Antennas based on commercially available GaAs as a photoconductor with a subnanosecond photocarrier lifetime have been used to detect subpicosecond free‐space electromagnetic radiation (THz pulses). At low optical gating intensities (≤1 mW/100 &mgr;m2), GaAs based antennas exhibit a higher responsivity and signal‐to‐noise ratio than typical antennas based on radiation‐damaged silicon‐on‐sapphire. ©1995 American Institute of Physics.