Enhanced narrow spectral line and double electromagnetically induced two-photon transparency induced by double dark resonances

The European Physical Journal D (Impact Factor: 1.23). 02/2007; 41(3):563-569. DOI: 10.1140/epjd/e2006-00258-0


We theoretically investigate the features of two-photon absorption
in a five-level atomic system with interacting dark resonances. It
is found that two-photon absorption can be completely suppressed
at two different frequencies due to the application of two
coherent coupling fields and the atomic system exhibits double
electromagnetically induced transparency windows against
two-photon absorption. The position and width of the double
two-photon transparency windows can be controlled via properly
adjusting the frequency detuning and the intensities of the two
coupling fields. In addition, one enhanced narrow central line can
be observed in the two-photon absorption spectra, which may find
applications in high-precision spectroscopy. Form a physical point
of view, we explicitly explain these results in terms of quantum
interference induced by three different two-photon excitation
channels in the dressed-state picture.

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Available from: Xiaoxue Yang, Dec 19, 2013