TIME-DEPENDENT EFFECTS IN NONLINEAR GENERATION OF VUV RADIATION WITH INDUCED TRANSPARENCY

The generation of coherent radiation at 102.6 nm in atomic hydrogen by nonlinear mixing with electromagnetically induced transparency has be en investigated experimentally in the low-density limit, for compariso n with theory. Intense laser pulses of 243 nm radiation, in two-photon resonance with the 2s level, and of 656 nm radiation, for strong coup ling of the 2s and 3p levels were incident on the medium. While the ob served results were in general agreement with steady-state theory, det ailed comparison revealed the need to include intensity effects such a s population transfer and ionization, and the time dependence of varyi ng Rabi couplings and upper-state lifetimes. Photoion generation, used as a probe of induced transparency, was also analyzed by time-depende nt theory.