Absorption Spectrum: Excited State Hyperfine Structure

When the pump beam was no longer blocked and could pass through the Rb cell along with the probe beam, the excited state hyperfine peaks in the absorption spectrum could be observed. The spectrum is shown below.

The four major peaks that appeared with just the probe beam are still visible. However, within each major peak up to three smaller peaks appear. This is due to the fact that with the Lamb Dip apparatus, we are able to see the transitions to the two separate levels of the 5p_1/2 level (as shown below).

The frequency difference between the levels in the excited state hyperfine structure for ⁸⁷Rb is 1000 MHz from the graph. This compares to a reported value of 818.2 MHz for the frequency difference between the levels in the excited state hyperfine structure for ⁸⁷Rb. The frequency difference between the levels in the excited state hyperfine structure for ⁸⁵Rb is 500 MHz from the graph. This compares to a reported value of 362.1 MHz for the frequency difference between the levels in the excited state hyperfine structure for ⁸⁵Rb. ²

Click here to return to the Table of Contents.