Coherence phenomena in laser-atom interactions have been a focus of interest for decades. However, due to the small size of typical molecular transition moments, the field of coherence effects in laser-molecule interactions is closer to its infancy. In addition, unlike atoms, even the simplest molecules are open systems, in that every excited molecular ro-vibrational level is radiatively coupled to many more energy levels than in the case of any excited atomic state. Therefore, molecules – with their rich excitation pathways and the variety of molecular interactions – make attractive candidates in the development of novel and powerful applications in this field.
By utilizing narrowband, continuous wave (CW) lasers and appropriately filtered laser induced fluorescence (LIF), we have benefitted from the high resolution techniques of multiple resonance laser spectroscopy.
Prof. Marjatta Lyyra co-pioneered continuous wave triple resonance spectroscopy with initial applications in high resolution molecular spectroscopy of electronic states involving large internuclear distance in collaboration with Profs. William C. Stwalley and Paul D. Kleiber at the University of Iowa. At Temple University, her research group has used this technique in molecular quantum optics studies by using the Autler-Townes (AT) effect to demonstrate molecular Electromagnetically Induced Transparency (EIT) and more recently with Prof. Ergin H. Ahmed all-optical control of molecular angular momentum orientation by state selective population of individual magnetic sublevels. We have also shown that the Autler-Townes effect can be used as a precision probe of the molecular transition dipole moment and its internuclear distance dependence. And we’ve more recently demonstrated all-optical control of molecular population flow through a pair of singlet-triplet levels perturbed by the spin-orbit interaction. Research on optimizing this process by the development of an all-optical spin switch is planned.
News (recent):
09/22-23/2025: our group hosts Prof. Dr. Yu Liu and two of his graduate students, Jingchen Zhang and Jiarui (“Jerry”) Yu, from the University of Maryland to discuss Li2 molecules in the context of quantum controlled isotope exchange reaction chemistry and to potentially establish a long-term collaboration. Group photo
08/04-27/2025: our group hosts Prof. Dr. Johannes Hecker Denschlag, director of the Institute of Quantum Matter at the University of Ulm to discuss Rb2 molecules in the context of quantum controlled state-to-state chemistry and to potentially establish an international collaboration.
03/30-04/04/2025: our group hosts Dr. Robert W. Field (MIT), inventor of Stimulated Emission Pumping and author of The Spectra and Dynamics of Diatomic Molecules, to discuss molecular spectroscopy.
09/16-10/14/2024: our group hosts Dr. Ennio Arimando and Dr. Maria Allegrini from University of Pisa, Italy as part of the QDYNAMO project to discuss quantum optics based quantum control for creating orientation in molecules.
09/01-10/31/2024: our group hosts Dr. Rita Veilande, head of the Laboratory of Theoretical Physics at the Institute of Atomic Physics and Spectroscopy, University of Latvia for the QDYNAMO project.