Optically defined plasmonic waveguides in crystalline semiconductors at optical frequencies

High intensity optical excitation to transform a crystalline semiconductor into a plasmonic metal at near-infrared wavelengths is theoretically investigated. A calculated intensity of 51.46 GW/cm super(2) is sufficient to transformGaAs into metal at 1.55 mu m to support plasmonic modes. A practical nanoscale plasmonic gap waveguide is designed based on the GaAs/GaN materials system, demonstrating the capability of obtaining plasmonic waveguiding by high intensity optical excitation. The propagation characteristics of the plasmonic gap mode in the designed waveguide can be dynamically tuned over a broad range of values by varying the intensity of the pump excitation using modest average powers between 15 and 75 mW.