Observation of few-cycle, strong-field phenomena in surface plasmon fields

Abstract

We present experimental evidence of the generation of few-cycle propagating surface plasmon polariton wavepackets. These ultrashort plasmonic pulses comprised of only 2-3 field oscillations were characterized by an autocorrelation measurement based on electron photoemission. By exploiting plasmonic field enhancement, we achieved plasmon-induced tunnelling emission from the metal surface at low laser intensity, opening perspectives for strong-field experiments with low pulse energies. All-optical electron acceleration up to keV kinetic energy is also demonstrated in these surface-confined, few-cycle fields with only 1.35×10(12) W/cm2 focused laser intensity. The experimental results are found to be in excellent agreement with the model.

Mechanisms of THz generation from silver nanoparticle and nanohole arrays illuminated by 100 fs pulses of infrared light

“…These energies are much higher than the photon energy, 1.55 eV, indicating the ponderomotive electron acceleration mechanism [30,31]. A cutoff electron energy is apparent in these data at ß20-40 eV; this cutoff energy scales linearly with the incident intensity for low incident pulse intensities, which also points towards a mechanism involving ponderomotive electron acceleration (see [30,31] as well as supporting info for [15]). The integrated photocurrent as a function of incident intensity for both array types is shown in Fig.…”

Surface plasmon assisted electron acceleration in photoemission from gold nanopillars

“…The goal of the present work is to investigate the interactions of laser-ionized photoelectrons with localized surface plasmon electric fields excited in a lithographically prepared nanostructured array. The use of a nanostructured surface is advantageous because the SPRs are excited directly by ultrafast laser pulses without requiring special excitation geometries often used in studies of plasmon enhanced photoemission from flat gold surfaces [7][8][9][10][11][12][13][14] or extremely sharp metal tips 15,16 . By measuring photoelectron kinetic energy spectra and electron yields as a function of laser excitation intensity, we observe photoelectron kinetic energies tens of eV higher than expected based on the laser excitation intensity.…”

Optical field emission from resonant gold nanorods driven by femtosecond mid-infrared pulses

“…Nonlinear photoelectron emission, a prominent phenomenon in this area, has been intensively studied for various individual metallic nanostructures, 1-9 thin films 10,11 or antenna arrays, [12][13][14][15] with motivations for optically-controlled electron propagation in ultrafast electronics, 16 ultrafast electron [17][18][19] and x-ray sources, 20 as well as phase-resolved imaging and spectroscopy. 16,21 Metal nanotips displaying broadband near-field enhancements present a prominent model system for highly nonlinear photoelectron emission and acceleration, and studies have been conducted in the visible to near-infrared, 1,3,7,22,23 mid-infrared 6 and Terahertz ranges 16,24 Nanoparticles and plasmonic antennas constitute another platform for photoemission studies, 8,9,15,25 as they exhibit field enhancements from resonant surface plasmon modes, [25][26][27] which may be further amplified by geometric edge enhancements.…”