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 x 10(16)/cm(3). A set of characteristic curves was obtained as a function of bias field (< 12 KV/cm) and optical fluence (< 30 mu J/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: behavior of the photocarriers in the picosecond regime.