Off-resonant transition rate measurement

This is an energy level of 87Rb atoms. The F=2 to F'=3 transition is dipole allowed and separated from the other dipole allowed energy levels. However, the existance of the hyperfine structure causes an off-resonance transition to F=1 state during the optical resonance from F=2 to F'=3 state. This off-resonant transition rate is measured using the following technique.
Step from left to right in the next table. Before measurement,there is no repumping pulse injection in pattern A, and there is a repumping pulse in pattern B. In pattern A only F=2 state atoms are resonant to the absorption measurement, and in patternB, F=1 state atoms are repumped to the F=2 state, both F=1 and F=2 state atoms are measured.

MOT molasses dark molasses No pre-pump
Pattern A
Absorption measurement
MOT molasses dark molasses Pre-pump ON
Pattern B
Absorption measurement

Using this technique, the F=1state and F=2 state atoms are easily separated as the following figure 1. Changing the duration length of the dark molasses period and changing the intensity of the F=2 to F'=3 laser light, the next Fig.2 is got. This graph represents the off-resonant transition rate to F=1 at different laser intensities.

Fig.1 : F=1 & F=2 separation

Fig.2 : Off-resonant transition rate

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