Controlling absorption of gamma radiation via nuclear level anticrossing.

A significant reduction of absorption for single gamma photons has been experimentally observed by studying Mössbauer spectra of 57Fe in a FeCO3 crystal. The experimental results have been explained in terms of a quantum interference effect involving nuclear level anticrossing due to the presence of a combined magnetic dipole and electric quadrupole interaction.

Transporting and time reversing light via atomic coherence.

We study basic issues central to the storage of quantum information in a coherently prepared atomic medium such as the role of adiabaticity. We also propose and demonstrate transporting, multiplexing, and time reversing of stored light.

Stopping light via hot atoms.

We prove that it is possible to freeze a light pulse (i.e., to bring it to a full stop) or even to make its group velocity negative in a coherently driven Doppler broadened atomic medium via electromagnetically induced transparency (EIT). This remarkable phenomenon of the ultraslow EIT polariton is based on the spatial dispersion of the refraction index n(omega,k), i.e., its wave number dependence, which is due to atomic motion and provides a negative contribution to the group velocity. This is related to, but qualitatively different from, the recently observed light slowing caused by large temporal (frequency) dispersion.

Mixed electromagnetically and self-induced transparency.

We show that application of self-induced transparency (SIT) solitons as a driving field in V-type electromagnetically induced transparency (EIT) leads to ;;mixed induced transparency' (MIT) that nicely combines the best features of both SIT and EIT.