Abstract:

The authors presented the experimental observations and theoretical calculations of double electromagnetically induced transparency (EIT) windows in a four-level inverted\|Y atomic system. The results show that the locations of two EIT windows can be controlled by manipulating the parameters of the two coupled fields.  The physical mechanism of double EIT is double dark resonances induced by the two coupled fields simultaneously interacting with the atomic system. The sub\|Doppler spectral resolution in the center of the absorption spectrum is induced due to the interaction between double dark resonances. A narrow absorption peak with a width of 30 MHz is obtained in the experiment.

Key words: double electromagnetically induced transparency (EIT), sub\, Doppler absorption spectrum, double dark resonances