Ultrafast far-infrared GaAs/AlGaAs photon drag detector in microwave transmission line topology.

A novel room temperature GaAs/AlGaAs multiquantum-well photon drag detector operating in the 10 mu m wavelength range and designed as a microstrip transmission line has been developed. Total-reflection angle incoupling, using a Ge prism, provides velocity matching between the optical and electrical pulses. Signal transients with 10 ps rise and fall time have been measured using 2 ps pulses from a free electron laser. From the wavelength dependence of the photon drag signal the room temperature momentum relaxation times in the first and second electron subband can be determined.