Fowler-Nordheim emission modified by laser pulses in the adiabatic regime

TL;DR

This paper studies how laser pulses can enhance Fowler-Nordheim electron emission by applying the adiabatic approximation to oscillating electric fields, revealing increased tunneling currents under certain conditions.

Contribution

It introduces a method to analyze enhanced field emission using the adiabatic approximation for oscillating fields in the Fowler-Nordheim regime, extending beyond traditional approximations.

Findings

Enhanced emission due to oscillating fields under adiabatic conditions.

Average tunneling current can significantly exceed that of a static field.

Wave function inside the barrier is monotonically decreasing without oscillations.

Abstract

We investigate enhanced field emission due to a continuous or pulsed oscillating field added to a constant electric field $E$ at the emitter surface. When the frequency of oscillation, field strength, and property of the emitter material satisfy the Keldysh condition $\gamma<1/2$ one can use the adiabatic approximation for treating the oscillating field, i.e. consider the tunneling through the instantaneous Fowler-Nordheim barrier created by both fields. Due to the great sensitivity of the emission to the field strength the average tunneling current can be much larger than the current produced by only the constant field. We carry out the computations for arbitrary strong constant electric fields, beyond the commonly used Fowler-Nordheim approximation which exhibit in particular an important property of the wave function inside the potential barrier where it is found to be monotonically decreasing without oscillations.