Laser-plasma-induced extreme-ultraviolet radiation from liquid mercury

Extreme ultraviolet (XUV) radiation from 100 to less than 30 nm is emitted from a laser-induced plasma generated on a liquid-mercury surface. This surface does not degrade even after tens of thousands of laser pulses. The 532-nm laser light focused on the mercury forms a bright plasma core and a plume extending several millimeters above the liquid level. The plasma core produces primarily continuum radiation, whereas the plume emits lines at wavelengths above 77 nm. The mercury plasma was generated at the entrance port of a normal incidence vacuum monochromator, and the dispersed XUV radiation was monitored with a photomultiplier tube.