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We present the results of the first intercomparison of the rise-time calibration of a 50-GHz sampling oscilloscope between Physikalisch-Technische Bundesanstalt, Germany, and National Physical Laboratory, U.K. (EUROMET project 641). Rise-times between 6.0 and 6.6 ps were obtained using optoelectronic techniques. Detailed uncertainty budgets are given, which yield typical rise-time uncertainties of 1.2 ps. The absolute values of the degree of equivalence are ≤ 0.3 ps with an expanded uncertainty of 1.0 ps and, thus, validate the experimental techniques. [ABSTRACT FROM AUTHOR]

We present a method that allows for the simultaneous generation and detection of ultrashort voltage pulses, which propagate on a planar transmission line, in the same material with laser pulses of the same wavelength. The generation is accomplished by exciting band-tail states below the fundamental bandgap of a low-temperature grown GaAs layer, while the detection takes advantage of the electro-optic effect in the GaAs material. This simple scheme considerably enhances previous measurement techniques and is capable of generating and measuring frequencies exceeding 1 THz. The optimum wavelength for the combined generation and detection technique is found at ∼900 nm. [ABSTRACT FROM AUTHOR]