Ultra-large optical nonlinearity in metamaterials
Shi-Wei Chu1*
1Physics, National Taiwan University, Taipei, Taiwan
* Presenter:Shi-Wei Chu, email:swchu@phys.ntu.edu.tw
Recently, meta-optics based on innovative nanostructures has attracted significant attention in scientific community because of their superior properties in local-field enhancement and ultrasmall mode volume. For practical applications such as all-optical switch, optical nonlinearity of metamaterials is indispensable. However, the intrinsic nonlinear responses of most nanomaterials are not adequate. In this invited talk, I will review our recent findings on ultra-large optical nonlinearity in metallic and dielectric nanostructures. With ~100 nm particles, significant nonlinear response on scattering was found, based on resonant heating of the nanostructure as well as strong photothermal effect. The excitation intensity is typically less than 10 mW/um^2, which is much smaller than most nonlinear optics requirements, and thus leading to effective nonlinear coefficient n2 that is several orders larger than the bulk counterparts. I will present the applications of such a huge nonlinearity in a single nanostructure toward ultrasmall all-optical switch and label-free super-resolution microscopy.

Keywords: nonlinear optics, photothermal effect, plasmonics, meta-optics