1. Collisional Orientation Transfer Facilitated Polarization Spectroscopy Jianmei Bai, E. H. Ahmed, B. Beser, Yafei Guan, and A. M. Lyyra Temple University S. Ashman, C. M. Wolfe, and J. Huennekens Lehigh University Funded by NSF PHY 0555608, PHY 0855502, PHY 0652938 and PHY 0968898. 1

2. Motivation The A~b mixed states of Rb 2 and Cs 2 are important in the creation of ground state ultracold molecules. Missing data in the gap region is a problem for global deperturbation analysis of the A~b complex. We use polarization spectroscopy to cover the gap region. Cs 2 Gap in the previous rotational energy level data of Cs 2 A~b states 2

3. Anisotropic Magnetic Sublevel Population Created by the Pump Laser (a) M=-10+1 J=1 ∆M=+1 Molecular Sample M=-2 0+1 J=2 Pump WaveProbe Wave (b) (a) Level scheme for a P transition J=2 J=1 (b) Linearly polarized probe beam and circularly polarized pump beam The magnetic sublevel populations become anisotropic +2 3

4. Change of the Polarization Direction 4

5. Profile of the Polarization Signal neglected background dispersion Lorentzian 5

6. Ti-Sapphire Laser BS Uranium Lamp Chopper H PMT Heat Pipe P Chopper Dye Laser L L L Computer Lock-in Amplifier L L Neutral Density Filter P P QW P Laser path Electronics path F Experimental Setup 6

7. Excitation Scheme of the Rb 2 Polarization Experiment Fixed frequency pump laser X 1 Σ g + (0,71) B 1 Π u (2,70) J”=73 69 A/b J’=74 72 70 68 Collisionally populated levels scanning probe laser The angular momentum orientation of the molecules is partially preserved during the collision. The collisionally populated energy levels serve as probe initial levels leading to satellite transitions Previously used in: Kasahara, S. et al, J. Chem. Phys. 111(1999) 7

8. Parent R and P lines to Scale With Collisional Satellite Lines in the Rb 2 Probe Laser Scan In subsequent scans the collisional satellite lines were recorded on a more sensitive scale to enhance the yield beyond the strong R,P lines 8

9. Probe Laser Scan of Rb 2 Collisional Satellite Lines 9

10. Probe Laser Scan of Rb 2 Including P(71) Parent Line 10

11. Probe Laser Scan of Collisional Satellite Lines of Rb 2 Including R(71) Parent Line 11

12. Probe Laser Scan of Satellite Lines of Rb 2 12

13. Rotational Energy Level Data from the Rb 2 Polarization Experiment The DCM dye laser was tuned to 14736.184 cm -1. Two transitions were pumped simultaneously: 13

14. Spectra of the Cs 2 Experiment Pump transitions:and wavenumber (cm -1 ) 14

15. Spectra of the Cs 2 Experiment Pump transitions:and wavenumber (cm -1 ) 15

16. Logarithm of the Franck-Condon Factors Calculated by Prof. T. Bergeman Published in Phys. Rev. A 83, 032514 (2011) Calculated from the potential curves provided by Dr. S. Kotochigova, Temple University 16

17. Cs 2 rotational energy level data for the A~b complex Cs 2 polarization data of A~b states from Temple University. Cs 2 polarization data of A~b states from different sources. 17

18. Theoretical Fit Global deperturbation analysis by Dr. T. Bergeman, SUNY; Dr. S. Kotochigova, Temple University; Dr. A. Drozdova, Dr. E. Pazyuk, Dr. A. V. Stolyarov Moscow State University Analysis published in Phys. Rev. A 83, 032514 (2011 ) Cs 2 A~b potential curves fitted from experimental data Part of our fitted Cs 2 data

19. Conclusion More than 2000 spectral lines for the Rb 2 were observed and 881 of them were assigned. More than 300 spectral lines for the Cs 2 were observed and assigned. Collisional satellite lines with ΔJ up to 58 in Rb 2 and up to 12 in Cs 2 were observed due to collision induced orientation transfer This technique is very useful for enhancing the yield of rotational level data beyond the customary R and P parent lines with ΔJ = ±1 for each pump laser labeled lower level This enhancement of polarization spectroscopy is important in cases where it is difficult to identify spectrally ‘clean’ pump transitions involving only one rovibronic transition. The spectroscopy of the heavier alkali molecules benefits from this approach. 19

20. Funded by NSF PHY 0555608, PHY 0855502, PHY 0652938 and PHY 0968898. Acknowledgements Prof. Tom Bergeman, Stony Brook Dr. H. Salami Dr. Amanda Ross, Lyon and other co-authors who contributed to the subsequent global deperturbation analysis of the A~b complex of Rb 2 : Phys. Rev. A 80, 022515 (2009) and Cs 2 : Phys. Rev. A 83, 032514 (2011 ) 20

21. Funded by NSF PHY 0555608, PHY 0855502, PHY 0652938 and PHY 0968898.

22. Details about the Rb 2 Experiment Pump laser: DCM Dye Laser (30 mW) Probe laser: TiSapphire Laser (4 mW) Temperature: 480K Argon gas pressure: 1 Torr at Room Temperature Calibration: Pump Laser Calibrated by Iodine Lamp; Probe Laser Calibrated by Uranium Lamp

23. Spectral Ranges of Lasers LaserLasing Range TiSapphire(MW)781-943nm KitonRed 620 Dye laser598-645nm Verdi Pump Laser532 nm DCM Dye Laser625-700nm Argon Pump Laser514 nm

24. How to Make Circularly Polarized Light

25. Alkali dimer density DimerT(K)P(Torr)n(cm -3 ) Rb 2 4808.112E-51.62E12 Cs 2 5505.94E-31.03E14