Plasmon-enhanced spectral changes in surface sum-frequency generation with polychromatic light

Abstract

We theoretically explore the spectral behavior of the fundamental and sum-frequency waves generated from the surface of a thin metal film in the Kretschmann configuration with coherent ultrashort pulses. We show that the spectra of reflected sum-frequency waves exhibit pronounced shifts for the incident fundamental waves close to the plasmon coupling angle. We also demonstrate that the scale of discovered plasmon-enhanced spectral changes is strongly influenced by the magnitude of the incidence angle and the bandwidth of the source spectrum.

Surface second-harmonic generation from metallic-nanoparticle configurations: A transformation-optics approach

“…Other problems that can be solved with the same approach are 3D structures [7,61], SHG at other spectral regimes, e.g., in the THz regime [62], optical rectification, and more complex nonlinear wave interactions, such as 3 wave mixing [63][64][65], phase-conjugation [66] or even additional effects such as the role of non-locality [14,15] on SH and many more.…”

Nonlinear optics in all-dielectric nanoantennas and metasurfaces: a review

“… – 41 Metasurfaces enabling SHG have been constructed by choosing specific geometries of the meta-atoms, such as L-shaped 42 – 47 and G-shaped antennas, 48 – 52 split-ring resonators, 27 , 53 – 58 asymmetric dimmers, 59 , 60 dielectric-loaded plasmonic 3-D structures, 61 and multiresonant antennas, 62 – 65 where the inversion symmetry is absent. Plasmonic metasurfaces have been employed for other second-order processes like sum-frequency generation (SFG) 66 , 67 and difference-frequency generation (DFG) 68 – 70 In contrast, third-order nonlinear effects, such as the Kerr effect, 71 – 73 third-harmonic generation (THG), 29 , 31 , 74 – 77 and four-wave mixing (FWM), 23 , 25 , 78 – 83 are free from symmetry considerations for linear polarized light.…”

Giant spectral transformations in plasmon-enhanced difference-frequency generation with polychromatic light

“…We are, however, using a single polychromatic source, which eliminates the need for multiple sources and also has the added advantage of generating spectral signatures and enhancing the DFW close to the plasmon resonance angle. The spectral signatures of a surface sum-frequency wave reflected from a thin gold film using polychromatic light have been previously reported [33], with significant spectral shifts in the spectrum shown close to plasmon resonance. We report more pronounced shifts and enhancement in the difference-frequency spectrum close to plasmon resonance.…”

“…We can better highlight the spectral effects of DFG in our system by normalizing the DFW spectrum to the corresponding maximum for each angle of incidence [33] as shown in figure 3(b). We observe significant shifts in our spectrum between the plasmon resonance angles of  42.6 and  43.5 .…”