Special Physics Seminar

Emerging Optics from Structured Nanomaterials

Danqing Wang

Department of Materials Science and Engineering
University of California, Berkeley

Miniaturized and rationally assembled nanostructures exhibit extraordinarily distinct physical properties beyond their individual units. This talk will focus on metal nanoparticle lattices that show unique diffractive coupling with lattice spacings engineered close to the wavelength of light. By harnessing different materials systems and lattice designs, various light-matter interactions can be engineered including nanoscale lasing and exciton-plasmon energy transfers. We achieved reconfigurable, mechanical control of nanoscale lasing by modulating lattice spacings of gold nanoparticles on an elastomeric substrate. Nanoparticle superlattices—finite-patches of nanoparticles grouped into microscale arrays—support multiple band-edge states for controlled multi-modal lasing. Integrating upconverting nanoparticles with metal nanoparticle lattices enables continuous-wave upconverting lasing at room temperature with record-low lasing thresholds. Deterministic coupling of single-photon emitters in 2D materials to these nanoscale cavities facilitated enhanced quantum emission and faster exciton decay dynamics. The structured nanomaterials can serve as a versatile, scalable platform for large-scale quantum optics, energy harvesting, and nontrivial topological photonics.