Low-temperature-grown GaAs (LT-GaAs)-based Fabry-Pérot cavity photoconductors, designed for RF and THz optoelectronics applications using1550 nm lasers, are studied. The sub-sampling of continuous waves at frequencies up to 300 GHz is presented. The duty-cycle-limited conversion losses measured up to 67 GHz show that this GaAs-based photoconductor behaves as a nearly perfect photoswitch controlled by a 1550 nm pulsed laser.

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Ultrafast photoconductors using GaAs implanted by low energy N+ ions (<55 keV) are fabricated and characterized up to 320 GHz by means of a photomixing experiment. Around 90 μW of output power was obtained at 290 GHz with a 2-μm-diameter photoconductor based on a 160-nm-thick GaAs layer implanted with a main dose of 1.1 × 1012 cm−2 and a subsequent annealing at 600 °C. These performances are similar to those obtained with LT-GaAs photoconductors having same electrodes geometry. Besides, it is shown that the frequency dependence of the output power is not correlated to the carrier lifetime as measured by time-resolved photoreflectance.