Abstract

Sub-Doppler broadband multi-heterodyne spectroscopy is proposed and experimentally demonstrated. Using two laser frequency combs of slightly different repetition frequencies, we have recorded Doppler-free two-photon dual-comb spectra of atomic rubidium resonances of a width of 6 MHz, while simultaneously interrogating a spectral span of 10 THz. The atomic transitions are uniquely identified via the intensity modulation of the observed fluorescence radiation. To the best of our knowledge, these results represent the first demonstration of Doppler-free Fourier transform spectroscopy and extend the range of applications of broadband spectroscopy towards precision nonlinear spectroscopy.

© 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Full Article  |  PDF Article
OSA Recommended Articles
Precise and highly-sensitive Doppler-free two-photon absorption dual-comb spectroscopy using pulse shaping and coherent averaging for fluorescence signal detection

Akiko Nishiyama, Yoshiaki Nakajima, Ken’ichi Nakagawa, and Kaoru Minoshima
Opt. Express 26(7) 8957-8967 (2018)

Doppler-free dual-comb spectroscopy of Rb using optical-optical double resonance technique

Akiko Nishiyama, Satoru Yoshida, Yoshiaki Nakajima, Hiroyuki Sasada, Ken’ichi Nakagawa, Atsushi Onae, and Kaoru Minoshima
Opt. Express 24(22) 25894-25904 (2016)

Doppler-free spectroscopy using a continuous-wave optical frequency synthesizer

Hajime Inaba, Takeshi Ikegami, Feng-Lei Hong, Youichi Bitou, Atsushi Onae, Thomas R. Schibli, Kaoru Minoshima, and Hirokazu Matsumoto
Appl. Opt. 45(20) 4910-4915 (2006)

References

  • View by:
  • |
  • |
  • |

  1. G. Guelachvili, Appl. Opt. 16, 2097 (1977).
    [Crossref]
  2. S. Albert, K. Keppler Albert, P. Lerch, and M. Quack, Faraday Discuss. 150, 71 (2011).
    [Crossref]
  3. B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
    [Crossref]
  4. R. Teets, J. Eckstein, and T. W. Hänsch, Phys. Rev. Lett. 38, 760 (1977).
    [Crossref]
  5. Y. V. Baklanov and V. P. Chebotayev, Appl. Phys. 12, 97 (1977).
    [Crossref]
  6. J. N. Eckstein, A. I. Ferguson, and T. W. Hänsch, Phys. Rev. Lett. 40, 847 (1978).
    [Crossref]
  7. E. Peters, D. C. Yost, A. Matveev, T. W. Hänsch, and T. Udem, Annalen der Physik 525, L29 (2013).
    [Crossref]
  8. A. Ozawa and Y. Kobayashi, Phys. Rev. A 86, 022514 (2012).
    [Crossref]
  9. I. Barmes, S. Witte, and K. S. E. Eikema, Nat. Photonics 7, 38 (2013).
    [Crossref]
  10. T. Ideguchi, B. Bernhardt, G. Guelachvili, T. W. Hänsch, and N. Picqué, Opt. Lett. 37, 4498 (2012).
    [Crossref]
  11. T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, Nature 502, 355 (2013).
    [Crossref]
  12. A. Hipke, S. A. Meek, T. Ideguchi, T. W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).
    [Crossref]
  13. K. J. Mohler, B. J. Bohn, M. Yan, G. Mélen, T. W. Hänsch, and N. Picqué, Opt. Lett. 42, 318 (2017).
    [Crossref]
  14. A. Asahara and K. Minoshima, APL Photon. 2, 041301 (2017).
    [Crossref]
  15. B. Lomsadze and S. T. Cundiff, Opt. Lett. 42, 2346 (2017).
    [Crossref]
  16. N. F. Ramsey, Phys. Rev. 78, 695 (1950).
    [Crossref]
  17. M. M. Salour and C. Cohen-Tannoudji, Phys. Rev. Lett. 38, 757 (1977).
    [Crossref]
  18. A. Hipke, S. A. Meek, G. Guelachvili, T. W. Hänsch, and N. Picqué, Conference on Lasers and Electro Optics (CLEO), OSA Postdeadline Paper Digest (online) (Optical Society of America, 2013), paper CTh5C.8.
  19. Z. Chen, M. Yan, T. W. Hänsch, and N. Picqué, “A phase-stable dual-comb interferometer,” arXiv:1705.04214 (2017).
  20. R. K. Altmann, S. Galtier, L. S. Dreissen, and K. S. E. Eikema, Phys. Rev. Lett. 117, 173201 (2016).
    [Crossref]
  21. A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
    [Crossref]

2017 (3)

2016 (2)

B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
[Crossref]

R. K. Altmann, S. Galtier, L. S. Dreissen, and K. S. E. Eikema, Phys. Rev. Lett. 117, 173201 (2016).
[Crossref]

2014 (1)

A. Hipke, S. A. Meek, T. Ideguchi, T. W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).
[Crossref]

2013 (3)

T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, Nature 502, 355 (2013).
[Crossref]

E. Peters, D. C. Yost, A. Matveev, T. W. Hänsch, and T. Udem, Annalen der Physik 525, L29 (2013).
[Crossref]

I. Barmes, S. Witte, and K. S. E. Eikema, Nat. Photonics 7, 38 (2013).
[Crossref]

2012 (3)

T. Ideguchi, B. Bernhardt, G. Guelachvili, T. W. Hänsch, and N. Picqué, Opt. Lett. 37, 4498 (2012).
[Crossref]

A. Ozawa and Y. Kobayashi, Phys. Rev. A 86, 022514 (2012).
[Crossref]

A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
[Crossref]

2011 (1)

S. Albert, K. Keppler Albert, P. Lerch, and M. Quack, Faraday Discuss. 150, 71 (2011).
[Crossref]

1978 (1)

J. N. Eckstein, A. I. Ferguson, and T. W. Hänsch, Phys. Rev. Lett. 40, 847 (1978).
[Crossref]

1977 (4)

M. M. Salour and C. Cohen-Tannoudji, Phys. Rev. Lett. 38, 757 (1977).
[Crossref]

G. Guelachvili, Appl. Opt. 16, 2097 (1977).
[Crossref]

R. Teets, J. Eckstein, and T. W. Hänsch, Phys. Rev. Lett. 38, 760 (1977).
[Crossref]

Y. V. Baklanov and V. P. Chebotayev, Appl. Phys. 12, 97 (1977).
[Crossref]

1950 (1)

N. F. Ramsey, Phys. Rev. 78, 695 (1950).
[Crossref]

Albert, S.

S. Albert, K. Keppler Albert, P. Lerch, and M. Quack, Faraday Discuss. 150, 71 (2011).
[Crossref]

Allison, T. K.

A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
[Crossref]

Altmann, R. K.

R. K. Altmann, S. Galtier, L. S. Dreissen, and K. S. E. Eikema, Phys. Rev. Lett. 117, 173201 (2016).
[Crossref]

Asahara, A.

A. Asahara and K. Minoshima, APL Photon. 2, 041301 (2017).
[Crossref]

Baklanov, Y. V.

Y. V. Baklanov and V. P. Chebotayev, Appl. Phys. 12, 97 (1977).
[Crossref]

Barmes, I.

I. Barmes, S. Witte, and K. S. E. Eikema, Nat. Photonics 7, 38 (2013).
[Crossref]

Bernhardt, B.

T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, Nature 502, 355 (2013).
[Crossref]

T. Ideguchi, B. Bernhardt, G. Guelachvili, T. W. Hänsch, and N. Picqué, Opt. Lett. 37, 4498 (2012).
[Crossref]

Bjork, B. J.

B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
[Crossref]

Bohn, B. J.

Changala, P. B.

B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
[Crossref]

Chebotayev, V. P.

Y. V. Baklanov and V. P. Chebotayev, Appl. Phys. 12, 97 (1977).
[Crossref]

Chen, Z.

Z. Chen, M. Yan, T. W. Hänsch, and N. Picqué, “A phase-stable dual-comb interferometer,” arXiv:1705.04214 (2017).

Cingöz, A.

A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
[Crossref]

Cohen-Tannoudji, C.

M. M. Salour and C. Cohen-Tannoudji, Phys. Rev. Lett. 38, 757 (1977).
[Crossref]

Cundiff, S. T.

Doyle, J. M.

B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
[Crossref]

Dreissen, L. S.

R. K. Altmann, S. Galtier, L. S. Dreissen, and K. S. E. Eikema, Phys. Rev. Lett. 117, 173201 (2016).
[Crossref]

Eckstein, J.

R. Teets, J. Eckstein, and T. W. Hänsch, Phys. Rev. Lett. 38, 760 (1977).
[Crossref]

Eckstein, J. N.

J. N. Eckstein, A. I. Ferguson, and T. W. Hänsch, Phys. Rev. Lett. 40, 847 (1978).
[Crossref]

Eikema, K. S. E.

R. K. Altmann, S. Galtier, L. S. Dreissen, and K. S. E. Eikema, Phys. Rev. Lett. 117, 173201 (2016).
[Crossref]

I. Barmes, S. Witte, and K. S. E. Eikema, Nat. Photonics 7, 38 (2013).
[Crossref]

Ferguson, A. I.

J. N. Eckstein, A. I. Ferguson, and T. W. Hänsch, Phys. Rev. Lett. 40, 847 (1978).
[Crossref]

Fermann, M. E.

A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
[Crossref]

Galtier, S.

R. K. Altmann, S. Galtier, L. S. Dreissen, and K. S. E. Eikema, Phys. Rev. Lett. 117, 173201 (2016).
[Crossref]

Guelachvili, G.

T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, Nature 502, 355 (2013).
[Crossref]

T. Ideguchi, B. Bernhardt, G. Guelachvili, T. W. Hänsch, and N. Picqué, Opt. Lett. 37, 4498 (2012).
[Crossref]

G. Guelachvili, Appl. Opt. 16, 2097 (1977).
[Crossref]

A. Hipke, S. A. Meek, G. Guelachvili, T. W. Hänsch, and N. Picqué, Conference on Lasers and Electro Optics (CLEO), OSA Postdeadline Paper Digest (online) (Optical Society of America, 2013), paper CTh5C.8.

Hänsch, T. W.

K. J. Mohler, B. J. Bohn, M. Yan, G. Mélen, T. W. Hänsch, and N. Picqué, Opt. Lett. 42, 318 (2017).
[Crossref]

A. Hipke, S. A. Meek, T. Ideguchi, T. W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).
[Crossref]

T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, Nature 502, 355 (2013).
[Crossref]

E. Peters, D. C. Yost, A. Matveev, T. W. Hänsch, and T. Udem, Annalen der Physik 525, L29 (2013).
[Crossref]

T. Ideguchi, B. Bernhardt, G. Guelachvili, T. W. Hänsch, and N. Picqué, Opt. Lett. 37, 4498 (2012).
[Crossref]

J. N. Eckstein, A. I. Ferguson, and T. W. Hänsch, Phys. Rev. Lett. 40, 847 (1978).
[Crossref]

R. Teets, J. Eckstein, and T. W. Hänsch, Phys. Rev. Lett. 38, 760 (1977).
[Crossref]

A. Hipke, S. A. Meek, G. Guelachvili, T. W. Hänsch, and N. Picqué, Conference on Lasers and Electro Optics (CLEO), OSA Postdeadline Paper Digest (online) (Optical Society of America, 2013), paper CTh5C.8.

Z. Chen, M. Yan, T. W. Hänsch, and N. Picqué, “A phase-stable dual-comb interferometer,” arXiv:1705.04214 (2017).

Hartl, I.

A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
[Crossref]

Heckl, O. H.

B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
[Crossref]

Hipke, A.

A. Hipke, S. A. Meek, T. Ideguchi, T. W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).
[Crossref]

A. Hipke, S. A. Meek, G. Guelachvili, T. W. Hänsch, and N. Picqué, Conference on Lasers and Electro Optics (CLEO), OSA Postdeadline Paper Digest (online) (Optical Society of America, 2013), paper CTh5C.8.

Holzner, S.

T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, Nature 502, 355 (2013).
[Crossref]

Ideguchi, T.

A. Hipke, S. A. Meek, T. Ideguchi, T. W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).
[Crossref]

T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, Nature 502, 355 (2013).
[Crossref]

T. Ideguchi, B. Bernhardt, G. Guelachvili, T. W. Hänsch, and N. Picqué, Opt. Lett. 37, 4498 (2012).
[Crossref]

Keppler Albert, K.

S. Albert, K. Keppler Albert, P. Lerch, and M. Quack, Faraday Discuss. 150, 71 (2011).
[Crossref]

Kobayashi, Y.

A. Ozawa and Y. Kobayashi, Phys. Rev. A 86, 022514 (2012).
[Crossref]

Lerch, P.

S. Albert, K. Keppler Albert, P. Lerch, and M. Quack, Faraday Discuss. 150, 71 (2011).
[Crossref]

Lomsadze, B.

Matveev, A.

E. Peters, D. C. Yost, A. Matveev, T. W. Hänsch, and T. Udem, Annalen der Physik 525, L29 (2013).
[Crossref]

Meek, S. A.

A. Hipke, S. A. Meek, T. Ideguchi, T. W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).
[Crossref]

A. Hipke, S. A. Meek, G. Guelachvili, T. W. Hänsch, and N. Picqué, Conference on Lasers and Electro Optics (CLEO), OSA Postdeadline Paper Digest (online) (Optical Society of America, 2013), paper CTh5C.8.

Mélen, G.

Minoshima, K.

A. Asahara and K. Minoshima, APL Photon. 2, 041301 (2017).
[Crossref]

Mohler, K. J.

Ozawa, A.

A. Ozawa and Y. Kobayashi, Phys. Rev. A 86, 022514 (2012).
[Crossref]

Patterson, D.

B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
[Crossref]

Peters, E.

E. Peters, D. C. Yost, A. Matveev, T. W. Hänsch, and T. Udem, Annalen der Physik 525, L29 (2013).
[Crossref]

Picqué, N.

K. J. Mohler, B. J. Bohn, M. Yan, G. Mélen, T. W. Hänsch, and N. Picqué, Opt. Lett. 42, 318 (2017).
[Crossref]

A. Hipke, S. A. Meek, T. Ideguchi, T. W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).
[Crossref]

T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, Nature 502, 355 (2013).
[Crossref]

T. Ideguchi, B. Bernhardt, G. Guelachvili, T. W. Hänsch, and N. Picqué, Opt. Lett. 37, 4498 (2012).
[Crossref]

A. Hipke, S. A. Meek, G. Guelachvili, T. W. Hänsch, and N. Picqué, Conference on Lasers and Electro Optics (CLEO), OSA Postdeadline Paper Digest (online) (Optical Society of America, 2013), paper CTh5C.8.

Z. Chen, M. Yan, T. W. Hänsch, and N. Picqué, “A phase-stable dual-comb interferometer,” arXiv:1705.04214 (2017).

Quack, M.

S. Albert, K. Keppler Albert, P. Lerch, and M. Quack, Faraday Discuss. 150, 71 (2011).
[Crossref]

Ramsey, N. F.

N. F. Ramsey, Phys. Rev. 78, 695 (1950).
[Crossref]

Ruehl, A.

A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
[Crossref]

Salour, M. M.

M. M. Salour and C. Cohen-Tannoudji, Phys. Rev. Lett. 38, 757 (1977).
[Crossref]

Spaun, B.

B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
[Crossref]

Teets, R.

R. Teets, J. Eckstein, and T. W. Hänsch, Phys. Rev. Lett. 38, 760 (1977).
[Crossref]

Udem, T.

E. Peters, D. C. Yost, A. Matveev, T. W. Hänsch, and T. Udem, Annalen der Physik 525, L29 (2013).
[Crossref]

Witte, S.

I. Barmes, S. Witte, and K. S. E. Eikema, Nat. Photonics 7, 38 (2013).
[Crossref]

Yan, M.

K. J. Mohler, B. J. Bohn, M. Yan, G. Mélen, T. W. Hänsch, and N. Picqué, Opt. Lett. 42, 318 (2017).
[Crossref]

Z. Chen, M. Yan, T. W. Hänsch, and N. Picqué, “A phase-stable dual-comb interferometer,” arXiv:1705.04214 (2017).

Ye, J.

B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
[Crossref]

A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
[Crossref]

Yost, D. C.

E. Peters, D. C. Yost, A. Matveev, T. W. Hänsch, and T. Udem, Annalen der Physik 525, L29 (2013).
[Crossref]

A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
[Crossref]

Annalen der Physik (1)

E. Peters, D. C. Yost, A. Matveev, T. W. Hänsch, and T. Udem, Annalen der Physik 525, L29 (2013).
[Crossref]

APL Photon. (1)

A. Asahara and K. Minoshima, APL Photon. 2, 041301 (2017).
[Crossref]

Appl. Opt. (1)

Appl. Phys. (1)

Y. V. Baklanov and V. P. Chebotayev, Appl. Phys. 12, 97 (1977).
[Crossref]

Faraday Discuss. (1)

S. Albert, K. Keppler Albert, P. Lerch, and M. Quack, Faraday Discuss. 150, 71 (2011).
[Crossref]

Nat. Photonics (1)

I. Barmes, S. Witte, and K. S. E. Eikema, Nat. Photonics 7, 38 (2013).
[Crossref]

Nature (3)

T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, Nature 502, 355 (2013).
[Crossref]

B. Spaun, P. B. Changala, D. Patterson, B. J. Bjork, O. H. Heckl, J. M. Doyle, and J. Ye, Nature 533, 517 (2016).
[Crossref]

A. Cingöz, D. C. Yost, T. K. Allison, A. Ruehl, M. E. Fermann, I. Hartl, and J. Ye, Nature 482, 68 (2012).
[Crossref]

Opt. Lett. (3)

Phys. Rev. (1)

N. F. Ramsey, Phys. Rev. 78, 695 (1950).
[Crossref]

Phys. Rev. A (2)

A. Hipke, S. A. Meek, T. Ideguchi, T. W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).
[Crossref]

A. Ozawa and Y. Kobayashi, Phys. Rev. A 86, 022514 (2012).
[Crossref]

Phys. Rev. Lett. (4)

R. Teets, J. Eckstein, and T. W. Hänsch, Phys. Rev. Lett. 38, 760 (1977).
[Crossref]

J. N. Eckstein, A. I. Ferguson, and T. W. Hänsch, Phys. Rev. Lett. 40, 847 (1978).
[Crossref]

M. M. Salour and C. Cohen-Tannoudji, Phys. Rev. Lett. 38, 757 (1977).
[Crossref]

R. K. Altmann, S. Galtier, L. S. Dreissen, and K. S. E. Eikema, Phys. Rev. Lett. 117, 173201 (2016).
[Crossref]

Other (2)

A. Hipke, S. A. Meek, G. Guelachvili, T. W. Hänsch, and N. Picqué, Conference on Lasers and Electro Optics (CLEO), OSA Postdeadline Paper Digest (online) (Optical Society of America, 2013), paper CTh5C.8.

Z. Chen, M. Yan, T. W. Hänsch, and N. Picqué, “A phase-stable dual-comb interferometer,” arXiv:1705.04214 (2017).

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (5)

Fig. 1.
Fig. 1. Principle of Doppler-free two-photon excitation dual-comb spectroscopy. See also the text for details. (a) Time-domain picture. The atomic sample is excited by two pairs of counter-propagating pulse trains of slightly different periods in a standing-wave configuration, forming two trains of standing-wave pulses. The upper-state population is modulated as a function of the variable time delay between two pulses from the two asynchronous sources. The modulation period is proportional to the atomic resonance period and can be observed as an intensity modulation in the fluorescence. (b) Frequency-domain picture. When two frequency combs of slightly different repetition frequencies simultaneously excite a two-photon transition, an intensity modulation that unambiguously identifies the optical frequency of the transition is observed in the fluorescence during decays to lower states.
Fig. 2.
Fig. 2. Experimental setup for Doppler-free dual-comb spectroscopy with two-photon excitation.
Fig. 3.
Fig. 3. Experimental dual-comb two-photon spectra of the sub-Doppler hyperfine transitions of Rb 85 and Rb 87 . (a) The span is broader than 10 THz. (b) The lines around 770.48 THz are assigned to the 5 S 1 / 2 5 D 3 / 2 transitions, and those around 770.57 THz are assigned to the 5 S 1 / 2 5 D 5 / 2 transitions.
Fig. 4.
Fig. 4. Spectrum of Doppler-free two-photon spectroscopy with a single frequency comb of 100 MHz line spacing. All the 5 S 1 / 2 5 D 3 / 2 and 5 S 1 / 2 5 D 5 / 2 transitions of Rb 85 and Rb 87 are simultaneously excited, and they appear blended and folded into a free spectral range of 100 MHz, whereas the corresponding dual-comb spectrum (Fig. 3) of the same sample unambiguously resolves the optical transitions.
Fig. 5.
Fig. 5. Magnified views of the experimental sub-Doppler dual-comb two-photon spectrum shown in Fig. 3(b). The observed full-width at half-maximum of the isolated lines is 6 MHz. The 100-MHz span in the upper part of each panel indicates the free spectral range that would be obtained with the established technique of direct frequency comb two-photon spectroscopy with a single frequency comb. (a) The lines are assigned (in ascending frequency) to the 5 S 1 / 2 F = 2 5 D 3 / 2 F = 0 ,1,2,3 transitions of Rb 87 . The signal-to-noise ratio of the 5 S 1 / 2 F = 2 5 D 3 / 2 F = 3 hyperfine line is 920. (b) The lines, which frequency is about 89 GHz apart from those shown in (a), are assigned to the 5 S 1 / 2 F = 2 5 D 5 / 2 F = 4 ,3,2,1 transitions of Rb 87 . The signal-to-noise ratio of the 5 S 1 / 2 F = 2 5 D 5 / 2 F = 4 hyperfine line is 25,000.

Metrics