Comment on arXiv:1105.6334 "Optical nonlinearity in Ar and N$_2$ near the ionization threshold"

TL;DR

This paper reanalyzes Wahlstrand et al.'s experimental data and finds evidence of a 22% saturation indicating the presence of the higher-order Kerr effect, challenging their original conclusions.

Contribution

It provides a careful reanalysis of existing experimental data, revealing evidence of the higher-order Kerr effect that was previously unreported.

Findings

Revealed 22% saturation in original data

Provided direct proof for higher-order Kerr effect

Questioned the validity of prior conclusions

Abstract

In a recent publication [Phys. Rev. Lett. 107, 103901 (2011)], Wahlstrand et al. reported to observe no indications for the appearance of the higher-order Kerr effect in a parameter regime that was previously found to display this phenomenon [Opt. Express 17, 13429 (2009)]. Here we show that careful analysis of the original experimental data of Wahlstrand et al. reveals a 22% saturation, i.e., direct proof for the appearance of the higher-order Kerr effect. In the light of these findings, the validity of Wahlstrand et al.'s main conclusions appears highly questionable.