Enhanced nonlinear refractive index in epsilon-near-zero materials

L. Caspani, R.P.M. Kaipurath, M. Clerici, M. Ferrera, T. Roger, J. Kim, N. Kinsey, M. Pietrzyk, A. Di Falco, V. M. Shalaev, A. Boltasseva, D. Faccio

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222 Citations (Scopus)
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New propagation regimes for light arise from the ability to tune the dielectric permittivity to extremely low values. Here, we demonstrate a universal approach based on the low linear permittivity values attained in the ε-near-zero (ENZ) regime for enhancing the nonlinear refractive index, which enables remarkable light-induced changes of the material properties. Experiments performed on Al-doped ZnO (AZO) thin films show a sixfold increase of the Kerr nonlinear refractive index (n2) at the ENZ wavelength, located in the 1300 nm region. This in turn leads to ultrafast light-induced refractive index changes of the order of unity, thus representing a new paradigm for nonlinear optics.
Original languageEnglish
Article number233901
Number of pages5
JournalPhysical Review Letters
Issue number23
Publication statusPublished - 8 Jun 2016


  • nonlinear optical behaviour
  • nonlinear refractive index
  • nonlinear optics


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