Recently a new electro-optic detection system has been used to characterize the temporal and spatial distribution of free-space broadband, pulsed electromagnetic radiation (THz beams). This detection system, which uses an electro-optic crystal sensor, provides diffraction-limited spatial resolution, femtosecond temporal resolution, DC-THz spectral bandwidth, and sub¬milli-volt per centimeter field detectability. The sensitivity and bandwidth of the electro-optic detectors are comparable or superior to conventional ultrafast photo-conductive dipole antennas and liquid helium cooled bolometers. Advantages intrinsic to electro-optic detection include nonresonant frequency response, large detector area, high scan rate, low optical probe power, and large linear dynamic range.
by X.-C. Zhang and Q. Wu, Rensselaer Polytechnic Institute, Troy, N.Y.