the threshold conditions for the time-harmonic natural modes of the micro-to-nanosize plasmonic laser shaped as a circular quantum wire with a flat graphene strip, placed symmetrically inside it, in the H-polarization case. We suppose that the quantum wire is made of a nonmagnetic gain material, characterized with the aid of the "active" imaginary part of the complex refractive index. The emergence of lasers integrating plasmonic effects marks a significant trend in contemporary photonics.

Singular integral equations analysis of THz wave scattering by an infinite graphene strip grating embedded into a grounded dielectric slab.

We consider the scattering and absorption of a plane -polarized THz wave by an infinite periodic graphene strip grating embedded into a grounded dielectric slab. The problem is reduced to the dual series equations, which, in turn, are reduced to the singular integral equation with additional conditions. The numerical method of the solution is based on the Nystrom-type algorithm and has guaranteed convergence.