Dielectric-loaded surface plasmon polariton waveguides: Figures of merit and mode characterization by image and Fourier plane leakage microscopy

Abstract

International audienceWaveguiding of surface plasmon polaritons by dielectric-loaded metal structures is studied in detail by combining numerical simulations and leakage radiation microscopy. These types of waveguides are first numerically investigated using the effective index model and the differential method. We analyzed systematically the influence of the ridge width and thickness of the waveguide on the properties of the surface plasmon guided modes. In particular we investigated the confinement factor of the modes and their associated propagation lengths. These two parameters can be optimized by adjusting the thickness of the dielectric layer. Waveguides loaded with thick and thin dielectric ridges are then optically characterized by leakage radiation microscopy. The mode propagation distance is measured by direct-space imaging and the propagation constants are evaluated by Fourier imaging and analysis. Good agreements are found between theoretical and experimental data

Bloch oscillations in plasmonic waveguide arrays

“…For this purpose, we have fabricated arrays of evanescently coupled dielectric-loaded surface plasmon polariton waveguides (DLSPPWs) 18,19 by a sophisticated negative-tone gray-scale electron beam lithography process 20 . This process enables us to precisely control all geometrical sample parameters with high precision (see Methods).…”

Analysis of dielectric loaded surface plasmon waveguide structures: Transfer matrix method for plasmonic devices

“…For instance, in Ref. 12 (the wavelength is 780 nm, the dielectric stripe is SiO 2 with the refractive index of 1.45, and its thickness is 70 nm) the effective index of the SPPs mode is 1.15, and our TMM result gives 1.14. In another example, in Ref.…”

“…[2][3][4][5] Up to now, different kinds of SPP waveguides have been proposed, such as the hybrid plasmonic waveguide, 6,7 the channel plasmonic structures, 8 the gap SPPs waveguide, 9,10 and the dielectric loaded surface plasmon polaritons (DLSPP) waveguide. 11,12 The DLSPP waveguide demonstrates strong lateral confinement, low edge-scattering and low bending losses, resulting in a high integration density of components, and can be fabricated with the present industrial photolithography techniques. 13 Compared with other SPP waveguides, the dielectric core of the DLSPP waveguide structures can be easily designed to include an active medium 14 with gain and to achieve a high index contrast between the dielectrics and air.…”

“…Recently, most of the research about DLSPP waveguides has been concentrated in visible 12 and infrared, 18 spectral ranges. Little work has been carried out in the terahertz (THz) regime, which is also an important spectral range with many important applications.…”

Group-IV midinfrared plasmonics

“…For the wavelength λ ¼ 16 μm used in these simulations, guided modes exist only for waveguide cross sections larger than about 4 × 4 μm 2 , with the TM 0 mode being the last one to reach cut-off. A standard geometry for subdiffraction plasmonic waveguiding is the so-called dielectric-loaded waveguide, [23][24][25] where a thin dielectric slab is placed on top of a plasmonic film. Figure 2(b) shows that, by exploiting this concept, a Ge dielectric waveguide with a cross section as small as 4 × 1 μm 2 on top of an n-doped Ge film can sustain a propagating plasmonic mode.…”