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 mixture. When the laser amplitude is increased, the slope in the quasistatic wing changes, the spectral peak reaches saturation, and the spectral line shape loses asymmetry. These features are in fair to good agreement with predictions of existing theoretical models. However, no appreciable shift of the spectral peak was observed at intensities ranging from 23 MW/cm up to 3.75 GW/cm, in contrast with the predictions of those models.