Ultrafast All-Optical Switching with Magnetic Resonances in Nonlinear Dielectric Nanostructures

Nano Lett. 2015 Oct 14;15(10):6985-90. doi: 10.1021/acs.nanolett.5b02989. Epub 2015 Sep 29.

Abstract

We demonstrate experimentally ultrafast all-optical switching in subwavelength nonlinear dielectric nanostructures exhibiting localized magnetic Mie resonances. We employ amorphous silicon nanodisks to achieve strong self-modulation of femtosecond pulses with a depth of 60% at picojoule-per-disk pump energies. In the pump-probe measurements, we reveal that switching in the nanodisks can be governed by pulse-limited 65 fs-long two-photon absorption being enhanced by a factor of 80 with respect to the unstructured silicon film. We also show that undesirable free-carrier effects can be suppressed by a proper spectral positioning of the magnetic resonance, making such a structure the fastest all-optical switch operating at the nanoscale.

Keywords: Nonlinear optics; all-optical switching; femtosecond optics; metasurfaces; optical magnetism; silicon photonics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Magnetics*
  • Nanostructures*
  • Photons