Detall

Conferenciant: Kevin M. McPeak (Louisiana State University, USA).

Resum: I will discuss two distinct research thrusts my laboratory has pursued over the last several years, i.e., investigating resonant plasmonic-biomolecular interactions and the emergent optical and electronic properties of noble-transition metal alloys.

Resonant plasmonic-molecular chiral interactions are a promising route to enhanced biosensing. However, biomolecular optical activity primarily exists in the far-ultraviolet regime, posing significant challenges for spectral overlap with current nano-optical platforms. I will show experimentally and computationally the enhanced chiral sensing of a resonant plasmonic-biomolecular system operating in the far-UV. Our calculations show that detectable enhancements in the chiroptical signals from small amounts of biomolecules are possible only when tight spectral overlap exists between the plasmonic and biomolecular chiral responses. We support this conclusion experimentally by using Al gammadion arrays to enantiomerically discriminate ultrathin (< 10 nm thick) films of Tyrosine. Our results demonstrate the importance of using far-UV active metasurfaces for enhancing natural optical activity.

Noble-transition metal alloys are a new class of materials for interband-driven hot hole generation with NIR light. NIR hot-carrier generation in pure, noble metals suffers from insufficient energy to exceed the interband energy threshold (IET) (e.g.,> 2 eV), and in pure transition metals, rapid hot-carrier thermalization. Band hybridization in select noble-transition metal alloys can overcome these issues, yielding emergent properties that facilitate tuning the hot-carrier distribution and lifetime.