Abstract
Coherent local excitation of surface plasmon polaritons (SPPs) by second-harmonic generation (SHG) in aligned crystalline organic functionalized para-phenylene nanofibers deposited on a thin silver film is demonstrated. The excited SPPs are characterized using angle-resolved leakage radiation spectroscopy in the excitation wavelength range of 850-1325 nm and compared to simulations based on a Green’s function area integral equation method. Both experimental and theoretical results show that the SPP excitation efficiency increases with decreasing wavelength in this wavelength range. This is explained both as a consequence of approaching the peak of the fibers nonlinear response at the wavelength 772 nm, and as a consequence of better coupling to SPPs due to their stronger confinement.
Highlights
Research efforts in the field of plasmonics and in the development of plasmonic circuitry have increased rapidly over the past decade
In principle there will be a surface plasmon polaritons (SPPs) excitation at the Fundamental Harmonic (FH) frequency due to scattering of the FH beam off the fiber similar to Ref [15]. which is not shown in Fig. 1(a), and which will not be detected in our experiment considered later since any FH signal is removed by filters
The angular distribution of SH radiation detected experimentally around the curved side of the glass prism (Fig. 1(b)) features two side lobes corresponding to generated SPPs, along with a central peak produced by SH light generated in the form of free propagating modes that are partially transmitted through the thin silver film in the forward direction (Fig. 4(a))
Summary
Research efforts in the field of plasmonics and in the development of plasmonic circuitry have increased rapidly over the past decade. In this work we demonstrate an alternative method, based on second harmonic generation (SHG) in crystalline organic nanofibers deposited on a thin metal film. This method has the advantage that the generated SPPs are coherent with the excitation light and near-infrared optical signals are converted to SPP signals in the visible range that are easier to detect or convert afterwards. The sub-wavelength dimensions of the nanofibers facilitate direct SHG into SPPs (Fig. 1(a)). In this way, nanofibers can serve as local coherent tunable SPP sources, i.e. within the vertical SPP decay length. This process is different from the SPP generation by linear polarization sources of illuminated nanofibers that were recently investigated [15]
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have