Using surface lattice resonances to engineer nonlinear optical processes in metal nanoparticle arrays

Abstract

Collective responses of localized surface plasmon resonances, known as surface lattice resonances (SLRs) in metal nanoparticle arrays, can lead to high quality factors (∼100), large local-field enhancements and strong light-matter interactions. SLRs have found many applications in linear optics, but little work of the influence of SLRs on nonlinear optics has been reported. Here we show how SLRs could be utilized to enhance nonlinear optical interactions. We devote special attention to the sum-frequency, difference-frequency, and third-harmonic generation processes because of their potential for the realization of novel sources of light. We also demonstrate how such arrays could be engineered to enhance higher-order nonlinear optical interactions through cascaded nonlinear processes. In particular, we demonstrate how the efficiency of third-harmonic generation could be engineered via cascaded second-order responses.

Efficient nonlinear metasurfaces by using multiresonant high-Q plasmonic arrays

“…We use the NDDA approach to understand how multiresonant metasurfaces can be realized by arranging nanoparticles into periodic arrays supporting SLRs. The treatment follows earlier work on utilizing SLRs in nonlinear optics [26][27][28].…”

“…The final step is to extend the above approach to the nonlinear process of SHG. A more general case has been considered earlier with a focus on singly resonant metasurfaces [27]. We assume that the undepleted-pump approximation holds, allowing us to write the SHG dipole moment component for the jth particle as…”

“…The SHG response of a metasurface can now be predicted with the aid of the above equations [27,28]. Specifically, the form of Eq.…”

“…However, relatively high-Q-factor resonances (Q > 100) can be achieved by arranging metal nanoparticles into periodic arrays, where particles become optically coupled and give rise to very narrow resonances, known as surface lattice resonances (SLRs) [15][16][17][18]. In fact, SLRs have already been utilized in many applications [19][20][21][22], where several works have also investigated their potential for nonlinear optics [23][24][25][26][27][28][29]. However, the nonlinear responses of multiresonant and high-Q-factor SLR arrays have not yet been investigated.…”

Geometric frustration in a hexagonal lattice of plasmonic nanoelements

“…Moreover, the optical response of the system may also be governed by the near-field coupling between nearest neighbors giving rise to Localized Surface Resonances (LSR). Whereas LSR usually exhibit broad extinction peaks due to radiative damping, SLR present sharp linewidths that could be more suitable for applications profiting from a high frequency specificity [21][22][23][24][25]. Interestingly, for incoming radiation around normal incidence and with a wavelength matching one of the diffraction edges of the Bravais lattice of the array, a SLR mode due to the lattice diffraction shows up.…”