Observation of CARS signal via maximal atomic coherence prepared by F-STIRAP in a three-level atomic system

We control the atomic coherence and the population transfer among Rb hyperfine atomic levels by the fractional stimulated Raman adiabatic passage (F-STIRAP) in a L-type configuration, and verify the theoretical predictions. Applying this technique, we are able to prepare the atoms with maximal coherence to enhance coherent anti-Stokes Raman scattering (CARS) signal. In our experiment by scanning the frequency of one laser from 794.9839 nm to 794.9844 nm with the 794.9698 nm laser frequency fixed to generate a maximum of the CARS signal we are able to obtain the energy level diagram of the sample.