INVESTIGATION OF VACUUM-ULTRAVIOLET GENERATION IN A RESONANT 4-WAVE-MIXING SCHEME IN KRYPTON WITH ELECTROMAGNETICALLY INDUCED TRANSPARENCY

We report experiments investigating a resonant sum-difference frequenc y mixing scheme in krypton producing coherent radiation at 123.6 nm (i .e. in the vacuum ultraviolet (VUV)). Owing to the resonant nature of this scheme, electromagnetically induced transparency (EIT) plays a cr ucial role in the generation of this coherent radiation, resulting in a greatly enhanced conversion efficiency. This is the first time a res onant sum-difference mixing scheme involving EIT, that generates VUV r adiation, has been investigated experimentally. Our results are in bro ad agreement with theoretical predictions. Measurements are presented of the dependence of VUV generation on laser detuning (in the range +/ -3 cm(-1)) and laser powers. In particular the dependence on the coupl ing field strength has been studied in the range of coupling held Rabi frequencies Omega(c) = 0.05-3 cm(-1). We estimate an enhancement in t he conversion efficiency, compared with the non-resonant case, of grea ter than 10(2).