Optical frequency metrology

Strontium optical clock

Atomic fountains using cold cesium atoms, currently defining the second from a microwave atomic transition, will soon reach their ultimate accuracy. In the near future, optical clocks based on narrow atomic transitions in the visible spectrum will certainly prove to be better frequency standards than fountains.

An optical atomic clock using strontium atoms is being developed at SYRTE. To reach high accuracy, strontium atoms are slowed down — or cooled — and trapped in a lattice of optical dipole traps. The frequency of the clock transition of strontium has been measured by probing with an ultra-stable laser and by comparison with a cesium fountain. An accuracy of 10-14 has been achieved by measuring and canceling perturbations due to the trapping potential. Strontium optical clock are expected to soon provide a better accuracy than in the best atomic fountains. Further characterization will therefore be achieved by comparison with a second strontium clock, currently under construction.

High vacuum enclosure Clock in operation
Left: High vacuum enclosure where strontium atoms are trapped in an optical lattice.
Right: Clock in operation: the blue lasers slow down the strontium atoms.

Publications

Experimental realization of an optical second with strontium lattice clocks
R. Le Targat et al.
Nature Communications 4, 2109 (2013)

Optical Lattice Clocks as Candidates for a Possible Redefinition of the SI Second
Gurov, M. and McFerran, J.J. and Nagorny, B. and Tyumenev, R. and Xu, Z. and Le Coq, Y. and Le Targat, R. and Lemonde, P. and Lodewyck, J. and Bize, S.
IEEE Transactions on Instrumentation and Measurement 62, 1568-1573 (2013)

Observation and cancellation of the dc Stark shift in strontium optical lattice clocks
Lodewyck, J., Zawada, M., Lorini, L., et al.
IEEE Transactions on UFFC 59, 411 (2012)

Lattice-Induced Frequency Shifts in Sr Optical Lattice Clocks at the 10-17 Level
Westergaard, P. G., Lodewyck, J., Lorini, L., et al.
Physical Review Letters 106 210801 (2011)

Frequency stability of optical lattice clocks
Lodewyck, J., Westergaard, P. G., Lecallier, A., et al.
New Journal of Physics 12 065026 (2010)

Minimizing the dick effect in an optical lattice clock
Westergaard, P., Lodewyck, J., Lemonde, P.
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 57 623-628 (2010)

Ultrastable lasers based on vibration insensitive cavities
J. Millo et al.
Phys. Rev. A 79, 053829 (2009)

Nondestructive measurement of the transition probability in a Sr optical lattice clock
Lodewyck, J., Westergaard, P. G., Lemonde, P.
Physical Review A 79 061401 (2009)

New Limits on Coupling of Fundamental Constants to Gravity Using 87Sr Optical Lattice Clocks
Blatt, S., Ludlow, A. D., Campbell, G. K., et al.
Physical Review Letters 100 140801 (2008)

An optical lattice clock with spin-polarized 87Sr atoms
Baillard, X., Fouché, M., Targat, R. Le, et al.
The European Physical Journal D 48 11-17 (2008)

Accuracy evaluation of an optical lattice clock with bosonic atoms
Baillard, X., Fouché, M., Le Targat, R., et al.
Optics Letters 32 1812-1814 (2007)

Accuracy Evaluation of a 87Sr Optical Lattice Clock
Fouche, M., Targat, R. Le, Baillard, X., et al.
IEEE Transactions on Instrumentation and Measurement 56 336-340 (2007)

Interference-filter-stabilized external-cavity diode lasers
Baillard, X., Gauguet, A., Bize, S., et al.
Optics Communications 266 609-613 (2006)

Hyperpolarizability Effects in a Sr Optical Lattice Clock
Brusch, A., Le Targat, R., Baillard, X., et al.
Physical Review Letters 96 103003 (2006)

Accurate Optical Lattice Clock with 87Sr Atoms
Targat, R. Le, Baillard, X., Fouché, M., et al.
Physical Review Letters 97 130801 (2006)

Optical lattice clock with atoms confined in a shallow trap
Lemonde, P., Wolf, P.
Physical Review A 72 033409 (2005)

The Dick effect for an optical frequency standard
Quessada, A., Kovacich, R. P., Courtillot, I. ne, et al.
Journal of Optics B: Quantum and Semiclassical Optics 5 S150-S154 (2003)

Cold strontium atoms for an optical frequency standard
Courtillot, I., Quessada, A., Kovacich, R. P., et al.
IEEE Transactions on Instrumentation and Measurement 52 255-257 (2003)

Efficient cooling and trapping of strontium atoms
Courtillot, I., Quessada, A., Kovacich, R. P., et al.
Optics Letters 28 468-470 (2003)

Clock transition for a future optical frequency standard with trapped atoms
Courtillot, I., Quessada, A., Kovacich, R. P., et al.
Physical Review A 68 030501 (2003)

Contact

Jérôme Lodewyck
  • Email: jerome.lodewyck (at) obspm.fr
  • Tel.: +33 (0) 1 40 51 22 24