Detectors and sources for ultrabroadband electro-optic sampling: Experiment and theory

A detailed calculation of the amplitude and phase response of ultrathin ZnTe and GaP electro-optic sensors is presented. We demonstrate that the inclusion of the dispersion of the second-order nonlinearity is essential. Significant structures in experimental data can be explained by the theoretical response function. Correcting for the detector characteristics, we determine the precise shape of electromagnetic transients with a time resolution of 20 fs. In addition, we show that ultrafast transport of photocarriers in semiconductors can act as an efficient source for coherent electromagnetic radiation covering the entire far-to-mid-infrared regime. (C) 1999 American Institute of Physics. [S0003-6951(99)02711-4].