are seen, one at $-72.223$ MHz (outside the spectrum) and the other at $+156.943$ MHz (within the spectrum). The additional peak within the spectrum is due to atoms moving with a velocity of 52 m/s such that the probe drives the $F=1 \rightarrow F'=1$ transition and the pump drives the $F=1 \rightarrow F'=2$ transition. This spurious peak is more prominent compared to transitions starting from the upper ground level \[see Fig. \[satabs\](b)\] (though the real peaks still have high signal-to-noise ratio). The difference arises due to the fact that the closed transition for this set is the $F=1 \rightarrow F'=0$ transition, which has fewer magnetic sublevels in the excited state compared to the ground state. This leads to population trapping in the $m_F = \pm
1$ sublevels, and the relative importance of EIT effects in causing probe transparency (which is the same for all peaks) increases.

Spectrum in $^{85}$Rb, $F=3 \rightarrow F'=2,3,4$
-------------------------------------------------

The improvement with this technique is much more dramatic in the spectra of the other isotope, $^{85}$Rb. For transitions starting from the upper ground level ($F=3
\rightarrow F'=2,3,4$) shown in Fig. \[rb34\], the hyperfine peaks corresponding to $F'=2$ and 4 in the saturated-absorption spectrum are barely visible. 