Analysis of the Bloch mode spectra of surface polaritonic crystals in the weak and strong coupling regimes: grating-enhanced transmission at oblique incidence and suppression of SPP radiative losses

Abstract

The Bloch mode spectrum of surface plasmon polaritons (SPPs) on a finite thickness metal film has been analyzed in the regimes of weak and strong coupling between SPP modes on the opposite film interfaces. The SPP mode dispersion and associated field distributions have been studied. The results have been applied to the description of the light transmission through thick and thin periodically structured metal films at oblique incidence. In contrast to normal incidence, all SPP Bloch modes on a grating structure participate in the resonant photon tunnelling leading to the transmission enhancement. However, at the angle of incidence corresponding to the crossing of different symmetry film SPP Bloch modes, the far-field transmission is suppressed despite the enhanced near-field transmission. The combined SPP mode consisting of the two film SPPs having different symmetries that is achieved at the crossing frequency exhibits no radiative losses on a structured surface.

Surface-plasmon-enhanced light transmission through planar metallic films

“…This agrees with the suggestion of enhanced transmission being the result of resonant SP-assisted light tunneling through metal films [10,11]. The resultant spectra are subject to the strength of each mode.…”

“…It is now well accepted that the excitation of surface plasmons (SPs) plays an important role in the extraordinary transmission through sub-wavelength hole arrays, however the fact that the SPs and the sub-wavelength features that generate them co-exist on the same film (or films) tends to confound the analysis somewhat. As a result, many analytical models [6,7,8,9,10,11,12] have been proposed to understand their physical origins.…”

“…Subsequently, some authors have suggested that continuous metallic films can also exhibit enhanced transmission provided they are periodically modulated [10,11,12,14]. Extending this further, it is worthwhile to also consider the transmission characteristics of completely planar metal films (no modulation whatsoever) with some independent means for SP excitation.…”

Surface-Plasmon-Polariton Assisted Diffraction in Periodic Subwavelength Holes of Metal Films with Reduced Interplane Coupling

“…The dispersion curves for both polarizations are displayed in to Refs. [8,18], we believe that strong interplane coupling would hinder the observation of the splitting behavior under TE polarization. The strong coupling could be the reason why in the previous work no splitting in the TE polarization has been reported.…”

Hybrid Plasmon-Mediated Optical Transmission in Separated Metallic Layers with Nanostructures

“…Surface plasmon-polaritons (SPPs) in a nanostructured metallic single layer have become a vital research topic due to the fact that they provide not only extraordinary optical properties with or without apertures, yielding novel applications such as biosensors, integrated waveguide circuits, and others [1][2][3][4][5][6][7][8][9][10], but also performance improvement of optoelectronic devices which use this type of layer [11][12][13]. Beyond SPPs in a metallic single layer, SPPs in metallic multiple layers have attracted attention recently owing to interest in their novel optical responses, such as negative refractive index, extreme light focusing, optoelectronic circuitry [14][15][16][17][18][19][20], and expectation that they can improve the performance of advanced optoelectronics devices [11,[21][22][23][24][25].…”