Multi-photon electron emission with non-classical light

TL;DR

This study investigates how different photon quantum statistics of ultrashort light pulses influence electron emission from metal tips, revealing that photon statistics significantly affect electron distributions and can be tailored for advanced quantum applications.

Contribution

It demonstrates the direct imprint of photon quantum statistics on electron emission distributions and introduces methods to tailor these distributions using non-classical light sources.

Findings

Electron distributions change substantially with photon statistics.

Extreme electron emission events occur with non-classical light, up to 65 electrons per pulse.

Photon statistics can be tailored by adjusting the modes of the light source.

Abstract

Photon number distributions from classical and non-classical light sources have been studied extensively, yet their impact on photoemission processes is largely unexplored. In this article, we present measurements of electron number-distributions from metal needle tips illuminated with ultrashort light pulses of different photon quantum statistics. By varying the photon statistics of the exciting light field between classical (Poissonian) and quantum (super-Poissonian), we demonstrate that the measured electron distributions are changed substantially. Using single-mode bright squeezed vacuum light, we measure extreme statistics events with up to 65 electrons from one light pulse at a mean of 0.27 electrons per pulse - the likelihood for such an event equals $10^{-128}$ with Poissonian statistics. Changing the number of modes of the exciting bright squeezed vacuum light, we can tailor the electron-number distribution on demand. Most importantly, our results demonstrate that the photon statistics is imprinted from the driving light to the emitted electrons, opening the door to new sensor devices and to strong-field quantum optics with quantum light.