Enhanced Four-Wave Mixing in Doubly Resonant Si Nanoresonators

Abstract

Frequency conversion is one of the main applications of nonlinear optical processes in which a signal is produced at a different wavelength from the excitation wavelength.In particular, four-wave mixing (FWM) is a third order non-linear optical process that allows, for instance, the generation of visible frequencies by tuning near-infrared laser pumps. Here, in order to augment the very weak FWM conversion efficiency, we design silicon Mie resonators that exhibit two resonances of the internal electric field intensity 1 around the frequency range of the laser pumps. The linear extinction spectrum of the individual Si resonator is first measured by bright field spectroscopy and compared with numerical simulations to confirm the existence of the two resonances corresponding to electric and magnetic dipoles excitations. The FWM signal is then measured for a single Si nanoresonator when the first pump is set to the electric resonance, while tuning the frequency of the second pump across the magnetic dipolar resonance. We show that the FWM signal generated in the visible spectrum is maximum when the frequency of the tunable pump corresponds to the maximum of the internal electric field intensity.At this position, the FWM signal is enhanced by more than two orders of magnitude compared with the FWM signal generated by the unpatterned silicon film.

High-harmonic generation at the nanoscale boosted by bound states in the continuum

“…Recently, anapole resonance in a silicon nanodisk on a gold substrate enabled THG with 10 −4 conversion efficiency [15]. Degenerate wave mixing driven by third-order nonlinearities in isolated germanium and silicon nanodisks has also been reported recently [16,17]. Second-order nonlinear effects in Mie resonators have been considered as well in III-V semiconductors, in perovskites, and in metal-oxide nanoparticles [18][19][20][21][22][23][24].…”

Infrared upconversion imaging in nonlinear metasurfaces

“…Traditionally, the stronger nonlinear intensity of a metasurface is associated to the near-field enhancement at the fundamental wave. 27,32 However, the efficiency of the nonlinear frequencymixing also depends on the spatial mode overlap of the interacting waves [45][46][47] [Figs. 2(d) and 2(e)].…”

Nonlinear Optics in Dielectric Guided-Mode Resonant Structures and Resonant Metasurfaces

“…The higher order anapolar mode profiles are chosen with good spatial overlap to ensure enhancement of the SFG process by about two-orders of magnitude, as shown in the SFG spectrum in Figure 17f. Silicon (Si) nanodisks that support magnetic and electric-dipole resonances have also been utilized for doubly-resonant enhancement of FWM process as shown in Figure 17g-i [108]. The individual resonance spectra and the corresponding resonance for the FWM are also shown, with approximately two-orders of magnitude enhancement.…”

“…[105], d-f are reproduced with permission from ref [107],. g-i are reproduced with permission from ref [108]. and j-l are reproduced with permission from ref [109]…”