Effect of retardation on the frequency and linewidth of plasma resonances in a two-dimensional disk of electron gas

We theoretically analyze dominant plasma modes in a two-dimensional disk of electron gas by calculating the absorption an incident electromagnetic wave. The problem is solved self-consistent approximation, taking into account retardation effects. use Drude model to describe conductivity system. spectrum exhibits series peaks corresponding excitation waves. position and linewidth designating, respectively, frequency damping rate modes. estimate influence effects on fundamental (dipole) axisymmetric (quadrupole) both numerically analytically. find net be dependent not only sum radiative collisional decays but also their intermixture, even for small retardation. show that can noticeably less than determined collisions alone.