Multiple ionisation of rare-gas atoms by an intense CO₂laser (10¹⁴W cm^-2)

Abstract

The authors present results of an experiment in which isolated atoms of five rare gases were ionised by an extremely intense CO2 laser pulse (1014 W cm-2). The results are in the form of plots of ion numbers against laser intensity. These are shown for each gas and at two different arbitrary wavelengths. The authors observed up to triply charged ions, and analysis indicates that these are formed through a step-wise process, involving the absorption of at least 500 photons for energy conservation. They also show that the interactions are highly non-linear.