Metamaterials have demonstrated important potential for enhancing nonlinear processes on the nanoscale. The presence of narrowband hot-spots and extremely inhomogeneous mode-field distributions typically restrict the enhancement of nonlinear interactions over bigger spatial scales. This has posed a formidable problem in attaining simultaneous enhancement throughout a broadband spectral vary, considerably constraining the potential of photonic nanostructures in enhancing nonlinear frequency conversion. Right here, we suggest a broadband resonant mode matching methodology by way of near-field examinations that helps the multipole modes and permits the event of an ultrabroadband-enhanced 3–5 μm mid-infrared frequency upconversion method using a hyperbolic triangular pyramidal metasurface. The gap-plasma mode of the hyperbolic metamaterial multilayer system excites narrowly high-order resonances at near-infrared pump mild wavelengths, whereas the slow-light impact generated by the dipoles achieves ultrabroadband near-field enhancement at mid-infrared wavelengths. The symmetry breaking of the triangular construction localizes these resonant modes on the ideas, enabling mode-matched modulation at completely different wavelengths, and thus boosting the nonlinear frequency conversion course of. Our method supplies a promising platform for metasurface-based frequency conversion strategies.
