High-yield, ultrafast, surface plasmon-enhanced, Au nanorod optical field electron emitter arrays

Richard G. Hobbs, Yujia Yang, Arya Fallahi, Philip D. Keathley, Eva De Leo, Franz X. Kärtner, William S. Graves, Karl K. Berggren

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

Here we demonstrate the design, fabrication, and characterization of ultrafast, surface-plasmon enhanced Au nanorod optical field emitter arrays. We present a quantitative study of electron emission from Au nanorod arrays fabricated by highresolution electron-beam lithography and excited by 35 fs pulses of 800 nm light. We present accurate models for both the optical field enhancement of Au nanorods within high-density arrays, and electron emission from those nanorods. We have also studied the effects of surface plasmon damping induced by metallic interface layers at the substrate/nanorod interface on near-field enhancement and electron emission. We have identified the peak optical field at which the electron emission mechanism transitions from a 3-photon absorption mechanism to strong-field tunneling emission. Moreover, we have investigated the effects of nanorod array density on nanorod charge yield, including measurement of space-charge effects. The Au nanorod photocathodes presented in this work display 100-1000 times higher conversion efficiency relative to previously reported UV triggered emission from planar Au photocathodes. Consequently, the Au nanorod arrays triggered by ultrafast pulses of 800 nm light in this work may outperform equivalent UV-triggered Au photocathodes, while also offering nanostructuring of the electron pulse produced from such a cathode, which is of interest for X-ray free-electron laser (XFEL) development where nanostructured electron pulses may facilitate more efficient and brighter XFEL radiation. (Figure Presented).

Original languageEnglish (US)
Pages (from-to)11474-11482
Number of pages9
JournalACS nano
Volume8
Issue number11
DOIs
StatePublished - Nov 25 2014
Externally publishedYes

Keywords

  • Field-enhancement
  • Lightwave electronics
  • Nano-optics
  • Nanorods
  • Plasmons
  • Strong-field tunneling
  • Ultrafast electron emission

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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  • Cite this

    Hobbs, R. G., Yang, Y., Fallahi, A., Keathley, P. D., De Leo, E., Kärtner, F. X., Graves, W. S., & Berggren, K. K. (2014). High-yield, ultrafast, surface plasmon-enhanced, Au nanorod optical field electron emitter arrays. ACS nano, 8(11), 11474-11482. https://doi.org/10.1021/nn504594g