Tunable extreme-ultraviolet radiation from 105 to 87.5 nm using Hg vapor.

Tunable, coherent radiation has been generated in the region 105 to 87.5 nm by resonant four-wave frequency mixing in Hg vapor. A glass capillary array forms an efficient XUV window with 50% transmission. An absorption spectrum of N(2) was recorded at 89 nm with a resolving power of 2 x 10(5).