Nonlinear diffraction in asymmetric dielectric metasurfaces

Jonathan Bar-David, Uriel Levy*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Metasurfaces provide new and promising mechanisms with which to control and manipulate light at the nanoscale. While most metasurfaces are designed to operate in the linear regime, it was recently shown that such metasurfaces may also generate nonlinear signals by manipulation of the higher-order susceptibility terms. As such, metasurfaces can generate additional harmonics without the need for light propagation, as typically occurs in nonlinear crystals. While such demonstrations typically rely on the nonlinear properties of metals, we hereby report the design, fabrication, and experimental characterization of a resonant dielectric metasurface made of amorphous silicon to create and manipulate second harmonic light and control its diffraction patterns. As shown in the paper, the second harmonic generation of light follows selection rules that rely on the asymmetry of the meta-atom. Given the fact that silicon crystals are centrosymmetric, the generation of the second harmonic signal in amorphous silicon is intriguing. In fact, the second harmonic signal is generated mostly from the surface of the meta-atom. It is the use of nanostructures that increases the surface-to-volume ratio and enables second harmonic generation. Additionally, the meta-atom is designed to exploit its spectral resonances in the principal and the second harmonic frequencies for providing electromagnetic field enhancement, which assists in boosting the generation of second harmonic signals.

Original languageAmerican English
Pages (from-to)1044-1051
Number of pages8
JournalNano Letters
Volume19
Issue number2
DOIs
StatePublished - 13 Feb 2019

Bibliographical note

Publisher Copyright:
© 2019 American Chemical Society.

Keywords

  • Dielectric metasurfaces
  • Metasurfaces
  • Nonlinear optics
  • Phase-gradient metasurfaces

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