Ultrafast nonlinear effects in hydrogenated amorphous silicon wire waveguide

Opt Express. 2010 Mar 15;18(6):5668-73. doi: 10.1364/OE.18.005668.

Abstract

We, for the first time, present the ultrafast optical nonlinear response of a hydrogenated amorphous silicon (a-Si:H) wire waveguide using femtosecond pulses. We show cross-phase and cross-absorption modulations measured using the heterodyne pump-probe method and estimate the optical Kerr coefficient and two-photon absorption coefficient for the amorphous silicon waveguide. The pumping energy of 0.8 eV is slightly lower than that required to achieve two-photon excitation at the band gap of a-Si:H (approximately 1.7 eV). An ultrafast response of less than 100 fs is observed, which indicates that the free-carrier effect is suppressed by the localized states in the band gap.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Equipment Design
  • Equipment Failure Analysis
  • Hydrogen / chemistry*
  • Nonlinear Dynamics
  • Refractometry / instrumentation*
  • Silicon / chemistry*

Substances

  • Hydrogen
  • Silicon