1202.8-Å generation in Hg using a parametrically amplified dye laser

We have generated 1202.8-Å radiation, one-half the frequency of the
1s^{1} S_{o}-2s^{1}S_{o}
forbidden transition in He, using resonantly enhanced four-wave optical mixing in Hg vapor. Peak powers of 300 W in a ∼ 15-ps pulse have been achieved using a tunable narrow-band source consisting of a parametrically amplified commercial dye laser. The dependence of the conversion efficiency on the spectral properties of this source is described. Hg is shown to be negatively dispersive for this process, and thus phase matchable.