Precision Spectroscopy of the 9s and 8p levels of Francium. by Seth Aubin Graduate Students: Eduardo Gomez Kerim Gulyuz Jerry Sell Professors: Luis A. Orozco Gene D. Sprouse Work supported by NSF University of Toronto

Precision Spectroscopy in Francium Objective: Spectroscopy probes electronic wavefunctions Lifetime  wavefunctions far from nucleus Hyperfine splitting  wavefunction near nucleus Importance:  Francium is the heaviest alkali (Z=87).  Test of wavefunctions in relativistic regime.  Parity non-conservation experiments.

: Construction of 1 st production and trapping apparatus. 1995: Produced and Trapped Francium in a MOT : Laser spectroscopy of Francium (8S 1/2, 7P 1/2,7D 5/2,7D 3/2, hyperfine anomaly) : high efficiency trap. 2003: Spectroscopy of the 9S 1/2, 8P 1/2, and 8P 3/2 levels. 3,000 atom Fr MOT A Brief History of Francium at Stony Brook 140,000 atom Fr MOT

Excitation of the 9s level of 210 Fr

E1 decay channels of the 9s and 8p levels

Lifetime Measurement Method: Time-Correlated Single Photon Counting 1.Excite atom. 2.Fast turn off of excitation. 3.Detect photon from spontaneous emission and measure its arrival time. 4.The histogram of arrival times follows the exponential decay of the excited state.

Optical Excitation Setup ~10, Fr atoms

Timing

Lifetime Measurements: Time-correlated Single-photon Counting ~10, Fr atoms

9s lifetime data and fit

Results for 9S 1/2 Lifetime Error % Statistical± 0.72 TAC/MCA performance < ± 0.04 Displacement error from Rb < ± 0.38 Quantum beats < ± 0.20 Total± 0.84 % Opt. Lett. 28, 2055 (2003)

Comparison with Theory a = M. S. Safronova et al. b = V. A. Dzuba et al. c = M. Marinescu et al. d = W. A. van Wijngaarden et al. e = E. Biémont et al. f = C. E. Theodosiou et al.

8p lifetimes

8P 3/2 lifetime data

Results for 8P 3/2 Lifetime Error % Statistical± 1.05 Bayesian (9S 1/2 )± 1.44 TAC/MCA performance < ± 0.30 Contamination shift error ± 0.03 Total± 1.8 %

Bayesian Error: error on  2 due to error on  1

Comparison with Theory a = M. S. Safronova et al. b = V. A. Dzuba et al. c = W. A. van Wijngaarden et al. d = E. Biémont et al. e = C. E. Theodosiou et al.

8P 1/2 lifetime data untilted 436 nm filtertilted 436 nm filter

Results for 8P 1/2 Lifetime Error % Statistical± 2.3 Bayesian± 0.4 TAC/MCA performance < ± 0.2 Total± 2.3 %

Comparison with Theory a = M. S. Safronova et al. b = V. A. Dzuba et al. c = W. A. van Wijngaarden et al. d = E. Biémont et al. e = C. E. Theodosiou et al.

Hyperfine Splitting (HFS)  Scan probe laser across F=11/2 and F=13/2 hyperfine levels of the 9S 1/2 level.  Record fluorescence vs. frequency Method: With wavemeter: HFS =  1.5 MHz (statistical)

Cavity as frequency ruler With wavemeter: HFS =  3.2 MHz (statistical)

Confirmation of Quantum Defect Theory

SUMMARY  Measurements of the 9S 1/2 lifetime and HFS.  Measurements of the 8P 3/2 and 8P 1/2 lifetimes.  Theoretical predictions agree with lifetime measurements.  Future: use HFS to extract nuclear g-factor for 210 Fr.