Nonadiabatic Nano-optical Tunneling of Photoelectrons in Plasmonic Near-Fields

Abstract

Nonadiabatic nano-optical electron tunneling in the transition region between multiphoton-induced emission and adiabatic tunnel emission is explored in the near-field of plasmonic nanostructures. For Keldysh γ values between ∼1.3 and ∼2.2, measured photoemission spectra show strong-field recollision driven by the nanoscale near-field. At the same time, the photoemission yield shows an intensity scaling with a constant nonlinearity, which is characteristic for multiphoton-induced emission. Our observations in this transition region were well reproduced with the numerical solution of Schrödinger’s equation, mimicking the nanoscale geometry of the field. This way, we determined the boundaries and nature of nonadiabatic tunneling photoemission, building on a key advantage of a nanoplasmonic system, namely, that high-field-driven recollision events and their signature in the photoemission spectrum can be observed more efficiently due to significant nanoplasmonic field enhancement factors.

Carrier-envelope phase on-chip scanner and control of laser beams

“…At the same time, the ability to directly access the evolution of the electric field shape through CEP has been a key ingredient in attosecond science 24 . However, as most experiments are conducted in the vicinity of the laser focus where the spatial distribution of CEP is non-trivial 25 , 26 , demonstrations of CEP-sensitive interactions with larger structures, such as photoemission from arrays of nanoparticles 15 , 27 – 29 , surface-enhanced Raman scattering on adsorbed molecules 30 , high-harmonic generation from gases and especially solids 31 , 32 , current in reconfigurable circuits 33 , or petahertz networks 23 , 34 , are still pending, as the scaling of such systems is limited due to volume smearing effects. Here, we present a method for measuring and controlling CEP spatial distributions that enable the establishment of areas of well-defined CEP volumes.…”

The Influence of Geometry on Plasmonic Resonances in Surface- and Tip-Enhanced Raman Spectroscopy

“…It is known that many factors, such as the material, size, shape, and dielectric environment, play important roles in determining the LSPR [30]. Among these factors, the geometry [31][32][33][34][35][36][37] of the plasmonic nanostructure provides the largest freedom and a straightforward way to tune the plasmonic resonance condition. Therefore, in this chapter, we focus on different geometries of plasmonic structures starting from introducing mathematical solutions for a single metal sphere representing a monomer system and two coupled metal spheres representing a dimer system.…”

Analytical Model of Optical-Field-Driven Subcycle Electron Tunneling Pulses from Two-Dimensional Materials

“…Other than metallic nanostrucutres, ,,,− emerging two-dimensional (2D) materials − were recently employed to study their optical-field photoemission, as well, due to the distinctive electronic band structures and nanoscale sharpness. For instance, the most common 2D material, graphene, has an atomic-scale thickness, resulting in significantly high field enhancement near the edge, high electron mobility, and a high thermal damage threshold, which allows effective ultrafast optical-field electron tunneling emission from graphene .…”