This project bridges three traditionally separated research areas: molecular spectroscopy, quantum optics and coherent control. The frequency domain quantum control tool used here differs from the time domain control schemes used in coherent control. Recently this tool has been used to demonstrate molecular angular momentum control and to measure with high accuracy the absolute magnitude of the molecular transition dipole moment matrix element, which plays a critical role in absorption and emission of light by molecules. The goal of this project is to develop molecular dynamics applications for the frequency domain control scheme. In addition to the ongoing research on quantum control, this project will attempt control of pre-dissociation of molecules, and study the role of valence electron spin in reactive collisions. This project also involves research on molecular structure of interest for ultracold molecular physics. The frequency domain control scheme, combined with a four color excitation scheme, can be used for state selective transfer of molecular population to the lowest vibrational levels of the electronic ground state, a process that is critical for applications involving ultracold molecules in optical lattices. In addition, the project includes an experimental determination of the triplet ground state and first excited states potentials of alkali dimers. These data will be important for research on ultracold molecule formation.
Broader impacts include the connection with work on ultracold molecules and providing research opportunities and mentoring for students in molecular quantum optics. The project will also continue to contribute strongly to broadening the participation of underrepresented students, both graduate and undergraduate.
Our research on Molecular Quantum Optics during this award period was featured as a Chapter in Advances in Atomic, Molecular, and Optical Physics, Vol.61 in 2012 [ref.1]. Following our work on enhancing quantum state selectivity in molecular dynamics experiments to magnetic sublevels through angular momentum alignment control [ref. 2], mapping the absolute magnitude of vibrationally averaged transition dipole moment matrix elements [ref. 3] as a function internuclear distance [refs. 4–6], we have demonstrated during this award period control of quantum state electron spin multiplicity character. When the two valence electrons of a diatomic molecule have parallel spins, the resulting electronic state is a triplet state and when the valence electron spins are anti-parallel, the resulting bond corresponds to a singlet electronic state. We have demonstrated that the electric field of a control laser can be used as the control mechanism to enhance the natural spin–orbit interaction of a singlet and triplet pair of rovibrational levels [ref. 7]. Such control of the spin multiplicity of molecular ro-vibrational levels is of interest for the transfer of population from the triplet ground state to the absolute lowest energy vibrational and rotational level of the singlet ground state [refs. 8–11]. Since the population transfer of molecules formed in a triplet state to a singlet state involves a forbidden singlet–triplet transition, this frequency domain singlet–triplet quantum state spin multiplicity control mechanism can play an important role in this context by effectively making this forbidden transition less forbidden. During this award period we have also demonstrated Electromagnetically Induced Transparency in Λ- and V- type excitation systems. In addition, we have published a number of papers on high resolution spectroscopy of alkali dimer molecules of critical interest to the ultracold molecular Physics community. These results include the potential energy function of the triplet ground states of the Rubidium (J. Chem. Phys., 094505,1- 6, (2009), and he Cesium (J. Chem. Phys, 130, 051102 (2009) dimer molecules and the energy level data and de-perturbation analysis of the first excited states of these molecules (Rb2: Phys. Rev.A, 80, 022515 (2009) and Cs2: Phys. Rev. A 83, 032514 (2011). In terms of broader impact and human resource development, three female students graduated with PhD's with support from this award. 1. E. H. Ahmed, J. Huennekens, T. Kirova, J. B. Qi, and A. M. Lyyra, in Advances in Atomic, Molecular, and Optical Physics, Vol 61, edited by E. Arimondo, P. R. Berman, and C. C. Lin (Elsevier Academic Press Inc, San Diego, 2012), Vol. 61, pp. 467. 2 J. B. Qi, G. Lazarov, X. J. Wang, L. Li, L. M. Narducci, A. M. Lyyra, and F. C. Spano, Phys. Rev. Lett. 83 (2), 288 (1999). 3 E. Ahmed, A. Hansson, P. Qi, T. Kirova, A. Lazoudis, S. Kotochigova, A. M. Lyyra, L. Li, J. Qi, and S. Magnier, J. Chem. Phys. 124 (8) (2006). 4 E. H. Ahmed, P. Qi, B. Beser, J. Bai, R. W. Field, J. P. Huennekens, and A. M. Lyyra, Phys. Rev. A 77 (5) (2008). 5 S. J. Sweeney, E. H. Ahmed, P. Qi, T. Kirova, A. M. Lyyra, and J. Huennekens, J. Chem. Phys. 129 (15) (2008). 6 O. Salihoglu, P. Qi, E. H. Ahmed, S. Kotochigova, S. Magnier, and A. M. Lyyra, J. Chem. Phys. 129 (17) (2008). 7 E. H. Ahmed, S. Ingram, T. Kirova, O. Salihoglu, J. Huennekens, J. Qi, Y. Guan, and A. M. Lyyra, Phys. Rev. Lett. 107 (16) (2011). 8 F. Lang, K. Winkler, C. Strauss, R. Grimm, and J. H. Denschlag, Phys. Rev. Lett. 101 (13) (2008). 9 D. DeMille and E. R. Hudson, Nat. Phys. 4 (12), 911 (2008). 10 S. Knoop, M. Mark, F. Ferlaino, J. G. Danzl, T. Kraemer, H. C. Nagerl, and R. Grimm, Phys. Rev. Lett. 100 (8) (2008). 11 A. Chotia, B. Neyenhuis, S. A. Moses, B. Yan, J. P. Covey, M. Foss-Feig, A. M. Rey, D. S. Jin, and J. Ye, Phys. Rev. Lett. 108 (8) (2012).