Delia Milliron Seminar
Metal oxide nanocrystals doped with a few percent of aliovalent dopants become electronically conducting and support strong light-matter interactions in the infrared due to localized surface plasmon resonance (LSPR). At the same time, they remain wide bandgap semiconductors, so they are transparent to visible light, offering unique spectrally selective opportunities to control light. In nanocrystals of the prototypical material tin-doped indium oxide (ITO), the strength and spectrum of light absorption is tunable across the mid- and near-infrared by varying the amount of tin incorporated during synthesis and the nanocrystal size and shape. These nanocrystals are ideal building blocks for optical metamaterials, where the spectra of the components and the nature of the coupling between them determine the effective optical response. Plasmonically enhanced electric fields in superlattices of ITO nanocrystals amplify the resonant vibrational signatures of organic molecules, which appear as Fano resonances. By mixing ITO nanocrystals with different tin doping concentration in superlattices, tunable absorption and reflectance bands are created. Integrating these versatile infrared materials into photonic structures, we demonstrate spectrally tunable perfect absorption by a single monolayer of nanocrystals. Looking ahead, we foresee opportunities to enhance both linear and nonlinear optical properties and to influence surface chemical reactions based on the extreme concentration of long wavelength light into nanometer scale volumes.
Dr. Delia Milliron's Biography
Delia J. Milliron is the T. Brockett Hudson Professor in Chemical Engineering at the University of Texas at Austin. Milliron leads a research team that focuses on developing and studying the properties of new electronic nanomaterials. Her team pursues studies on nanocrystals, nanoscale interfaces, and controlled assemblies of nanocrystals. Her team takes a systematic approach towards elucidating effects that arise at the nanoscale with a special focus on structure-property relationships.
