THE INFLUENCE OF A 2ND RESONANCE ON THE SATURATION CHARACTERISTICS OFTHE 4-WAVE SUM MIXING

Experimental results are presented, related to the saturation mechanis ms of the four-wave sum mixing (4-WSM) generation in Hg when a double resonance enhancement is employed, that is, a two photon resonance to the 8(1)S(0) state followed by the 8(1)S(0)-6p'D-3(1) one photon coupl ing. This coupling is shown to alter the saturation characteristics of the four-wave sum mixing radiation by affecting the two-photon excita tion to the 8(1)S(0) state, reduce the ionization of the Hg atoms by t he incoming radiation and create an absorption window for the generate d radiation in a region near the autoionizing state by modifying the l inear susceptibility.