Extrinsic photoconductivity at 1550 nm and 1030 nm for THz Generation

Pulses from a 1550 and 1030 nm fiber-mode-locked laser are used to drive an ErAs:GaAs photoconductive switch, resulting in extrinsic photoconductivity and useful levels of THz (~100 μW) with the 1550-nm laser drive, but not with the 1030-nm laser. This finding supports the recent discovery that extrinsic photoconductivity is a useful mechanism in ErAs:GaAs, but the THz generation is sensitive to the specific laser drive wavelength.