Second-harmonic generation from metallodielectric multilayer photonic-band-gap structures

Abstract

We experimentally and theoretically investigate the second order nonlinear optical response of metallo-dielectric multilayer structures composed of Ag and Ta 2 O 5 layers, deposited by magnetron sputtering. Second harmonic generation measurements were performed in reflection mode as a function of incidence angle, using femtosecond pulses originating from a Ti:Sapphire laser system tuned at λ=800 nm. The dependence of the generated signal was investigated as a function of pump intensity and polarization state. Our experimental results show that the conversion efficiency from a periodic metallo-dielectric sample may be enhanced by at least a factor of 30 with respect to the conversion efficiency from a single metal layer, thanks in part to the increased number of active surfaces, pump field localization and penetration inside the metal layers. The conversion efficiency maximum shifts from 70° for the single silver layer down to approximately 55° for the stack. The experimental results are found to be in good agreement with calculations based on coupled Maxwell-Drude oscillators under the action of a nonlinear Lorentz force term.2

Second-harmonic generation in metallic nanoparticles: Clarification of the role of the surface

“…In particular, a steady stream of works concerning harmonic generation from metallic nanostructures, such as hole arrays in a metallic substrate, 38-43 metallodielectric multilayer structures, 44,45 Au nanoantennas, 46,47 and periodic nanostructured metal films, 48,49 have been published recently. Secondharmonic generation has also been observed experimentally from ordered arrays of split-ring resonators, 50,51 as well as from a variety of single nanoparticles [52][53][54][55][56] and nanoparticle arrays with varying geometries.…”

Classical theory for second-harmonic generation from metallic nanoparticles

“…Recently, a renaissance of scientific interests appears in the quadratic nonlinearities of metallic nanostructures and nanoparticles (NPs) partially owing to the significant localizations of electromagnetic (EM) field induced by the plasmonic oscillations of the conduction electrons inside the metal [25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47]. More specifically, SHG were experimentally observed from different geometric configurations such as sharp metal tips [28,32], periodic nanostructured metal films [29], imperfect spheres [31,35], split-ring resonators [34,40] and their complementary counterparts [42], metallodielectric multilayer photonic-bandgap structures [41], T-shaped [40] and L-shaped NPs [38,43], noncentrosymmetric T-shaped nanodimers [39,46] and "fishnet" structures [44].…”

“…More specifically, SHG were experimentally observed from different geometric configurations such as sharp metal tips [28,32], periodic nanostructured metal films [29], imperfect spheres [31,35], split-ring resonators [34,40] and their complementary counterparts [42], metallodielectric multilayer photonic-bandgap structures [41], T-shaped [40] and L-shaped NPs [38,43], noncentrosymmetric T-shaped nanodimers [39,46] and "fishnet" structures [44].…”

Third-harmonic generation in the presence of classical nonlocal effects in gap-plasmon nanostructures

“…Metals have long been recognized as compelling candidates for nonlinear materials, as they possess nonlinear susceptibilities that are orders of magnitude larger than dielectric materials, and support surface plasmon modes that allow the light to become strongly confined and enhanced in deeply sub-wavelength volumes. As a result, a major research effort has been targeted toward metal-dielectric composites 1,2 , including metallodielectric stacks [3][4][5] , metamaterial composites 6-10 , structured films 11,12 and surfaces [13][14][15] . While the absorption inherent to metals is generally considered to be detrimental for linear applications, it is far less critical for nonlinear optical applications because conversion rates are expected to be smaller than a fraction of a percent.…”