Optical seminar | 07 August 2020

Shi-Wei Chu
National Taiwan University
Giant photothermal nonlinearity of plasmonics and silicon nanostructures - applications toward super-resolution imaging
During the last decade, the diffraction limit of resolution was beautifully overcome by manipulating the on/off switching of fluorophores, or by saturation of fluorescence emission, resulting in resolution below 100 nm. Nevertheless, fluorescence exhibits intrinsic photobleaching issue. In this seminar, I will introduce novel nonlinear behavior of scattering in a single plasmonic/semiconductor nanoparticle, which amplifies photothermal nonlinearity of bulk by at least three orders, with unusually rapid nanosecond response, via anapole or Mie-resonance enhanced absorption. This giant/fast nonlinearity enables 90% reversible/repeatable all-optical-modulation at GHz, and the first scattering-based 40-nm super-resolution imaging of silicon. Potential applications range from biomedical imaging to next-generation active Si photonics.