1. HATTIE RING PRESENTATION FOR PHYS 250 4/22/2008 Magnetometry

2. Outline Magnetometers  General Setup  Alkali Cell  Optical Pumping  Optical Probing Methods of Magnetometry  DAVLL  Combined Pumping and Probing  RF vs. DC Magnetometers  SERF regime Magnetometry in MRI  Remote Detection  Future work

3. Magnetometer General Setup Light Source (pump) Light Source (probe)

4. Alkali Cell Alkali Atom Cell

5. Optical Pumping Light Source (pump) Johannes Recht, W. K. (2005). Optical Pumping of Rubidium. Madison

6. Optical Pumping Light Source (pump) Rochester and Budker (2001). Am. J. Phys. 69, 450-4.

7. Optical Pumping Light Source (pump) Johannes Recht, W. K. (2005). Optical Pumping of Rubidium. Madison

8. Optical Pumping Light Source (pump) Magnetic Field Johannes Recht, W. K. (2005). Madison

9. Optical Pumping Causes atomic polarization to precess Rochester and Budker (2001). Am. J. Phys. 69, 450-4. Light Source (pump) Magnetic Field

10. Optical Pumping Light Source (pump) Magnetic Field Black, E. D. (2004). Optical Pumping.

11. Optical Pumping Light Source (pump) Magnetic Field Johannes Recht, W. K. (2005). Madison

12. Probe Light Two different detection modes:  Change in light intensity  Change in polarization Light Source (pump) Light Source (probe)

13. DAVLL Light Source RCLLCL Laser Grating Valeriy V. Yashchuk, D. B., John R. Davis (1999). Review of Scientific Instruments 71(2): 341 - 346.

14. DAVLL Light Source RCLLCL Laser Grating Valeriy V. Yashchuk, D. B., John R. Davis (1999). Review of Scientific Instruments 71(2): 341 - 346.

15. Single Laser Setup Light Source (pump & probe)

16. Rf Magnetometers Light Source (pump) Light Source (probe) Johnson noise can be neglected, allowing for better sensitivity. Rf Coil M. P. Ledbetter, V. M. A., S. M. Rochester, D. Budker, S. Pustelny, V. V. Yashchuk (2008).

17. Spin-Exchange Relaxation Free (SERF) Collision Avoidance:  Buffer gas  Cell coating Two types of collisions in alkali cells:  Spin-exchange collisions  Can be ignored in SERF  Spin-destruction collisions Light Source (pump) Light Source (probe) Oven

18. Nitrogen Magnetometer Pre-polarization Field (~ 3 kG) Encoding Field ( B 0, B x, B y, B z ) Water Out H2OH2O Magnetometer with MRI

19. 2 magnetometer setups DC magnetometers Modulated single laser setup

20. Remote Detection Flow In Flow Out Magnetometer t Detector s(t)

21. Flow In Flow Out Encoding Pulse Magnetometer Remote Detection t Detector s(t)

22. Flow In Flow Out Flow Magnetometer Remote Detection t Detector s(t)

23. Flow In Flow Out Flow Magnetometer Remote Detection t Detector s(t)

24. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

25. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

26. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

27. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

28. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

29. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

30. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

31. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

32. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

33. Flow In Flow Out Flow Magnetometer Remote Detection tt flow Detector s(t)

34. Flow In Flow Out Flow tt flow Signal (nG) Time (s) Detector s(t) Magnetometer Remote Detection

35. 0.5 s0.7 s0.9 s1.1 s1.3 s 1.5 s1.7 s1.9 s2.1 s2.3 s Signal (nG) Time (s) H2OH2O t-sampling Remote Detection Results

36. z y 0.4 s0.6 s0.8 s1.0 s1.2 s 1.4 s1.6 s1.8 s2.0 s2.2 s Resolution: z, 5mm; y, 2.5mm Remote Detection Results

37. z y 0.4 s0.6 s0.8 s1.0 s1.2 s 1.4 s1.6 s1.8 s2.0 s2.2 s Resolution: z, 5mm; y, 2.5mm Remote Detection Results

38. z y 0.4 s0.5 s0.6 s0.7 s0.8 s Flow Mixing Region Remote Detection Results

39. Future Work New System Being Built  Miniaturization  Optimized one-sided geometry  Prepolarization for static imaging  NQR Measurements  Novel prepolarization techniques  Micro-channel flow, Lab- on-a-chip RF Magnetometry  Eliminate point-by-point acquisition  Design of system for direct imaging  The Brain  Hand-held scanners

40. References Black, E. D. (2004). Optical Pumping. http://www.hep.wisc.edu/~prepost/407/opticalpumping/opticalpumping.pdf D. Budker, D. F. K., V. V. Yashchuk, and M. Zolotorev (2002). "Nonlinear magneto- optical rotation with frequency-modulated light." Physical Review A 65(055403): 1 - 4. Dmitry Budker, M. R. (2006). "Optical Magnetometry.“ M. P. Ledbetter, V. M. A., S. M. Rochester, D. Budker, S. Pustelny, V. V. Yashchuk (2008). "Detection of radio frequency magnetic fields using nonlinear magneto- optical rotation.“ I. M Savukov, S. J. S., M. V. Romalis, K. L. Sauer (2005). "Tunable Atomic Magnetometer for Detection of Radio-Frequency Magnetic Fields." Physical Review Letters 95(063004): 1 - 4. Johannes Recht, W. K. (2005). Optical Pumping of Rubidium. Madison Shoujun Xu, S. M. R., Valeriy V. Yashchuk, Marcus. Donaldson, Dmitry Budker (2006). "Construction and applications of an atomic magnetic gradiometer based on nonlinear magneto-optical rotation." Review of Scientific Instruments 77(8) Shoujun Xu, V. V. Y., Marcus H. Donaldson, Simon M. Rochester, Dmitry Budker, and Alex Pines (2006). "Magnetic resonance imaging with an optical atomic magnetometer." PNAS: 1-4. Valeriy V. Yashchuk, D. B., John R. Davis (1999). "Laser frequency stabilization using linear magneto-optics." Review of Scientific Instruments 71(2): 341 - 346.