Nonlinear generation of Lyman-alpha radiation

Tunable narrow-band Lyman-alpha radiation (∼1216 Å) has been generated by frequency tripling in krypton. A near-diffraction-limited tunable 15-nsec 10-MW input at 3648 Å was used to generate ∼3.6×1011 photons (60 W) per pulse at 1216 Å. Measurements of the output as a function of gas pressure give the refractive index for krypton at 1216 Å, demonstrating its negatively dispersive character.