Fourier-transform-limited extreme-ultraviolet (XUV) radiation (bandwidth < or approximately MHz) tunable around 91 nm is produced by use of two-photon resonance-enhanced four-wave mixing on the Kr resonance at 94093 cm^-1. Noncollinear phase matching ensures the generation of an XUV sum frequency 2omega_1 + omega_2 that can be filtered from auxiliary laser beams and harmonics by an adjustable slit. Application of the generated XUV light is demonstrated in spectroscopic investigations of highly excited states in H2 and N2.
© 2005 Optical Society of America
S. Hannemann, U. Hollenstein, E.-J. van Duijn, and W. Ubachs, "Production of narrowband tunable extreme-ultraviolet radiation by noncollinear resonance-enhanced four-wave mixing," Opt. Lett. 30, 1494-1496 (2005)