New source for tuning the effective Rabi frequency discovered in multiphoton ionization

TL;DR

This paper investigates the Autler-Townes effect in potassium atoms during multiphoton ionization, revealing a new method to tune the effective Rabi frequency by accounting for ionization effects.

Contribution

It introduces an effective Rabi frequency formula that includes ionization, enabling better control of coupling strength in atomic systems.

Findings

Effective Rabi frequency matches calculations at low intensities

Deviations occur at high laser intensities above 1.5x10^11 W/cm^2

Ionization effects significantly influence the Rabi frequency tuning

Abstract

The Autler-Townes effect due to near resonance transition between 4s-4p states in potassium atoms is mapped out in the photo-electron-momentum distribution and manifests itself as a splitting in the photo-electron kinetic energy spectra. The energy splitting fits well with the calculated Rabi frequency at low laser intensities and shows clear deviation at laser intensities above 1.5x10^11 W/cm^2. An effective Rabi frequency formulae including the ionization process explains the observed results. Our results reveal the possibility to tune the effective coupling strength with the cost of the number of level-populations.