Nearly Monochromatic Lasing at 182 Å in Neonlike Selenium

The $J=0\mathrm{}\to 1,3p\to 3s$ transition at 182 Å in neonlike selenium is observed to completely dominate the lasing output, as predicted but never observed before this work. Instead of a single long pulse we use a series of short 100 ps pulses from the Nova laser to illuminate slab targets of selenium. The 182 Å line is more than an order of magnitude brighter than the usual 206 and 209 Å laser lines. Similar behavior is observed for neonlike ions of germanium, zinc, and nickel.