Coherent detection of freely propagating terahertz radiation by electro-optic sampling

We report the demonstration of an electro-optic sampling technique that allows for the detection of freely propagating terahertz radiation. Coherent sampling is performed in a poled polymer device that is physically separated from the emitter. The poling electrodes in the sampling element are found to have an integrating effect on the incident terahertz field. The shot noise limited minimum detectable field in the polymer is 100 (mV/cm)/root Hz. We discuss methods by which the sensitivity may be significantly enhanced. (C) 1996 American Institute of Physics.