Enhancement of extreme ultraviolet emission from a laser-produced-lithium plasma by use of dual laser pulses

The use of dual laser pulses, a lithium plasma source produces unambiguously defined line emission at 13.5 nm with almost no off-band components, which minimize unnecessary heating of EUV optics. A plasma hydrodynamic calculation evaluated the plasma expansion time of 80 ns, within which the plasma density decreased to the critical density of the 1064-nm laser pulse.