EXPERIMENTAL-EVIDENCE OF STRONG-FIELD EFFECTS IN LIGHT-INDUCED COLLISIONAL ENERGY-TRANSFER PROCESSES IN EUROPIUM AND STRONTIUM ATOMS

Strong-field effects in the light-induced collisional energy-transfer spectral profile were investigated for the europium-strontium binary m ixture. When the laser amplitude is increased, the slope in the quasis tatic wing changes, the spectral peak reaches saturation, and the spec tral line shape loses asymmetry. These features are in fair to good ag reement with predictions of existing theoretical models. However, no a ppreciable shift of the spectral peak was observed at intensities rang ing from 23 MW/cm2 up to 3.75 GW/cm2, in contrast with the predictions of those models.