Efficient Nonlinear Metasurfaces using Multiresonant High-Q Plasmonic Arrays

Harmonic generation at the nanoscale

“…A more intriguing approach suggested by Czaplicki and colleagues [Czaplicki et al (2016)] consists in exploiting the lattice modes sustained by a less dense array of nonlinear nanoantennas. In this framework, it has been recently theoretically predicted an enhancement factor of about 10 6 with respect to an individual plasmonic nanoantenna, obtained when the array features active lattice modes at both the pump and emission wavelength as shown in Figure 4c [ Huttunen et al (2019)].…”

“…poled plasmonic metasurface to enhance and redirect SHG [Segal et al (2015)]. c) A plasmonic metasurface that exploits surface lattice modes at both the pump and emission wavelength for the enhancement of the SHG [Huttunen et al (2019)]. d) A plasmonic metasurface for the generation of nonlinear chiral light [Li et al (2017)].…”

Giant midinfrared nonlinearity based on multiple quantum well polaritonic metasurfaces

“…Building on previous explorations for MQW parameters that improve SHG efficiency according to (1), there are still several unexplored venues for the MS design that may enhance the efficiency in (1). While a simple inspection of (1) indicates that the MS design should support large field intensity enhancement, recent attempts have been focused on two enhancement strategies: nanoparticle arrays associated with narrow resonances and high-quality factors (Q-factors), for instance, supporting SLRs [37,42,43]; multiply-resonant nanostructures for which the resonance enhancement occurs both at pump wavelength and at the SH wavelength [13][14][15]. However, it is important to realize that high field enhancements at both frequencies will not necessarily result in improved efficiency.…”

“…They are collective resonances that arise when individual nanostructures couple to in-plane diffraction orders [47,48]. The most basic SLR arises when the MS periodicity equals the wavelength at the cutoff of the ±1st diffraction orders, forming standing waves whose quality factor depends on the localized surface plasmon resonance (LSPR) of the inclusion [43,49]. SLRs are typically characterized by high Q factors, and they have been explored to enhance the weak nonlinear optical responses of conventional MS [43].…”

“…The most basic SLR arises when the MS periodicity equals the wavelength at the cutoff of the ±1st diffraction orders, forming standing waves whose quality factor depends on the localized surface plasmon resonance (LSPR) of the inclusion [43,49]. SLRs are typically characterized by high Q factors, and they have been explored to enhance the weak nonlinear optical responses of conventional MS [43]. The inclusions themselves can support any kind of additional resonance, as desired, which is particularly useful to enhance the overlap integral between fundamental frequency and SH.…”