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Tracking the motion of charges in a terahertz light field by femtosecond X-ray diffraction

Abstract

In condensed matter, light propagation near resonances is described in terms of polaritons, electro-mechanical excitations in which the time-dependent electric field is coupled to the oscillation of charged masses1,2. This description underpins our understanding of the macroscopic optical properties of solids, liquids and plasmas, as well as of their dispersion with frequency. In ferroelectric materials, terahertz radiation propagates by driving infrared-active lattice vibrations, resulting in phonon-polariton waves. Electro-optic sampling with femtosecond optical pulses3,4,5 can measure the time-dependent electrical polarization, providing a phase-sensitive analogue to optical Raman scattering6,7. Here we use femtosecond time-resolved X-ray diffraction8,9,10, a phase-sensitive analogue to inelastic X-ray scattering11,12,13, to measure the corresponding displacements of ions in ferroelectric lithium tantalate, LiTaO3. Amplitude and phase of all degrees of freedom in a light field are thus directly measured in the time domain. Notably, extension of other X-ray techniques to the femtosecond timescale (for example, magnetic or anomalous scattering) would allow for studies in complex systems, where electric fields couple to multiple degrees of freedom14.

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Figure 1: Excitation of phonon polaritons in LiTaO3.
Figure 2: Optical pump, X-ray diffraction probe experimental apparatus.
Figure 3: Measurement of the time-dependent change in the 006 diffracted intensity.

References

  1. Mills, D. L. & Burstein, E. Polaritons: the electromagnetic modes of media. Rep. Prog. Phys. 37, 817–926 (1974)

    ADS  CAS  Article  Google Scholar 

  2. Barker, A. S. Jr & Loudon, R. Response functions in the theory of Raman scattering by vibrational and polariton modes in dielectric crystals. Rev. Mod. Phys. 44, 18–47 (1972)

    ADS  CAS  Article  Google Scholar 

  3. Auston, D. H., Cheung, K. P., Valdamanis, J. A. & Kleinman, D. Cherenkov radiation from femtosecond optical pulses in electro-optic media. Phys. Rev. Lett. 53, 1555–1558 (1984)

    ADS  CAS  Article  Google Scholar 

  4. Wahlstrand, J. K. & Merlin, R. Cherenkov radiation emitted by ultrafast laser pulses and the generation of coherent polaritons. Phys. Rev. B 68, 054301 (2003)

    ADS  Article  Google Scholar 

  5. Crimmins, T. F., Stoyanov, N. S. & Nelson, K. A. Heterodyned impulsive stimulated Raman scattering of phonon-polaritons in LiTaO3 and LiNbO3 . J. Chem. Phys. 117, 2882–2896 (2002)

    ADS  CAS  Article  Google Scholar 

  6. Dougherty, T. P. et al. Femtosecond resolution of soft mode dynamics in structural phase transitions. Science 258, 770–774 (1992)

    ADS  CAS  Article  PubMed  Google Scholar 

  7. Stevens, T. E., Wahlstrand, J. K., Kuhl, J. & Merlin, R. Cherenkov radiation at speeds below the light threshold: phonon assisted phase matching. Science 291, 627–630 (2001)

    ADS  CAS  Article  PubMed  Google Scholar 

  8. Rischel, C. et al. Femtosecond time-resolved X-ray diffraction from laser heated organic films. Nature 390, 490–492 (1997)

    ADS  CAS  Article  Google Scholar 

  9. Cavalleri, A. et al. Femtosecond structural dynamics in VO2 during an ultrafast solid-solid phase transition. Phys. Rev. Lett. 87, 237401 (2001)

    ADS  CAS  Article  PubMed  Google Scholar 

  10. Lindenberg, A. M. et al. Atomic scale visualization of inertial dynamics. Science 308, 392–395 (2005)

    ADS  CAS  Article  PubMed  Google Scholar 

  11. Cavalleri, A. et al. Anharmonic lattice dynamics in germanium measured with ultrafast x-ray diffraction. Phys. Rev. Lett. 85, 586–589 (2000)

    ADS  CAS  Article  PubMed  Google Scholar 

  12. Lindenberg, A. M. et al. Time-resolved X-ray diffraction from coherent phonons during a laser-induced phase transition. Phys. Rev. Lett. 84, 111–114 (2000)

    ADS  CAS  Article  PubMed  Google Scholar 

  13. Bargheer, M. et al. Coherent atomic motions in a nanostructure studied by femtosecond x-ray diffraction. Science 306, 1771–1773 (2004)

    ADS  CAS  Article  PubMed  Google Scholar 

  14. Kimel, A. V. et al. Ultrafast non-thermal control of magnetization by instantaneous photo-magnetic pulses. Nature 435, 655–657 (2005)

    ADS  CAS  Article  PubMed  Google Scholar 

  15. Bakker, H. J., Hunsche, S. & Kurz, H. Time-resolved study of phonon polaritons in LiTaO3 . Phys. Rev. B 48, 13524–13537 (1993)

    ADS  CAS  Article  Google Scholar 

  16. Sokolowski-Tinten, K. et al. Femtosecond X-ray measurement of coherent lattice vibrations near the Lindemann stability limit. Nature 422, 287–289 (2003)

    ADS  CAS  Article  PubMed  Google Scholar 

  17. Stoyanov, N. S., Ward, D. W., Feurer, Th. & Nelson, K. A. Terahertz polariton propagation in patterned materials. Nature Mater. 1, 95–98 (2002)

    ADS  CAS  Article  Google Scholar 

  18. Zholents, A. A. & Zolotorev, M. S. Femtosecond X-ray pulses of synchrotron radiation. Phys. Rev. Lett. 76, 912–915 (1996)

    ADS  CAS  Article  PubMed  Google Scholar 

  19. Schoenlein, R. W. et al. Generation of femtosecond pulses of synchrotron radiation. Science 287, 2237–2240 (2000)

    ADS  CAS  Article  PubMed  Google Scholar 

  20. Cavalleri, A. et al. Band selective measurements of electron dynamics in VO2 using femtosecond near edge X-ray absorption. Phys. Rev. Lett. 95, 067405 (2005)

    ADS  CAS  Article  PubMed  Google Scholar 

  21. Feurer, T., Vaughan, J. C. & Nelson, K. A. Spatiotemporal coherent control of lattice vibrational waves. Science 299, 374–377 (2003)

    ADS  CAS  Article  PubMed  Google Scholar 

  22. Kimura, T. et al. Magnetic control of ferroelectric polarization. Nature 426, 55–58 (2003)

    ADS  CAS  Article  PubMed  Google Scholar 

  23. Lottermoser, Th. et al. Magnetic phase control by an electric field. Nature 430, 541–544 (2004)

    ADS  CAS  Article  PubMed  Google Scholar 

  24. Kimel, A. V., Kirilyuk, A., Tsvetkov, A., Pisarev, R. V. & Rasing, Th. Laser-induced ultrafast spin re-orientation in the antiferromagnet TmFeO3 . Nature 429, 850–853 (2004)

    ADS  CAS  Article  PubMed  Google Scholar 

  25. Bucksbaum, P. H. & Merlin, R. The phonon Bragg switch: a proposal to generate sub-picosecond x-ray pulses. Solid State Commun. 111, 535–539 (1999)

    ADS  CAS  Article  Google Scholar 

  26. Nazarkin, A., Uschman, I., Förster, E. & Sauerbrey, R. High order Raman scattering of X-rays by optical phonons and generation of ultrafast X-ray transients. Phys. Rev. Lett. 93, 207401 (2004)

    ADS  CAS  Article  PubMed  Google Scholar 

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Acknowledgements

We thank M. Khalil for her help during data acquisition. We are grateful to J. S. Wark for discussions, as well as for sharing the results of dynamic diffraction simulations for LiTaO3. We thank K. Sokolowski-Tinten, R. Merlin, D. Reis and S. Hooker for many discussions, suggestions and for critical reading of our manuscript. Help by N. Tamura with the measurement of static Laue patterns in LiTaO3 is also gratefully acknowledged. Experiments at LBNL were supported by the Director, Office of Science, Office of Basic Energy Sciences, Division of Materials Science and Engineering Division, of the US Department of Energy. Work at the University of Oxford was supported by the European Science Foundation through a European Young Investigator Award. S.W. acknowledges receipt of a graduate scholarship from the UK Engineering and Physical Sciences Research Council. Simulation work at MIT was funded by the US National Science Foundation.

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Correspondence to A. Cavalleri.

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Cavalleri, A., Wall, S., Simpson, C. et al. Tracking the motion of charges in a terahertz light field by femtosecond X-ray diffraction. Nature 442, 664–666 (2006). https://doi.org/10.1038/nature05041

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