Exploration of electromagnetically induced absorption with circular polarised lasers in a degenerate two-level system

The authors presented the corresponding measurements obtained with a modified version of our heterodyne interferometer. The measurement were obtained in the 6s 2S_1/2 F=4 rarr 6p ²P_3/2 F=5 transition of the caesium D₂ line. As it is the case for double linear polarisation the probe absorption signals showed electromagnetically induced absorption. However, the amplitude of the induced absorption peak over the broader regular absorption signal resulted much lower than the measured one for the double linear case. This may be due to the fact that in the double circular case no compact N subsystems can be easily built between the sublevels. The resulting spectra are therefore similar to those measured in open two-level systems.