Free Carrier Induced Spectral Shift for GaAs Filled Metallic Hole Arrays.

摘要

For a GaAs filled metallic hole array on a pre-epi GaAs substrate, the free carriers, generated by three-photon absorption (3PA) assisted by strongly enhanced local fields, reduce the refractive index of GaAs in approximately 200-nm thick active area through band filling and free carrier absorption. Therefore, the surface plasma wave (SPW) resonance, and the related second harmonic (SH) spectrum blue shifts with increasing fluence For the plasmonic structure on a substrate with surface defects, free carrier recombination dominates. The band gap emission spectral peak wavelength decreases 10-nm with increasing fluence, showing the transition from nonradiative-, at low excitation, to bimolecular- recombination at high carrier concentrations.