Tunable coherent vacuum-ultraviolet generation in atomic vapors

Two tunable dye lasers have been used to generate coherent radiation at a tunable sum frequency in the vacuum-ultraviolet spectral region. Spectral ranges of ∼3500 cm⁻¹ around 1895 \AA{} and ∼1200 cm⁻¹ around 1798 \AA{} have been covered. These ranges may easily be extended. Large (∼×10⁴) enhancements of 2ν₁+ν₂ sum mixing are seen when 2ν₁ is tuned to a double-quantum allowed transition from the ground state in Sr vapor.