Measurement of free-space terahertz pulses via long-lifetime photoconductors

Abstract

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 μm2), GaAs based antennas exhibit a higher responsivity and signal-to-noise ratio than typical antennas based on radiation-damaged silicon-on-sapphire.