BROADLY TUNABLE VACUUM-ULTRAVIOLET RADIATION SOURCE EMPLOYING RESONANT ENHANCED SUM DIFFERENCE FREQUENCY MIXING IN KRYPTON

Vacuum-ultraviolet (VUV) generation by resonant third-order sum-difference frequency conversion (wvuv = 2WR − Wr) in krypton has been investigated. The frequency WR (λR = 212.55 nm) was resonant with the Kr two-photon transition 4p-5p[1/2, 0]. By tuning WT in the range λT = 220-860 nm it was possible to generate wvuv in the wavelength range λvuv = 200-120 nm. The conversion efficiency was enhanced in the range 121-123 nm by phase matching with a normally dispersive buffer gas (Ar); under the best phase-matched conditions employed, VUV output powers at the Lyman-a wavelength of the order of 1 kW were inferred from the estimated VUV pulse energy. This source was used to measure high-lying members of the Mg principal series near 162 nm. High resolution and excellent sensitivity of detection, when a thermionic diode detector was used, have been demonstrated. © 1990 Optical Society of America.