Fine Structures of Laser-Driven Punched-Out Tin Fuels Observed with Extreme Ultraviolet Backlight Imaging

The laser-driven punched-out scheme, which has been proposed for supplying minimum-mass tin fuels at a high repetition rate, was investigated for use in an extreme ultraviolet (EUV) light source. The density profile of punched-out tin fuel is a critical parameter for validating applicability of this scheme. An EUV backlight technique was developed to measure the density profile and fine structure. Experimental results reveal that a punched-out target does not remain its initial thin shape, but expands into a rarefied gas and liquid and small particles under the present target and laser conditions.