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Time Evolution of Coherent Excitation (STIRAP)

Time Evolution of Coherent Excitation (STIRAP). Time Evolution of Coherent Excitation (STIRAP). How Camp 7 April, 2004. How Camp 7 April, 2004. Rabi Period. 1.0. 0.5. 0.0. What is Coherent Excitation?. What is Coherent Excitation?. 2-Level. 1.0. |2>. ARP. Coherent.

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Time Evolution of Coherent Excitation (STIRAP)

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  1. Time Evolution of Coherent Excitation (STIRAP) Time Evolution of Coherent Excitation (STIRAP) How Camp 7 April, 2004 How Camp 7 April, 2004

  2. Rabi Period 1.0 0.5 0.0 What is Coherent Excitation? What is Coherent Excitation? 2-Level 1.0 |2> ARP Coherent Excited population 0.5 Incoherent 0.0 |1> Time

  3. Stokes Pump 3-Level Rabi Frequency |3> Stokes Time |2> 1 |1> Pump Excited Fraction |2> |1> |3> 0 Time What is STIRAP? What is STIRAP?

  4. Applications Applications • Control of Chemical Reactions • Atom Optics • Laser Cooling • Measurement of Weak B-Fields • Cavity QED • BEC From Bergmann, et al. Annu. Rev. Phys. Chem. (2001)

  5. Technique: What Others Do Technique: What Others Do 85Rb 5D5/2 F’’=5 Stokes 6P3/2 776 nm 5P3/2 F’=4 Monitor 420 nm fluorescence from 6P-5S transition Pump 780 nm Monitor 780 nm fluorescence from MOT 5S1/2 F=3

  6. Problems: • Inability to see all transitions • Time resolution limited by lifetimes Problems: 85Rb • Inaccurate measure of 5S atoms 5D5/2 F’’=5 Stokes 6P3/2 776 nm 5P3/2 F’=4 Monitor 420 nm fluorescence from 6P-5S transition Pump 780 nm Monitor 780 nm fluorescence from MOT 5S1/2 F=3

  7. Technique: What We Can Do Technique: What We Can Do 87Rb 4D5/2 F’’=4 Stokes • Accurate excited-state fractions 1529 nm 5P3/2 F’=3 • Measure all 3 populations Pump 780 nm • Monitor time-evolution of process (~2 ns resolution) 5S1/2 F=2

  8. What Theory Predicts What Theory Predicts Stokes (L2) Pump (L1) Delay = -30 ns 4D 5P 5S

  9. What Theory Predicts Stokes (L2) Pump (L1) 4D 5P 5S What Theory Predicts

  10. MOTRIMS MOTRIMS Technique: How We Do It Technique: How We Do It

  11. Q-Value Spectra Q-Value Spectra 5s-3p 4d-3d 5s-3s

  12. Hold That Thought! Hold That Thought!

  13. Simplified Experimental Setup Simplified Experimental Setup 7 KeV Na+ Rb Pump Laser (L1) Diameter: ~ 200 mm MOT Diameter: ~ 600 - 800 mm Ion Beam Diameter: ~ 500 mm Stokes Laser (L2) Diameter: ~ 350 mm

  14. STIRAP Laser Timing STIRAP Laser Timing Trap Off Time: ~ 0.5 ms Stokes (L2) ON ~50 ns Trapping Lasers ON Trapping Lasers ON Pump (L1) ON ~50 ns Total Period: 5 ms

  15. Correlating Q-Value & Laser Timing Correlating Q-Value & Laser Timing 2D TAC Spectra + =

  16. 5p-3p 4d-3s 4d-3d TAC Spectra 2.5 TAC Spectra 5s-3p 5p-3p 5s-3s 2.0 1.5 Time (ms) 1.0 0.5 0.0 50 100 150 Q-Value (Channel)

  17. Time Evolution of STIRAP Time Evolution of STIRAP

  18. Future Work Future Work • Explore Temporal Evolution of STIRAP: • Pulse Delay • Pulse Width • Laser Intensity • Laser Detuning • See Rabi Flops ?!

  19. New MOTRIMS! New MOTRIMS!

  20. New MOTRIMS! New MOTRIMS!

  21. New MOTRIMS! New MOTRIMS!

  22. New MOTRIMS! New MOTRIMS!

  23. New MOTRIMS! New MOTRIMS!

  24. New MOTRIMS! New MOTRIMS!

  25. New MOTRIMS! New MOTRIMS!

  26. New MOTRIMS! New MOTRIMS!

  27. New MOTRIMS! New MOTRIMS!

  28. New MOTRIMS! New MOTRIMS!

  29. New MOTRIMS! New MOTRIMS!

  30. New MOTRIMS! New MOTRIMS!

  31. p P’ p p p r || p ^ r p r How Do We Measure Q Value? How Do We Measure Q Value? q Q: energy defect : Scattering angle (Lab frame) Pr|| , Pr: parallel and perpendicular recoil momentum components PP , PP’ : projectile momentum before and after the collision Vp: projectile velocity nc: number of transferred electrons

  32. Chopping Our Lasers Chopping Our Lasers

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