Nonlinear photoconductivity characteristics of antenna activated by 80-picosecond optical pulses

We report nonlinear characteristics of the radiated field, generated by a gigahertz photoconducting antenna, versus the bias field. For semi-insulating GaAs a saturation phenomenon was observed when the photocarrier population was below 3×10/sup 16//cm
³
. A set of characteristic curves was obtained as a function of bias field (<12 kV/cm) and optical fluence (<30 μJ/cm
²
). Fe-doped InP and LTG-GaAs were also investigated for comparisons. The experimental data obtained can be qualitatively analyzed by the bias field depletion effect and electron intersub-band scattering mechanism. This technique can also be utilized as a convenient tool to study the transient electronic behaviour of the photocarriers in the picosecond regime.