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High-brightness terahertz beams characterized with an ultrafast detector

van Exter, Martin
Fattinger, Ch.
Grischkowsky, D.
We have significantly improved the emission and detection of electromagnetic beams of single-cycle 0.5 THz pulses, through the use of new dipolar antenna structures. The frequency response was extended to well beyond the 1THz, and the beam power was increased by more than 15 times. The antennas were located at the foci of sapphire lenses and were photoconductively driven by ultrafast laser pulses. An additional collimation by a paraboloidal mirror produced a beam with a 25 mrad divergence, and a subsequent focusing by a second identical mirror improved the coupling between the transmitting and receiving antenna by orders of magnitude.