Hybrid representations of asymmetrically excited surface plasmon self-interference at a planar dielectric/metal interface.

We introduce a hybrid representation to describe asymmetrically excited surface plasmon (SP) self-interference at a planar dielectric/metal interface. The hybrid representation combines a ray model, angular spectrum representation, near-field spatial frequency analysis, and parameter characterization to investigate the incidence coupling and spatial resolution degradation of the SP self-interference. We also propose SP numerical aperture for self-interference virtual probe imaging.

Paraxial models for the surface plasmon self- interference at off-axis excitation.

The surface plasmon self-interference excited by a strongly focused, linearly polarized vortex beam at off-axis illumination in a paraxial regime is analytically studied. The off-axis excitation is investigated using a geometrical model. The combination of an angular spectrum representation and homogeneous transformation is applied to derive the integral expressions of the surface plasmon polariton fields for off-axis directions both parallel and perpendicular to polarization plane, and an off-axis convergence angle is used to compute the integral.

Theoretical analysis of obliquely excited surface plasmon self-interference.

We present the theoretical analysis of surface plasmon polaritons induced by a tightly focused light beam at oblique incidence. Firstly, we propose a geometrical model to explain the evolution of SPPs effect as light deviating from normal incidence, and introduce a concept of critical oblique angle (θ(co)) which is one of the key factors affecting the stability, efficiency and lateral resolution of SPPs. Secondly, the integral expressions for the transmitted SPP field excited by a linearly polarized vortex beam are derived, using angular spectrum representation and rotation matrix trans-formation, for the oblique directions as parallel and perpendicular to polarization plane.