A VERY CONVENIENT SETUP TO GENERATE INTENSE VUV COHERENT-LIGHT AT 125NM WITH USE OF NONLINEAR EFFECTS IN MERCURY-VAPOR AT ROOM-TEMPERATURE

Using only one dye laser, efficient generation of VUV radiation (10(13 ) photons/pulse) is demonstrated at 125.140 nm and 125.053 nm by four- wave sum-frequency mixing in a room-temperature mercury vapor. The emi ssion at 125.053 nm, which is out of two-photon resonance, but near th ree-photon resonance, has been observed for the first time and is care fully analyzed. In particular, numerical calculations have been carrie d out for Gaussian pump beams, taking into account absorption of VUV p hotons and optical Kerr effect. The results of the calculations reprod uce the VUV emission lineshape and power saturation effects measured i n the experiment.