High-resolution spectroscopy with a femtosecond laser

frequency comb

Vladislav Gerginov1, Scott Diddams2, Albrecht Bartels2, Carol E. Tanner1 and Leo Hollberg2

1Department of physics, University of Notre Dame, Notre Dame, IN 465562National Institute of Standards and Technology, 325 Broadway M.S. 847, Boulder, CO 80305

Atomic number: 55Atomic weight: 132.9 a.u.El. Configuration: [Xe] 6s1

Nuclear angular momentum 7/2Tmelt. = 28.4oCTevap. = 669oCLifetime 6P3/2 = 30.462(3) ns (1)

Lifetime 6P1/2 = 34.88(2) ns (1)

Nucl. dipole moment:I = 2.5827681(14) N

(2)

Nucl. quadrupole moment:Q = - 3.431(1) mbarn (3)

HFS 6S1/2 (4)

HFS 6P1/2 (preliminary)HFS 6P3/2 (5)

1 C.Amiot et al., Phys. Rev. A66, 052506 (2002)2 P. Raghavan, At. Data Nucl. Data Tables, 42, 189 (1989)3 J. Cederberg et al., J.Chem. Phys. 111 (18), 8396 (1999)4 International Agreement5 V. Gerginov et al., Phys. Rev. Lett. 91,072501 (2003)

Pulsed laser spectroscopy1970s: Ideas of 2-photon spectroscopy with pulsed sources from T. W. Hänsch and V. P. Chebotaev;

“Narrow resonances of two-photon absorption of super-narrow pulses in a gas” Y. V. Baklanov and V. P. Chebotaev, Appl. Phys. 12, 97 (1977).

“Coherent Two-Photon Excitation by Multiple Light Pulses”R. Teets, J. Eckstein, and T. W. HänschPhys. Rev. Lett. 38, 760-764 (1977).

“Two-photon spectroscopy of laser-cooled Rb using a mode-locked laser”, M. J. Snadden, A. S. Bell, E. Riis, A. I. Ferguson, Opt. Commun, 125, 70-76, (1996).

“High sensitivity phase spectroscopy with picosecond resolution”J. –C. Diels, B. Atherton, S. Diddams;Proceedings of 5th European Quantum Electronics Conference, 29 195–195, (1994).

“United Time-Frequency Spectroscopy for Dynamics and Global Structure”, A. Marian, M. C. Stowe, J. R. Lawall, D. Felinto, J. Ye, Science Express, 1105660, 2004.

Experimental setup

Femtosecond Laser Spectral Output

D1 line spectrum @ 14nW CW power

D2 line spectrum –CW excitation

D2 line spectrum @ 1.5nW CW power

Overlapped spectral components

D1 Line Measurements

F-F’ Previous1 (kHz) This work (kHz) Difference (kHz) AC Stark shift (kHz)

F3-F3 335120562759.7(4.9) 335120562753.7(85.0) -6.0 ( 0.1 sigma) Not meas.

F3-F4 335121730483.2(5.3) 335121730500.8(16.4) 17.6 (1 sigma) -36.0(31.4)

F4-F3 335111370130.2(4.6) 335111370146.3(10.5) 16.1 (1.4 sigma) -20.7(9.5)

F4-F4 335112537853.9(4.0) 335112537861.7(28.0) 7.8 ( 0.3 sigma) Not meas.

1V. Gerginov, K. Calkins, C. E. Tanner, A. Bartels, J. McFerran, S. Diddams, L. Hollberg, to be submitted.

F-F’ Previous1 (kHz) This work (kHz) Difference (kHz)

F3-F2 351730549621.5)5.5( 351730549616.3)9.7( -5.2) 0.5 sigma(

F3-F3 351730700845.9)5.5( 351730700766.1)98.5( -79.8)0.8 sigma(

F3-F4 351730902133.2)5.6( 351730902116.9)34.2( -16.3) 0.5 sigma(

F4-F3 351721508210.5)5.5( 351721508195.1)21.7( -15.4) 0.7 sigma(

F4-F4 351721709496.9)5.5( 351721709471.6)167.8( -25.3 )0.2 sigma(

F4-F5 351721960585.7)5.5( 351721960563.5)4.5( -22.2 )3 sigma(

D2 Line Measurements

1V. Gerginov, C. E. Tanner, S. Diddams, A. Bartels, L. Hollberg, PRA 70, 042505, 2004

Cs D2 Line Optical Clock

Frequency reference Combining the optical frequencies of the D lines, the repetition rate

and the offset frequency of the femtosecond laser can be referenced to an atomic transition.

Optical frequency 351730549621500HzRepetition rate 998.6390777MHzComponent number N=352210Accuracy 60kHz (1.7x10-10)Instability 3.5kHz (10-11) @ 100s

Conclusions

1. One-photon spectroscopy using the output of a femtosecond laser;

2. Optical frequency measurements with accuracy better than 100kHz;

3. SubDoppler spectroscopy with 1nW laser power;4. Potential femtosecond-laser based optical clocks.