Channel Plasmon-Polariton Guiding by Subwavelength Metal Grooves

Abstract

We report on realization of channel plasmon-polariton (CPP) propagation along a subwavelength metal groove. Using imaging with a near-field microscope and end-fire coupling with a tapered fiber connected to a tunable laser at telecommunication wavelengths (1425-1620 nm), we demonstrate low-loss (propagation length approximately 100 microm) and well-confined (mode width approximately 1.1 microm) CPP guiding along a triangular 0.6 microm-wide and 1 microm-deep groove in gold. We develop a simple model based on the effective-index method that accounts for the main features of CPP guiding and provides a clear physical picture of this phenomenon.

Extreme-ultraviolet light generation in plasmonic nanostructures

“…In principle, our use of gold instead of silver as waveguide material may cause higher absorptive losses [94,47,39]. However, since the typical propagation lengths of surface plasmon polaritons in gold waveguides are still much larger than the length of the waveguides used [95,39], we believe that structural quality and durability play a far more significant role than material selection for achieving stable strong-field conditions. In this respect, using a bulk gold support allowing for smooth waveguide walls and high thermal Wave length (nm) Figure 4.2: (a) Nanostructure-enhanced EUV spectra (logarithmic scale) using xenon, argon and neon gas (200 mbar backing pressure) excited in the waveguide displayed in Fig.4.1(b) (inset, red frame).…”

“…Here, an efficient coupling of the CPPs depends critically on the geometry of the grooves. Calculations for rectangular gold channels indicate that propagation distances on the order of 200 µm are expected for certain CPP modes at 1.55 µm wavelength [95], allowing for a sufficient generation length in a HHG scheme with channel plasmons. Currently, attempts to realize channel-plasmon-enhanced HHG are in progress and are expected to enable a clear observation of high harmonic signals from nanostructures for the first time.…”

“…The efficient coupling of channel SPPs-channel-plasmon-polaritons (CPP)-into Vshaped grooves has already been demonstrated and characterized by near-field scanning optical microscopy (NSOM), as shown in Fig. 5.3 [95,108]. A smooth gold film is deposited on a fused silica substrate and contains V-shaped channels, which have a tailored geometry in terms of opening θ angle and depth d (see SEM image in Fig.…”

A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation

“…This geometry is of fundamental importance in nano-photonics, although the relatively large portion of energy propagating in the surrounding regions may restrict the compactness of the waveguide. On the other hand, plasmonic waveguides can provide subwavelength confinement by storing optical energy in electron oscillations within dissipative metallic regions [2][3][4][5][6][7][8][9][10][11][12][13]18 .…”

Analysis of the propagation of terahertz surface plasmon polaritons on semiconductor groove gratings

“…2 The twodimensional character of SPPs makes it possible to confine electromagnetic radiation below the diffraction limit, offering unprecedented possibilities for subwavelength optics. [3][4][5][6][7] A key aspect in surface plasmon optics or plasmonics is the control of the propagation of SPPs. A wealth of optical components for SPPs such as mirrors, beam splitters, couplers, and waveguides can be achieved by structuring the surface of the conductor.…”