Strong second-harmonic generation from Au–Al heterodimers

Abstract

Strong second-harmonic generation from Au–Al heterodimers with a nanogap is observed and predicted, mainly attributed to coupling of plasmonic resonance in the fundamental field and synergistic driving from constituting nanoantennas in the SH field.

‘Plug-and-play’ plasmonic metafibers for ultrafast fibre lasers

“…1(b5) shows a typical metasurface made of a nanorod array fabricated on an SMFJ endface using this technique (see 'Nanofabrication of the metafiber using EBL' in Supplementary Information for details). The advantages of such methods include low cost and high immunity to complicated plasmonic systems, such as heterodimers [9,34,35].…”

“…As illustrated in the inset of Fig. 6(d), the surface plasmons provide a dramatic local field enhancement for the electric field E, especially when their resonances match the fundamental or high-order harmonic excitation frequencies [9,65,66]. Furthermore , the surface components of nonlinear susceptibilities, for example, 𝜒 (3) 𝑠𝑢𝑟 𝑓 in the process of two-photon absorption, will be significantly altered owing to the hot carrier redistributions during strong light-matter interactions [35,45,46,67].…”

“…Plasmonic metasurfaces are formed by artificially patterning subwavelength nanostructures in two-dimensional (2D) arrays [1,2,3,4]. Their plasmonic resonances are intentionally designed by altering the spatial distribution and orientation of unit cells to improve the interactions of the impinging light by enhancing the absorption and scattering cross sections, both in linear and nonlinear optical regimes [5,6,7,8,9,10]. Indeed, the nonlinear absorption of plasmonic metasurfaces has attracted increasing interest in recent years for state-of-the-art applications, including frequency conversion [6,9], neuromorphic circuits [11,12,13], and ultrashort laser pulse generation [14,15].…”

“…Their plasmonic resonances are intentionally designed by altering the spatial distribution and orientation of unit cells to improve the interactions of the impinging light by enhancing the absorption and scattering cross sections, both in linear and nonlinear optical regimes [5,6,7,8,9,10]. Indeed, the nonlinear absorption of plasmonic metasurfaces has attracted increasing interest in recent years for state-of-the-art applications, including frequency conversion [6,9], neuromorphic circuits [11,12,13], and ultrashort laser pulse generation [14,15]. Pioneering studies employed plasmonic metasurfaces as saturable absorbers (SAs) in a fibre laser, leading to soliton mode locking [15,16].…”

Investigating Route to Chaos in Nonlinear Plasmonic Dimer

“…In most of those areas, localized surface plasmons behave linearly with the excitation, the light intensity is proportional to the illumination and remains monochromatic if the source itself is. However, the large field enhancement close and inside noble metal nanoparticles allows to activate nonlinear behaviors like second- [9] or third-order [10] processes. An archetypal system in plasmonics is a metal dimer composed of two simple shape nanoobjects (spheres, rods, disks) separated by a small gap, which behave like an optical antenna at the nanoscale, [11,12] and whose plasmonic modes result in a field more or less enhanced and confined within the gap area.…”