Giant enhancement of sum-frequency yield by surface-plasmon excitation

Abstract

We show experimentally that the radiation generated in infrared-visible sum-frequency mixing at an airsilver interface can be greatly enhanced when the visible input beam excites a surface plasmon-polariton at the interface. With either a prism or a grating used to couple the visible radiation with the surface polariton, the sum-frequency-generation yield is observed to be enhanced by a factor of 10 2 for the prism and 10 4 for the grating for counterpropagating infrared and visible input beams. The result for the prism configuration can be simply understood in terms of the field enhancement associated with the surface polariton excited by the visible input beam. For the grating configuration there is an additional effect in that the nonlinear polarization at the sum frequency can also couple with a surface polariton. As a result the effective interaction length of the sum-frequency-mixing process is sizably increased. The experimental results are in good agreement with estimates based on this model.

Sum-Frequency Spectroscopy Amplified by Plasmonics: The Small Particle Case

“…One way to overcome this issue is to compensate for the lack of sensitivity by an experimental amplification of the produced SFG. Several possibilities exist, usually related to a local amplification of the electric fields of light through a coupling to surface plasmon polaritons 4 , resonant microcavities 5 or evanescent waves in attenuated total reflection geometry 6,7 . Recently, a new route towards amplification has been explored by coupling SFG production to the excitation of localized surface plasmons of nanostructures [8][9][10][11][12][13][14][15][16] , as happens for SERS for example.…”

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

“…To date, several plasmonenhanced nonlinear optical phenomena have been explored, including second-harmonic generation (SHG) from deterministic [14,52], random [53][54][55], and phase-matched [56] nanostructured surfaces. While SHG can be realized with a quasi-monochromatic light source of a fundamental wave (FW), the sum-frequency generation (SFG) [57,58] or difference-frequency generation (DFG) [59] in plasmonic materials is more difficult to realize experimentally; this is because it requires two such sources with distinct carrier frequencies as, in general, does surface plasmon excitation by four-wave mixing [15,16]. These second-and third-order nonlinear processes are surface sensitive at the molecular level, rendering them highly attractive for nonlinear microscopy.…”

Plasmonic Gold Nanohole Arrays for Surface-Enhanced Sum Frequency Generation Detection

“…However, attempts to explore the mechanisms of SPP-driven SFG are still in a primary state. So far, there have been comparatively less attempts at the enhancement efficiency of SPP-driven SFG, such as surface roughness [ 24 ], efficient propagating configurations [ 25 , 26 ], and magnetization [ 27 ]. Understanding the optical performance of SPP and its relation with SFG will be helpful for the application of SPP-driven SFG surface analysis.…”