Controlling the Photoelectric Effect in the Time Domain

TL;DR

This paper demonstrates control over the photoelectric effect in the time domain by using attosecond pulses and a weak infrared field to manipulate electron emission, challenging traditional quantum predictions.

Contribution

It introduces a novel method to control photoelectron emission direction and energy using ultrafast light pulses, extending coherent control techniques to the photoelectric effect.

Findings

Controlled electron emission asymmetry in helium

Manipulated photoelectron energy distribution

Contradicted traditional quantum-mechanical predictions

Abstract

When an atom or molecule absorbs a high-energy photon, an electron is emitted with a well-defined energy and a highly-symmetric angular distribution, ruled by energy quantization and parity conservation. These rules seemingly break down when small quantum systems are exposed to short and intense light pulses, which raise the question of their universality for the simplest case of the photoelectric effect. Here we investigate the photoionization of helium by a sequence of attosecond pulses in the presence of a weak infrared dressing field. We continuously control the energy and introduce an asymmetry in the emission direction of the photoelectrons, thus contradicting well established quantum-mechanical predictions. This control is possible due to an extreme temporal confinement of the light-matter interaction. Our work extends time-domain coherent control schemes to one of the fastest processes in nature, the photoelectric effect.