Development of an in situ peak intensity measurement method for ultraintense single shot laser-plasma experiments at the Sandia Z petawatt facility

Using the physical process of ultraintense field ionization of high charge states of inert gas ions, we have developed a method of peak intensity measurement at the focus of high energy short pulse lasers operating in single shot mode. The technique involves detecting ionization products created from a low pressure gas target at the laser focus via time of flight detector. The observation of high ion charge states collected by the detector yields peak intensity at the focus when compared with the results obtained from well established tunnel ionization models. An initial peak intensity measurement of 5×1016 W cm–2 was obtained for a 1.053 µm center wavelength, 0.4 J pulse with 1 ps pulse duration focused with an f/5.5 off-axis parabola. Experiments with multijoule level, 500 fs laser pulses are on the way.