High accuracy terahertz time‐domain system for reliable characterization of photoconducting antennas

We report on a terahertz (THz) time‐domain system to characterize photoconductive THz emitters and detectors, that is designed for highest reproducibility. This system is excellently suited for studying the performance of THz sources and detectors in a systematic manner, either by varying the substrate materials or the geometrical parameters of metallic antenna contacts building a photoconductive switch. After confirming the reproducibility and stability of the system with errors of only 1.9% (over 3 h) and 2.6% (over 9 days), we use the system to compare the performance of five low temperature grown (LT) GaAs wafers with growth temperatures between 200°C and 300°C.