Nonlinear generation of 104.8-nm radiation within an absorption window in zinc

Two autoionizing levels which are separated by a few decay widths may exhibit a sharp interference or window in their absorption profile and also make canceling contributions to the refractive index at the absorption minimum. A correct choice of intermediate mixing levels prevents a similar cancellation in the nonlinear susceptibility. Using uv lasers with energies of about a mJ and pulse lengths of 5 ns, we generate 0.23 {μ}J per pulse at 104.8 nm.