Field-dependent performance parameters of a plasmonic structure: an analysis of penetration depth and propagation length

Abstract

In this paper, the prism-based Kretschmann configuration is used to examine the plasmonic structure in terms of angle of incidence. For p - and s -polarized monochromatic incident light, the field-dependent performance parameters, such as field enhancement, penetration depth (PD), and propagation length (PL) of the considered structure, are investigated. We discovered that field enhancement is highest at resonance angle, but PD and PL are not maximum/minimum at this angle. At the critical angle, PD is at its highest, while PL is at its lowest. At resonance angle, the fields at the metal–sample interface are at their peak. By increasing the angle of incidence beyond the critical angle, PD in the sample decreases, while PL at the metal–sample interface increases. The PD and PL are same for any type of field ℜ ( H z ) , ℜ ( E x ) , ℜ ( E y ) , n o r m H = | H z | , | E x | , | E y | , and n o r m E = | E x | 2 + | E y | 2 . At resonance angles, the PD and PL are ∼ 0.190 µ m and ∼ 3.183 µ m , respectively. From the perspective of field distribution, this thorough analysis is expected to give a new paradigm for analyzing plasmonic structure with respect to angle of incidence.