Vacuum ultraviolet picosecond pulse generation using cw mode-locked dye lasers

We report the generation of a continuous train of pulses of ∼5-psec duration with wavelength tunable near 1700 Å using two synchronously mode-locked cw dye lasers. Two-photon resonantly enhanced 4-wave mixing in Sr vapor was employed to obtain approximately 10−10 W average power (∼10−7 W/pulse) for inputs of less than 5 mW. The efficiency of this process was measured and is quantitatively compared to previous vacuum ultraviolet coherent radiation generation schemes in Sr vapor.