Scaling for gap plasmon based waveguides

Abstract

Using the effective-index approach and an explicit expression for the propagation constant of gap surface plasmon polaritons (G-SPPs) obtained for moderate gap widths, we introduce a normalized waveguide parameter characterizing the mode field confinement and obtain the corresponding expressions for various (gap, trench and V-groove) G-SPP based waveguides. Usage of the obtained relations is investigated with a finite-element method, demonstrating that waveguides with different dimensions and operating at different wavelengths, but having the same normalized parameter, exhibit very similar field confinement. These relations allow one to design G-SPP waveguides for single-mode operation supporting a well-confined fundamental mode.

Longwave plasmonics on doped silicon and silicides

“…Two structures that are beneficial for plasmonic circuits are the simple stripe and the parallelstripe "slotted" plasmonic waveguides [6]. These are illustrated in Fig here) will also work quite well.…”

Extremely confined gap surface-plasmon modes excited by electrons

“…However, GSP modes have, to our knowledge, never been experimentally examined with EELS. The GSP modes occur in a variety of geometries, from the simplest one-dimensional (1D) metal-insulator-metal (MIM) waveguide 23,24 and metal nanowire-on-film geometries 22 to advanced structures such as the convex groove, V-groove and trench and stripe waveguides 25,26 . Furthermore, GSP modes offer enhanced properties compared with the usual propagating SP mode, such as extreme light confinement with improved propagation distances 27,28 , negative refraction 29,30 , highly efficient light absorption 25 and electrically driven circuitry 31 , to name a few important and distinct features of GSP modes in plasmonics.…”

“…The geometry of these nanogrooves is characterized by gradual and relatively slow variations in the gap width when moving deeper inside a groove. This means that the groove GSP modes can be considered as being formed by local MIM GSP modes (that is, by GSP modes supported by constant-gap MIM configurations) that are weighted accordingly, a representation which is widely used in integrated optics and plasmonics for effective-index approximation 26 . In EELS experiments (Fig.…”

Excitation of fluorescent nanoparticles by channel plasmon polaritons propagating in V-grooves

“…The properties arising from their hybrid nature ͑e.g., shorter wavelength͒ can be exploited to overcome the diffraction limit and to squeeze light in submicrometric optoelectronic devices 3,4 SPPs that are laterally confined in subwavelength structures ͑e.g., in metal slits or gaps͒ are called channel plasmon polaritons ͑CPPs͒. [5][6][7] As a consequence of the confinement, CPPs present a shorter propagation length than SPPs excited in similar conditions. 6 However, the simultaneous confluence of strong confinement and a propagation loss sufficiently low for practical applications has been long out of reach.…”