Recombination laser in the exploding-type-pumping using a 30-nm thin membrane target

Abstract
In order to increase the gain length product for the [MATH] line (13.4 nm) of hydrogen-like Nitrogen in the "exploding type pumping" of irradiating a 30 nm thick SiN membrane target with a few ps pulse, the pumping laser system is up-graded. For crucially important issue of suppressing a pre-pulse, the energy of the front-end of the pumping laser system was increased by one order. Beam pattern of the pumping laser pulse on the vacuum chamber window was improved with an image relay. In order to start experiments of a water-window laser, chirping pulse amplification in e-beam pumped KrF laser system is planned.