Femtosecond thermionic emission from metals in the space-charge-limited regime

Abstract

We study femtosecond-laser-pulse-induced electron emission from W(100), Al(110), and Ag(111) in the subdamage regime (1-44 mJ/cm 2 fluence) by simultaneously measuring the incident-light reflectivity, total electron yield, and electron-energy distribution curves of the emitted electrons. The total-yield results are compared with a space-charge-limited extension of the Richardson-Dushman equation for short-time-scale thermionic emission and with particle-in-a-cell computer simulations of femtosecond-pulsed-induced thermionic emission. Quantitative agreement between the experimental results and two calculated temperaturedependent yields is obtained and shows that the yield varies linearly with temperature beginning at a threshold electron temperature of -0.25 eV The particle-in-a-cell simulations also reproduce the experimental electronenergy distribution curves. Taken together, the experimental results, the theoretical calculations, and the results of the simulations indicate that thermionic emission from nonequilibrium electron heating provides the dominant source of the emitted electrons. Furthermore, the results demonstrate that a quantitative theory of space-charge-limited femtosecond-pulse-induced electron emission is possible.

The laser assisted field electron emission from carbon nanostructure

“…Results of our experiment shown in Fig. 4 confirm that multiphoton photoemission dominates the electron yield [24] when the pulse energy is below 0.1 mJ.…”

“…In order to take into account the space charge, which is formed at the laser pulse front [21,24], we use approach [24], which describes the thermionic emission taking into account multiphoton processes. One can see from the Fig.…”

Quantum-classical model for the surface plasmon enhanced photoemission process at metal surfaces

“…In that way the thermally assisted photoemission process [30,31] in which electrons in the high-energy tail of the transient thermal distribution play a significant role can be disregarded in the present case. Thus, in order to describe the primary step of the SP stimulated emission process, we have chosen to use a perturbative quantum-mechanical method called "jellium-Volkov" (JV) [25] which is less time consuming than nonperturbative approaches such as the time-dependent Schrödinger equation resolution [25,32] or more refined timedependent density functional theory methods.…”

Spin-resolved photoelectron spectroscopy using femtosecond extreme ultraviolet light pulses from high-order harmonic generation

“…The energy distribution of the resulting photoelectrons has a tail reaching kinetic energies as high as the photoelectrons excited from the valence bands with our XUV beam. 55 The yield of this process strongly depends on the light peak intensity, light polarization, and the illuminated position of the sample surface. The latter fact points to a crucial role of the sample quality and surface roughness.…”