Laser enhancement of the collisional broadening of the 4713 and 3188 AA lines in a helium plasma

Abstract

The enhancement of the electron collisional broadening of the 4s3S1 and 4p3P2,1,0 degrees levels in a helium glow discharge (ne=1013-1014 cm-3), induced by the non-resonant interaction of the 4s3S1 and 4p3P2,1,0 degrees levels with a CO2 laser field, is reported. This extra broadening depends on the product of the electron density with the laser field amplitude and manifests itself on the 4713 and 3188 AA linewidths (the transitions 4s3S1 to 2p3P2,1,0 degrees and 4p3P2,1,0 degrees to 2s3S1 respectively). This effect results from the destruction, by electronic collisions, of the coherence induced by the laser field between the 4s3S1 and 4p3P2,1,0 degrees levels, and can be viewed as an electron-atom collisional fluorescence redistribution process at relatively large laser detuning.