Demonstration of a 10-Hz, 41.8 nm laser

We have observed lasing in Xe/sup 8+/ XUV ion lasers operating by collisional excitation that required solid density targets and pump laser pulse energies of several hundred joules, a 10 Hz, 800-nm laser pulse with an energy of -70 mJ and time duration of -40 fs is longitudinally focused in a differentially pumped cell containing 5 to 12 ton: of Xe gas.