Abstract

Four-wave mixing (FWM) in gaseous media has successfully been employed for the generation of intense tunable coherent vacuum ultraviolet radiation below ~200 nm.¹) Although rare gases are the most convenient nonlinear materials, in the extreme ultraviolet (XUV) spectral region less than about 100 nm, only a few experiments^2,3) have so far been reported using two-photon resonances which greatly enhance the nonlinear susceptibilities and resulting conversion efficiency. Here we report the generation of tunable coherent XUV radiation by two-photon resonant FWM in Kr and Xe, where the recently-developed new nonlinear crystal β-BaB₂C₄ (BBO)^4-6) has been used to produce the fundamental deep UV radiation required for the two-photon resonances.

© 1988 Optical Society of America