Orientation‐Dependent Photoion Emission from Aerosolized Nanostructures

Abstract

The laser‐irradiated aerosolized nanostructures with complex geometries offer unique opportunities to steer orientation‐dependent photoion emission for multiple applications of directional ion sources and photocatalysis. The orientation‐dependent photoion emission is characterized by measuring the distribution and probability on differently oriented nanostructures. This unique capability is achieved by introducing momentum‐to‐space orientation discrimination in the single‐shot velocity map imaging technique with the aerodynamic lens. The effect of geometry, polarization, and concentration to control the photoion emission from differently oriented nanostructures is introduced for optimizing the potential applications of photoion emission including directional tunable nanoanode and optical sensors. The mechanism behind controlling the photoion emission is visualized by the variations in the regions of high laser intensity inside the nanostructures responding to the orientation, geometry, and polarization. This work represents an advance in characterizing the photoion emission from the randomly oriented aerosolized nanostructures and facilitates the potential for combining with the pump–probe methods to provide an intuitive understanding of their real‐time ionization dynamics.

Ion imaging of spatially inhomogeneous nanoplasmas in NaCl particles

“…Below, we focus on (i) variation in ion KE, (ii) asymmetry along the laser propagation direction and (iii) emission angle and discuss possible origins of observed variations. We also note that certain ion emission features could originate from variation in particle morphology (non-cubical) and clusters of particles 12,32,34 (e.g. dimers).…”