Spatio-temporal imaging of THz pulses

We report the use of an optoelectronic system for the measurement of THz pulses by use of chirped pulse technology. This novel system measures the spatio-temporal distribution of a free-space pulsed radiation with an unprecedented data acquisition rate. Using a linearly-chirped optical probe pulse in free-space for electro-optic measurements, a temporal waveform of a co-propagating terahertz (THz) field is linearly encoded onto the frequency spectrum of the optical probe pulse, and then decoded by dispersing the probe beam from a grating to a detector array. Acquisition of picosecond THz field pulses without using mechanical time-delay devices has been achieved. A single-shot electro-optic measurement of the temporal waveform of a THz pulse has been demonstrated. Unparalleled by other THz sampling techniques, this single-shot method provides what is believed to be the highest possible data-acquisition rate.