THz generation using extrinsic photoconductivity at 1550 nm

Abstract

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 (~0.1 to 1.0 THz) power of ≈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 ~0.45 ps (354 GHz bandwidth). This is the first known demonstration of useful THz power generation by extrinsic photoconductivity.