Focused laser intensity measurement at 10(18) W/cm(2) and 1053 nm

We present a simple experimental setup that makes possible the measurement of the beam section at focus under full-power conditions. We demonstrate that a 1.5-TW laser system can be focused down to a 13.5-microm-diameter spot using conventional lens focalization, thus achieving laser intensities of up to 10(18) W/cm(2).