Nonlinear magneto-optical resonances for systems with J~100 observed in K2 molecules M. Auzinsh, R. Ferber, I. Fescenko, L. Kalvans, M. Tamanis Laser Centre, The University of Latvia Iļja Feščenko Rīga, 05.10.2011

Creation and destruction of atomic coherence z Je =1 B s- s+ s- y s+ Jg =1 x Introduction Experiment Theory Results Discussions Conclusion

Hanle effect and configuration Je =1 s+ s- Jg =1 M=-1 M=0 M=+1 Introduction Experiment Theory Results Discussions Conclusion

Magneto-optical effects Applications: opto-electronics, medicine, precise measurement techniques, magnetometry... Manifestations: dark and bright resonances, coherent population trapping, electromagnetically induced transparency, electromagnetically induced absorption, slow light etc. Introduction Experiment Theory Results Discussions Conclusion

Diatomic molecules History: Motivation: First report in 1972 for the I2 molecule, analysis using the classical treatment in terms of the balance equations for the classical probability density, in 1976. First direct experimental studies in 1979 for the potassium and sodium, A model was developed in 1988, applied an expansion of the density matrix via polarization (multipole) moments Motivation: to revisit the nonlinear ground state Hanle effect of a diatomic molecule with J~100, to apply the detailed theoretical treatment, to study in detail the peculiarities observed in earlier works. Introduction Experiment Theory Results Discussions Conclusion

Cell to vacuum system Introduction Experiment Theory Results Discussions Conclusion

K2 molecules X1Sg+(2,99)→ B1Pu(0,99) X1Sg+(2,105)→ B1Pu(0,106) Excitation Registration X1Sg+(2,99)→ B1Pu(0,99) X1Sg+(2,105)→ B1Pu(0,106) Introduction Experiment Theory Results Discussions Conclusion

Set-up Introduction Experiment Theory Results Discussions Conclusion Polarizer λ/2 Diode Laser Power supply Monochromator PMT Lens Magnet Coils Introduction Experiment Theory Results Discussions Conclusion

Theoretical model   Introduction Experiment Theory Results Discussions Conclusion

Calculations     Introduction Experiment Theory Results Discussions Conclusion

Dependence on atomic density Introduction Experiment Theory Results Discussions Conclusion

Dependence on laser power density Introduction Experiment Theory Results Discussions Conclusion

Q and R excitation Introduction Experiment Theory Results Discussions Conclusion

Dependence on laser power density WR =27 WR =10 Introduction Experiment Theory Results Discussions Conclusion

Rabi frequency Introduction Experiment Theory Results Discussions Conclusion

Multipole moments MJ DM = 2 MJ DM = 4 g= 2wL g= 4wL Introduction Experiment Theory Results Discussions Conclusion

Summary Introduction Experiment Theory Results Discussions Conclusion Nonlinear magneto-optical resonances have been studied for systems with large angular momentum (J~100) in K2 molecules. Dark resonances have been theoretically predicted and experimentally detected. Bright resonances were neither detected nor predicted by the theoretical model for such a system. We explained the narrow maximum previously observed in the degree of LIF polarization in earlier works. It was demonstrated that it is possible to describe nonlinear magneto-optical resonances in systems with large angular momenta over a wide range of experimental conditions with the theoretical model. As a result, theoretical modeling can serve as a tool for future investigations of systems with large angular momenta and for the development of practical applications based on them. Introduction Experiment Theory Results Discussions Conclusion