The concept of quantum coherence has been exploited in a wide variety of media, including Bose condensates, laser cooled gases, low temperature solid crystals, and room temperature gases. In this talk, I will describe experiments we are currently performing that use quantum coherence in novel settings. The first experiment involves a room temperature cell of rubidium with long ground state relaxation time, but, in contrast to previous experiments, we employ counter-propagating beams. The spectra show novel sub-natural line width features. The second experiment involves the measurement of non-linear polarization rotation in laser cooled sodium atoms and we will demonstrate sub-natural linewidth features as well.

Contact: Luis A. Orozco.