Optical Control of Field-Emission Sites by Femtosecond Laser Pulses

TL;DR

This paper demonstrates the use of femtosecond laser pulses to control and modulate field-emission sites on a tungsten tip with nanometer precision, enabling ultrafast, site-selective electron emission.

Contribution

It introduces a method to manipulate field-emission patterns using laser polarization and incidence, achieving ultrafast, nanoscale site selectivity on a tungsten tip.

Findings

Asymmetric emission pattern modulations depend on laser polarization.

Ultrafast pulsed emission with 10 nm site selectivity achieved.

Simulations match experimental emission patterns quantitatively.

Abstract

We have investigated field emission patterns from a clean tungsten tip apex induced by femtosecond laser pulses. Strongly asymmetric modulations of the field emission intensity distributions are observed depending on the polarization of the light and the laser incidence direction relative to the azimuthal orientation of tip apex. In effect, we have realized an ultrafast pulsed field-emission source with site selectivity on the 10 nm scale. Simulations of local fields on the tip apex and of electron emission patterns based on photo-excited nonequilibrium electron distributions explain our observations quantitatively.