Nonlinear Optical Responses Of Plasmonic Meatsurface With Sub-Nm Gaps Calculated By Tddft With Jellium Model

We theoretically investigate 3rd-order nonlinear response of plasmonic metasurfaces composed of twodimensionally arrayed metallic nanoparticles by a quantum mechanical approach. When the gap distance between the constituent nanoparticles reaches sub-nm scale, huge 3rd-order nonlinearity is observed, caused by the current through the gaps.