Recently observed dark resonance phenomena is solids are reviewed and discussed for potential applications to high-resolution coherence spectroscopy. in an inhomogeneously broadened system, a new type of high-resolution spectroscopy based on electromagnetically induced transparency is demonstrated.
Summary form only given. The phenomenon of "dark resonances" or coherent population trapping is a well known concept in optics and laser spectroscopy. It can be considered as the basis for such effects as electromagnetically induced transparency and lasing without inversion. We report the observation of the novel spectral features which arise in systems where multiple quantum superposition states are coupled and interact coherently. These novel resonances correspond to the recently predicted "double-dark states". In the experiment, an optically thin ensemble of rubidium-37 atoms in zero magnetic field is excited in a /spl Lambda/ configuration with circularly polarized light from a pair of 789 nm diode lasers.
Single particle spectroscopy has become a source of valuable information on fundamental interactions between light and matter. Whereas trapping and cooling of ions and atoms has been sucessfully achieved, single molecules, because of their multilevel structure (high number of internal degrees of freedom) have not been observed in electromagnetic traps so far. However due to the presence of zero phonon lines in conjunction with inhomogeneous broadening the spectroscopic isolation and detection of single molecules ‘trapped in solids at very low temperatures' is made feasible [1,2]. Single molecule spectroscopy allows to study the distribution of molecular properties and not only the statistical average which is generally observed.
Summary form only given. Experiments in nonlinear optics and spectroscopy are often performed in atomic vapors, where the linewidths of the transitions of interest are dominated by Doppler broadening. In fact, several experiments on quantum coherent phenomena, such as lasing without inversion (LWI), and electromagnetically induced transparency (EIT), have been done in atomic vapors. Using the ideas of quantum coherence and interference, we propose a new scheme for obtaining subDoppler resolution at one transition of an inhomogeneously broadened, three-level atomic system, by use of an intense control field at the other transition.