THz generation using extrinsic photoconductivity at 1550 nm

1550-nm pulses from a fiber-mode-locked laser are used to drive an ErAs: GaAs photoconductive switch, resulting in easily measured THz radiation with average broadband (similar to 0.1 to 1.0 THz) power of approximate to 0.1 mW. The new THz switching mechanism is attributed to fast extrinsic photoconductivity that generates photocarriers (probably electrons) from the ErAs nanoparticles embedded in the material with a lifetime of similar to 0.45 ps (354 GHz bandwidth). This is the first known demonstration of useful THz power generation by extrinsic photoconductivity. (C) 2012 Optical Society of America