Figure 2
From: Robust Population Inversion by Polarization Selective Pulsed Excitation
Schematic representation of double pulse excitation using co-polarized laser pulses with constructive phasing (a) and cross-polarized pulses (b). The pulse areas for the consecutive pulses are equal. Raising the total pulse area of both pulses (c) leads for the co-polarized case to Rabi oscillations (experiment: red dots; theory: red solid line). Sufficient degrees of inversion can only be obtained in narrow regions around 1π and 3π. Cross-polarized excitation (shown in blue) offers robust inversion with a flat gradient for a considerably wider range of pulse areas around 2π.
