Recoil-ion momentum spectroscopy of photoionization of cold rubidium atoms in a strong laser field

TL;DR

This study investigates the photoionization of cold rubidium atoms in strong laser fields using recoil ion momentum spectroscopy, revealing detailed momentum distributions and demonstrating high-resolution capabilities for studying electron correlations.

Contribution

The paper introduces a novel application of recoil ion momentum spectroscopy to cold rubidium atoms in various MOT configurations, providing detailed momentum profiles and high-resolution measurements.

Findings

Dipole-like double-peak momentum distribution observed

Momentum resolution of 0.12 ± 0.03 a.u. achieved

Results agree with strong field approximation calculations

Abstract

We study photoionization of cold rubidium atoms in a strong infrared laser field using a magneto-optical trap (MOT) recoil ion momentum spectrometer. Three types of cold rubidium target are provided, operating in two-dimension (2D) MOT, 2D molasses, and 3D MOT with densities in the orders of $10^7$ atoms/cm$^3$, $10^8$ atoms/cm$^3$, and $10^9$ atoms/cm$^3$, respectively. The density profile and the temperature of 3D MOT are characterized using the absorption imaging and photoionization. The momentum distributions of Rb$^+$ created by absorption of two- or three-photon illuminate a dipole-like double-peak structure, in good agreement with the results in the strong field approximation. The yielding momentum resolution of $0.12 \pm 0.03$ a.u. is achieved in comparison with theoretical calculations, exhibiting the great prospects for the study of electron correlations in alkali metal atoms through interaction with strong laser pulses.