Enhancing the efficiency of slit-coupling to surface-plasmon-polaritons via dispersion engineering

Abstract

Abstract:We describe a simple method for enhancing the efficiency of coupling from a free-space transverse-magnetic (TM) plane-wave mode into a surface-plasmon-polariton (SPP) mode. The coupling structure consists a metal film with a dielectric-filled slit and a planar, dielectric layer on the slit-exit side of the metal film. By varying the dielectric layer thickness, the wavevector of the SPP mode on the metal surface can be tuned to match the wavevector magnitude of the modes emanating from the slit exit, enabling high-efficiency radiation coupling into the SPP mode at the slit exit. An optimal dielectric layer thickness 100 nm yields a visible-frequency SPP coupling efficiency 4 times greater than the SPP coupling efficiency without the dielectric layer. Commensurate coupling enhancement is observed spanning the regime 400 nm ≤ λ 0 ≤ 700 nm. We map the dependence of the SPP coupling efficiency on the slit width, the dielectric-layer thickness, and the incident wavelength to fully characterize this SPP coupling methodology.

Polarization-dependent extraordinary optical transmission from upconversion nanoparticles

“…The free-space light and SP resonance mode coupling efficiency 30,54 often affects the EOT intensities. Both experimental and FDTD-calculated results indicate an enhanced red light relative to the green light as expected.…”

Plasmonic Micro Lens for Extraordinary Transmission of Broadband Light

“…al. 34. It is observed that the absolute contribution of the intensity due to surface plasmons remains almost the same in both the nanohole and microhole apertures.…”

Highly Efficient Excitation of Surface Plasmon Polaritons Under Asymmetric Dielectric Surroundings

“…Therefore, how to elevate or what factors will affect the launching efficiency of SPP is inevitably a very important issue. Recently, many SPP-based metallic nanostructures with different designs have been proposed and studied in both theory [1][2][3][4][5] and experiment [6][7][8][9] and attempted to solve this problem. However, these complex structures are usually very hard to fabricate in practice.…”

“…Thus, how to effectively and easily improve the intensity and efficiency of SPP becomes much more needed. On the other hand, the surrounding dielectric medium of subwavelength apertures is also a significant factor to influence the SPP excitation [3,4], but less attention has been paid to either this parameter or the electromagnetic behavior generated in structures with this parameter, such as interference, which would affect the calculated accuracy.…”

“…A plane wave illuminates the structure in the Y-axis direction from below with the wavelength of λ 0 =1 μm. The distances H 1 , H 2 , and H 3 are taken from Ref 3. …”