Enhanced narrow spectral line and double electromagnetically induced two-photon transparency induced by double dark resonances
Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
Corresponding author: a email@example.com
Revised: 19 October 2006
Published online: 8 December 2006
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.
PACS: 42.50.Hz – Strong-field excitation of optical transitions in quantum systems; multiphoton processes; dynamic Stark shift / 42.50.Gy – Effects of atomic coherence on propagation, absorption, and amplification of light; electromagnetically induced transparency and absorption
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006