Scanning Photoionization Imaging Microscopy and Ultrafast Kinetics of Plasmonic Nanomaterials with Applications to Chiral Induced Spin Selectivity (CISS)
Abstract
We will exploit ultrafast OPO lasers and Scanning Photoemission Imaging Microscopy (SPIM) methods developed in our group to study photoelectron photoemission dynamics from “engineered� plasmonic nanostructures (e.g., Au-Ag nanorods, nanoshells, nanostars), based on polarization-frequency dependent multiphoton photoionization, coupled with time resolved velocity map imaging (VMI) of the resulting photoelectron flux. We will upgrade the current 2D electron velocity map imaging system with fast (~ 60 ps) electron triggering and counting capabilities to achieve to full 3D (px, py, pz) resolution, which will permit rigorous determination of the nascent vector photoemission distributions. We will extend these ultrafast plasmonic microscopy methods to control spatial and spin degrees of electronic freedom, exploiting right (RCP) and left (LCP) hand circularly polarized ultrafast light sources to study multiphoton generation and transmission of spin polarized electrons through chiral dsDNA helices, building on the pioneering single photon chiral induced spin sensitivity (CISS) studies of Naaman, Waldeck, and coworkers. We will combine SPIM and CISS methods to explore spin polarized electron photoemission dynamics from multiphoton (n = 2-4) excited plasmonic states prepared by illumination of plasmonic nanomaterials. In particular, we will harness these novel microscopies to explore photoemission from chiral plasmonic nanoobjects, which for RCP vs. LCP ultrafast excitation can yield modulation in the electron spin polarization and be quantified with chiral dsDNA filters-3D velocity map imaging. Finally, we will leverage confocal-wide field microscopy expertise in our group for temperature-pressure controlled folding kinetic studies of RNA “riboswitches� at the single molecule level, to help develop-refine RNA biosensors of Air and Space Force interest in the detection of stress biomarkers and explosive materials with unprecedented sensitivities.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 06, 2024
- Source ID
- FA95502310442
Entities
People
- David J. Nesbitt
Organizations
- Air Force Office of Scientific Research
- Regents of the University of Colorado
- United States Air Force