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Optical frequency metrology

Nature volume 416, pages 233–237 (2002)Cite this article

Abstract

Extremely narrow optical resonances in cold atoms or single trapped ions can be measured with high resolution. A laser locked to such a narrow optical resonance could serve as a highly stable oscillator for an all-optical atomic clock. However, until recently there was no reliable clockwork mechanism that could count optical frequencies of hundreds of terahertz. Techniques using femtosecond-laser frequency combs, developed within the past few years, have solved this problem. The ability to count optical oscillations of more than 1015 cycles per second facilitates high-precision optical spectroscopy, and has led to the construction of an all-optical atomic clock that is expected eventually to outperform today's state-of-the-art caesium clocks.

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Figure 1: Consecutive pulses of the pulse train emitted by a mode-locked laser and the corresponding spectrum.
Figure 2: The first direct radio frequency–optical frequency conversion using a femtosecond laser.
Figure 3: The principle of the single-laser optical synthesizer.
Figure 4: An optical synthesizer in a box.

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References

  1. Bloembergen, N. (ed.) Non-linear Spectroscopy (Proc. Int. School Phys. “Enrico Fermi”) (North Holland, Amsterdam, 1977).

    Google Scholar 

  2. Hänsch, T. W. & Inguscio, M. (eds) Frontiers in Laser Spectroscopy (Proc. Int. School Phys. “Enrico Fermi”) (North Holland, Amsterdam, 1994).

    Google Scholar 

  3. Diddams, S. A. et al. An optical clock based on a single trapped 199Hg ion. Science 293, 825–828 (2001).

    Article  ADS  CAS  Google Scholar 

  4. Evenson, K. M., Wells, J. S., Petersen, F. R., Danielson, B. L. & Day, G. W. Accurate frequencies of molecular transitions used in laser stabilization: the 3.39-μm transition in CH4 and the 9.33- and 10.18-μm transitions in CO2 . Appl. Phys. Lett. 22, 192–195 (1973).

    Article  ADS  CAS  Google Scholar 

  5. Schnatz, H., Lipphardt, B., Helmcke, J., Riehle, F. & Zinner, G. First phase-coherent frequency measurement of visible radiation. Phys. Rev. Lett. 76, 18–21 (1996).

    Article  ADS  CAS  Google Scholar 

  6. Udem, Th. et al. Phase-coherent measurement of the hydrogen 1S-2S transition frequency with an optical frequency interval divider chain. Phys. Rev. Lett. 79, 2646–2649 (1997).

    Article  ADS  CAS  Google Scholar 

  7. Schwob, C. et al. Optical frequency measurement of the 2S-12D transitions in hydrogen and deuterium: Rydberg constant and Lamb shift determinations. Phys. Rev. Lett. 82, 4960–4963 (1999); erratum Phys. Rev. Lett. 86, 4193 (2001).

    Article  ADS  CAS  Google Scholar 

  8. Bernard, J. E. et al. Cs-based frequency measurement of a single trapped ion transition in the visible region of the spectrum. Phys. Rev. Lett. 82, 3228–3231 (1999).

    Article  ADS  CAS  Google Scholar 

  9. Udem, Th. Phasenkohärente optische Frequenzmessungen am Wasserstoffatom. Thesis, Ludwig-Maximilians Univ. (1997).

  10. Reichert, J., Holzwarth, R., Udem, Th. & Hänsch, T. W. Measuring the frequency of light with mode-locked lasers. Opt. Commun. 172, 59–68 (1999).

    Article  ADS  CAS  Google Scholar 

  11. Udem, Th., Reichert, J., Holzwarth, R. & Hänsch, T. W. Accurate measurement of large optical frequency differences with a mode-locked laser. Opt. Lett. 24, 881–883 (1999).

    Article  ADS  CAS  Google Scholar 

  12. Udem, Th., Reichert, J., Holzwarth, R. & Hänsch, T.W. Absolute optical frequency measurement of the cesium D1 line with a mode-locked laser. Phys. Rev. Lett. 82, 3568–3571 (1999).

    Article  ADS  CAS  Google Scholar 

  13. Jones, D. J. et al. Carrier-envelope phase control of femtosecond mode-locked lasers and direct optical frequency synthesis. Science 288, 635–639 (2000).

    Article  ADS  CAS  Google Scholar 

  14. Diddams, S. A. et al. Direct link between microwave and optical frequencies with a 300 THz femtosecond laser comb. Phys. Rev. Lett. 84, 5102–5105 (2000).

    Article  ADS  CAS  Google Scholar 

  15. Reichert, J. et al. Phase coherent vacuum-ultraviolet to radio frequency comparison with a mode-locked laser. Phys. Rev. Lett. 84, 3232–3235 (2000).

    Article  ADS  CAS  Google Scholar 

  16. Niering, M. et al. Measurement of the hydrogen 1S-2S transition frequency by phase coherent comparison with a microwave cesium fountain clock. Phys. Rev. Lett. 84, 5496–5499 (2000).

    Article  ADS  CAS  Google Scholar 

  17. Holzwarth, R. et al. Optical frequency synthesizer for precision spectroscopy. Phys. Rev. Lett. 85, 2264–2267 (2000).

    Article  ADS  CAS  Google Scholar 

  18. Udem, Th. et al. Absolute frequency measurements of the Hg+ and Ca optical clock transitions with a femtosecond laser. Phys. Rev. Lett. 86, 4996–4999 (2001).

    Article  ADS  CAS  Google Scholar 

  19. Stenger, J. et al. Phase-coherent frequency measurement of the Ca intercombination line at 657 nm with a Kerr-lens mode-locked femtosecond laser. Phys Rev. A 63, 021802-1–021802-4 (2001).

    Article  ADS  Google Scholar 

  20. Pokasov, P. V. et al. in Proc. Sixth Symp. Freq. Standards Metrol. (ed. Gill, P.) 510–512 (World Scientific, Singapore, 2002).

    Google Scholar 

  21. Nevsky, A. Yu. et al. Frequency comparison and absolute frequency measurement of I2 stabilized lasers at 532 nm. Opt. Comm. 263, 192–272 (2001).

    Google Scholar 

  22. Holzwarth, R. et al. Absolute frequency measurement of iodine lines with a femtosecond optical synthesizer. Appl. Phys. B 73, 269 (2001).

    Article  ADS  CAS  Google Scholar 

  23. Ye, J. et al. Accuracy comparison of absolute optical frequency measurement between harmonic-generation synthesis and a frequency division femtosecond-comb. Phys. Rev. Lett. 85, 3797–3800 (2000).

    Article  ADS  CAS  Google Scholar 

  24. Lea, S. N. et al. in Proc. Sixth Symp. Freq. Standards Metrol. (ed. Gill, P.) 144–151 (World Scientific, Singapore, 2002).

    Google Scholar 

  25. Dubé, P., Marmet, L., Bernard, J. E., Siemsen, K. J. & Madej, A. A. in Proc. Sixth Symp. Freq. Standards Metrol. (ed. Gill, P.) 489–491 (World Scientific, Singapore, 2002).

    Google Scholar 

  26. Stenger, J., Tamm, Ch., Haverkamp, N., Weyers, S. & Telle, H. R. Absolute frequency measurement of the 435.5 nm 171Yb+-clock transition with a Kerr-lens mode-locked femtosecond laser. Opt. Lett. 26, 1589–1591 (2001).

    Article  ADS  CAS  Google Scholar 

  27. von Zanthier, J. et al. Absolute frequency measurement of the In+ clock transition with a mode-locked laser. Opt. Lett. 25, 1729–1731 (2000).

    Article  ADS  CAS  Google Scholar 

  28. Apolonski, A. et al. Controlling the phase evolution of few-cycle light pulses. Phys. Rev. Lett. 85, 740–743 (2000).

    Article  ADS  CAS  Google Scholar 

  29. Telle, H. R., Steinmeyer, G., Dunlop, A. E., Sutter, D. H. & Keller, U. Carrier-envelope offset phase control: a novel concept for absolute optical frequency measurement and ultrashort pulse generation. Appl. Phys. B 69, 327–332 (1999).

    Article  ADS  CAS  Google Scholar 

  30. Xu, L. et al. Route to phase control of ultrashort light pulses. Opt. Lett. 21, 2008–2010 (1996).

    Article  ADS  CAS  Google Scholar 

  31. Paulus, G. G. et al. Evidence of 'absolute-phase' phenomena in photoionization with few-cycle laser pulses. Nature 414, 182–184 (2001).

    Article  ADS  CAS  Google Scholar 

  32. Drescher M. et al. X-ray pulses approaching the attosecond frontier. Science 291, 1923–1927 (2001).

    Article  ADS  Google Scholar 

  33. Eckstein, J. N., Ferguson, A. I. & Hänsch, T. W. High-resolution two-photon spectroscopy with picosecond light. Phys. Rev. Lett. 40, 847–850 (1978).

    Article  ADS  CAS  Google Scholar 

  34. Chebotayev, V. P. & Ulybin, V. A. Synchronization of atomic quantum transitions by light pulses. Appl. Phys. 50, 1–5 (1990).

    Article  Google Scholar 

  35. Kane, D. M., Bramwell, S. R. & Ferguson, A. I. FM dye lasers. Appl. Phys. B 39, 171–178 (1986).

    Article  ADS  Google Scholar 

  36. Telle, H. R. in Frequency Control of Semiconductor Lasers (ed. Ohtsu, M.) 137–167 (Wiley, New York, 1996).

    Google Scholar 

  37. Hänsch, T.W. in The Hydrogen Atom (eds Bassani, G. F., Inguscio, M. & Hänsch, T. W.) 93–102 (Springer, Berlin, 1989).

    Book  Google Scholar 

  38. Telle, H. R., Meschede, D. & Hänsch, T. W. Realization of a new concept for visible frequency division: phase-locking of harmonic and sum frequencies. Opt. Lett. 15, 532–534 (1990).

    Article  ADS  CAS  Google Scholar 

  39. Wicht, A., Hensley, J. M., Sarajlic, E. & Chu, S. A preliminary measurement of ħ/Mcs with atom interferometry, in Proc. Sixth Symp. Freq. Standards Metrol. (ed. Gill, P.) (World Scientific, Singapore, in the press).

  40. Hensley, J. M. A Precision Measurement of the Fine Strucure Constant. Thesis, Stanford Univ. (2001).

    Google Scholar 

  41. Becker, Th., von Zanthier, J. & Nevsky, A. Yu. High-resolution spectroscopy of a single In+ ion: progress towards an optical frequency standard. Phys. Rev. A 63, 051802-1–051802-4 (2001).

    Article  ADS  Google Scholar 

  42. Udem, Th., Holzwarth, R. & Hänsch, T. W. in Proceeding of Joint Meeting of the 13th European Frequency and Time Forum and 1999 IEEE International Frequency Control Symposium, Besancon, France, 13-16 April 1999 620–625 (IEEE Publications, 1999)

    Google Scholar 

  43. Knight, J. C., Birks, T. A., Russell, P. St. J. & Atkin, D. M. Endlessly single-mode photonic crystal fibre. Opt. Lett. 22, 961–964 (1996).

    Google Scholar 

  44. Wadsworth, W. J. et al. Soliton effects in photonic crystal fibres at 850 nm. Electron. Lett. 36, 53 (2000).

    Article  Google Scholar 

  45. Ranka, J. K., Windeler, R. S. & Stentz, A. J. Visible continuum generation in air-silica microstructure optical fibres with anomalous dispersion at 800 nm. Opt. Lett. 25, 25–28 (2000).

    Article  ADS  CAS  Google Scholar 

  46. Birks, T. A., Wadsworth, W. J. & Russell, P. St. J. Supercontinuum generation in tapered fibres. Opt. Lett. 25, 1415–1417 (2000).

    Article  ADS  CAS  Google Scholar 

  47. Ell, R. et al. Generation of 5-fs pulses and octave-spanning spectra directly from a Tisapphire laser. Opt. Lett. 26, 373–375 (2001).

    Article  ADS  CAS  Google Scholar 

  48. Diddams, S. A., Hollberg, L., Ma, L. S. & Robertson, L. A femtosecond-laser-based optical clockwork with instability 6.3 × 10−16 in 1 s. Opt. Lett. 27, 58 (2002).

    Article  ADS  Google Scholar 

  49. Madej, A. A. & Bernard, J. E. in Frequency Measurement and Control (ed. Luiten, A. N.) 153–194 (Springer, Berlin, 2001).

    Book  Google Scholar 

  50. Riehle, F. & Helmcke, J. in Frequency Measurement and Control (ed. Luiten, A. N.) 95–129 (Springer, Berlin, 2001).

    Book  Google Scholar 

  51. Dirac, P. A. M. The cosmological constants. Nature 139, 323 (1937).

    Article  ADS  Google Scholar 

  52. Karshenboim, S. G. Some possibilities for laboratory searches for variations of fundamental constants. Can. J. Phys. 78, 639–678 (2000).

    Article  ADS  CAS  Google Scholar 

  53. Salomon, Ch. et al. in Atomic Physics 17: XVII Int. Conf. Atom. Phys.; ICAP 2000 (eds Arimondo, E., De Natale, P. & Inguscio, M.) 23–40 (AIP Conf. Proc. Vol. 551) (American Institute of Physics, 2001).

    Google Scholar 

  54. Webb, J. K. et al. Further evidence for cosmological evolution of the fine structure constant. Phys. Rev. Lett. 87, 091301-1–091301-4 (2001).

    Article  ADS  Google Scholar 

  55. Vessot, R. F. C. et al. Test of relativistic gravitation with a space-borne hydrogen maser. Phys. Rev. Lett. 45, 2081–2084 (1980).

    Article  ADS  Google Scholar 

  56. Ferguson, A. I., Eckstein, J. N. & Hänsch, T. W. Polarization spectroscopy with ultrashort light pulses. Appl. Phys. 18, 257 (1979).

    Article  ADS  CAS  Google Scholar 

  57. Wineland, D. J., Bergquist, J. C., Itano, W. M, Diedrich, F. & Weimer, C. S. in The Hydrogen Atom (eds Bassani, G. F., Inguscio, M. & Hänsch, T. W.) 123–133 (Springer, Berlin, 1989.)

    Book  Google Scholar 

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Acknowledgements

We thank our collaborators P. Lemonde, G. Santarelli, M. Abgrall, P. Laurent and A. Clairon (BNM-LPTF, Paris), C. Salomon (ENS, Paris), J. Knight, W. Wadsworth, T. Birks and P. St J. Russell (University of Bath), and J. Hall, S. Diddams, J. Ye and L. Hollberg (NIST, Boulder, Colorado) for the excellent teamwork and stimulating discussions.

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  1. Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, Garching, 85748, Germany

    Th. Udem, R. Holzwarth & T. W. Hänsch

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  1. Th. Udem
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Correspondence to Th. Udem.

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Udem, T., Holzwarth, R. & Hänsch, T. Optical frequency metrology. Nature 416, 233–237 (2002). https://doi.org/10.1038/416233a

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