Two-dimensional electro-optic imaging of THz beams

We report on a novel electro-optic sampling system for real-time terahertz (THz) imaging applications. By illuminating a 6×8 mm2 ZnTe crystal with a 300 μW optical sampling beam and detecting the beam with a digital CCD camera, we achieved time-resolved images of pulsed far-infrared radiation emitted from an unbiased GaAs wafer. At the focal point of the peak far-infrared field, the THz beam diameter is approximately 0.75 mm (full width at half-maximum). The temporal and spatial resolutions of this imaging system are mainly limited by the laser pulse duration and the diffraction limit of the THz beam, respectively.