Subwavelength nonlinear plasmonic nanowire

We investigate numerically, by means of the finite-difference time-domain method, the propagation characteristics of surface plasmon-polariton (SPP) modes excited in an optical nanowire consisting of a chain of Ag spheres embedded in dielectric shells made of materials with optical Kerr nonlinearity. It is demonstrated that, in the linear limit, the nanowire supports two SPP modes, a transverse and a longitudinal one, separated by Deltalambda = 20 nm. Furthermore, the dependence of the transmission characteristics of these SPP modes, on both the pulse peak power and Kerr coefficient of the dielectric shell, is investigated. Nonlinear optical phenomena, such as power dependence of mode frequency, switching, or optical limiting, are observed and discussed.