CaSTL Seminar by David Nesbitt

The powerful combination of i) ultrafast lasers, ii) multiphoton photoemission, and iii)
high numerical aperture in-vacuo objectives provides a remarkably flexible and sensitive
experimental platform for exploring chemical physics of plasmonic materials on the
nanoscale. This talk will provide an overview of recent progress in the group. 1) The first
topic will be on exploiting novel high repetition rate (75 MHz) ultrafast OPO oscillators
to probe plasmonic properties of isolated nanostructures via scanning photoemission
imaging microscopy (SPIM). 2) Next, significant enhancement of these methods with
velocity map imaging (VMI) of the ejected photoelectrons will be discussed, which
provides detailed angle and energy resolved information on the optical, electronic, and
Fermi level properties of single nanostructures. 3) Finally, we discuss very recent
extensions of these capabilities to fs time resolved pump-probe measurements, which
now provide information on fast relaxation dynamics and hot electron energy
distributions in single plasmonic nanostructures of potential importance in photocatalysis
applications.