Photon-Induced Near-field Electron Microscopy

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Photon-Induced Near-field Electron Microscopy (PINEM) is a variant of the Ultrafast Transmission Electron Microscopy technique and is based on the inelastic coupling between electrons and photons in presence of a surface or a nanostructure. [1] This method allows one to investigate time-varying nanoscale electromagnetic fields in an electron microscope. [2] [3]

For visible light, such inelastic coupling between electrons and light, i.e. direct absorption or emission of photons, is forbidden in free space (vacuum) since it is not possible to simultaneously conserve both energy and momentum. This constraint can be circumvented when photon momentum is broadened as a result of light being reflected or scattered from a surface or nanostructure. This process would then generate evanescently confined near-fields with a broad momentum distribution, reaching high intensities in a nanoconfined space and thus also boosting the cross section of electron-light coupling.

Theoretically, the analytical description of the phenomenon has been provided by Park et al., [4] Garcia de Abajo et al. [5] and Feist et al. [6] In these works the authors demonstrated that the strength of electron-light interaction depends on the linear coupling to the electric field projection along the electron propagation direction. In particular, Feist et al. [6] also experimentally demonstrated that the interaction process results in a coherent spectral redistribution of the electron wave packet producing Rabi oscillations of a multi-level quantum ladder in which the states are separated by the photon energy.

Particularly appealing for photonics application is the fact that the spectral, spatial and momentum distributions of the electrons subjected to such inelastic scattering process are strictly correlated with the near-field distribution mediating the electron-light coupling. The latter can be thus mapped in space and time with ultrafast electron microscopy methods, providing femtosecond movies of nanoscale fields in and around nanostructures. [7] [8] [9]

More interestingly, the PINEM method can also be used to dynamically manipulate the wave properties of the electron beam by using suitably prepared electromagnetic field configuration. In such a way, one can modulate coherently the amplitude and phase of the electron beam along both the longitudinal and the transverse directions. [6] [10] [11] [12] [13] [14] [15]

See also

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References

  1. ↑ Barwick, Brett; Flannigan, David J.; Zewail, Ahmed H. (December 2009). "Photon-induced near-field electron microscopy". Nature. 462 (7275): 902–906. doi:10.1038/nature08662. eISSN   1476-4687. ISSN   0028-0836. PMID   20016598. S2CID   4423704.
  2. ↑ Piazza, L; Lummen, T.T.A.; Quiñonez, E; Murooka, Y; Reed, B.W.; Barwick, B; Carbone, F (2 March 2015). "Simultaneous observation of the quantization and the interference pattern of a plasmonic near-field". Nature Communications. 6 (1): 6407. doi:10.1038/ncomms7407. eISSN   2041-1723. PMC   4366487 . PMID   25728197.
  3. ↑ Barwick, Brett; Zewail, Ahmed H. (2015-10-21). "Photonics and Plasmonics in 4D Ultrafast Electron Microscopy". ACS Photonics. 2 (10): 1391–1402. doi: 10.1021/acsphotonics.5b00427 . ISSN   2330-4022.
  4. ↑ S. T. Park; M. Lin; A. H. Zewail (December 2010). "Photon-induced near-field electron microscopy (PINEM): theoretical and experimental". New Journal of Physics. 12 (12): 123028. doi: 10.1088/1367-2630/12/12/123028 . S2CID   9985483.
  5. ↑ F. J. García de Abajo; A. Asenjo-Garcia; M. Kociak (April 2010). "Multiphoton Absorption and Emission by Interaction of Swift Electrons with Evanescent Light Fields". Nano Letters. 10 (5): 1859–1863. doi:10.1021/nl100613s. PMID   20415459.
  6. 1 2 3 A. Feist; K. E. Echternkamp; J. Schauss; S. V. Yalunin; S. Schäfer; C. Ropers (May 2015). "Quantum coherent optical phase modulation in an ultrafast transmission electron microscope". Nature. 521 (7551): 200–203. doi:10.1038/nature14463. PMID   25971512. S2CID   4447578.
  7. ↑ I. Madan; G. M. Vanacore; E. Pomarico; G. Berruto; R. J. Lamb; D. McGrouther; T. T. A. Lummen; T. Latychevskaia; F. J. García de Abajo; F. Carbone (May 2019). "Holographic imaging of electromagnetic fields via electron-light quantum interference". Science Advances. 5 (5): eaav8358. doi:10.1126/sciadv.aav8358. PMC   6499551 . PMID   31058225.
  8. ↑ Wang, Kangpeng; Dahan, Raphael; Shentcis, Michael; Kauffmann, Yaron; Ben Hayun, Adi; Reinhardt, Ori; Tsesses, Shai; Kaminer, Ido (2020-06-04). "Coherent interaction between free electrons and a photonic cavity". Nature. 582 (7810): 50–54. arXiv: 1908.06206 . doi:10.1038/s41586-020-2321-x. ISSN   0028-0836. PMID   32494081. S2CID   219281767.
  9. ↑ Kfir, Ofer; Lourenço-Martins, Hugo; Storeck, Gero; Sivis, Murat; Harvey, Tyler R.; Kippenberg, Tobias J.; Feist, Armin; Ropers, Claus (2020-06-04). "Controlling free electrons with optical whispering-gallery modes". Nature. 582 (7810): 46–49. arXiv: 1910.09540 . doi:10.1038/s41586-020-2320-y. ISSN   0028-0836. PMID   32494079. S2CID   204823876.
  10. ↑ Morimoto, Yuya; Baum, Peter (27 November 2017). "Diffraction and microscopy with attosecond electron pulse trains". Nature Physics. 14 (3): 252–256. doi:10.1038/s41567-017-0007-6. eISSN   1745-2481. ISSN   1745-2473. S2CID   125210956.
  11. ↑ Kozák, M.; Eckstein, T.; Schönenberger, N.; Hommelhoff, P. (9 October 2017). "Inelastic ponderomotive scattering of electrons at a high-intensity optical travelling wave in vacuum". Nature Physics. 14 (2): 121–125. arXiv: 1905.05240 . doi:10.1038/nphys4282. eISSN   1745-2481. ISSN   1745-2473. S2CID   126006282.
  12. ↑ Priebe, Katharina E.; Rathje, Christopher; Yalunin, Sergey V.; Hohage, Thorsten; Feist, Armin; Schäfer, Sascha; Ropers, Claus (December 2017). "Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy". Nature Photonics. 11 (12): 793–797. arXiv: 1706.03680 . doi:10.1038/s41566-017-0045-8. ISSN   1749-4885. S2CID   119105731.
  13. ↑ Vanacore, G. M.; Madan, I.; Berruto, G.; Wang, K.; Pomarico, E.; Lamb, R. J.; McGrouther, D.; Kaminer, I.; Barwick, B.; García de Abajo, F. Javier; Carbone, F. (12 July 2018). "Attosecond coherent control of free-electron wave functions using semi-infinite light fields". Nature Communications. 9 (1): 2694. doi:10.1038/s41467-018-05021-x. eISSN   2041-1723. PMC   6043599 . PMID   30002367.
  14. ↑ K. E. Echternkamp; A. Feist; S. Schäfer; C. Ropers (August 2016). "Ramsey-type phase control of free-electron beams". Nature Physics. 12 (11): 1000–1004. arXiv: 1605.00534 . doi:10.1038/NPHYS3844. S2CID   119214197.
  15. ↑ G. M. Vanacore; G. Berruto; I. Madan; E. Pomarico; P. Biagioni; R. J. Lamb; D. McGrouther; O. Reinhardt; I. Kaminer; B. Barwick; H. Larocque; V. Grillo; E. Karimi; F. J. García de Abajo; F. Carbone (May 2019). "Ultrafast generation and control of an electron vortex beam via chiral plasmonic near fields". Nature Materials. 18 (6): 573–579. doi:10.1038/s41563-019-0336-1. PMID   31061485. S2CID   119186105.
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