Partitioning of the linear photon momentum in multiphoton ionization

TL;DR

This study experimentally investigates how linear photon momentum is distributed during multiphoton ionization of argon and neon atoms using circularly polarized laser pulses, revealing that photoelectrons carry momentum consistent with absorbed photons.

Contribution

It provides the first experimental evidence linking photon momentum to photoelectrons in multiphoton ionization at specific wavelengths and intensities.

Findings

Photoelectrons carry momentum corresponding to absorbed photons.

Momentum transfer occurs above the field-free ionization threshold.

Implications for terahertz radiation generation models.

Abstract

The balance of the linear photon momentum in multiphoton ionization is studied experimentally. In the experiment argon and neon atoms are singly ionized by circularly polarized laser pulses with a wavelength of 800 nm and 1400 nm in the intensity range of 10^{14} - 10^{15} W/cm^2. The photoelectrons are measured using velocity map imaging. We find that the photoelectrons carry linear momentum corresponding to the photons absorbed above the field free ionization threshold. Our finding has implications for concurrent models of the generation of terahertz radiation in filaments.