128 channel THz ultrashort pulse system

For THz ultrashort pulse imaging a high scan speed in combination with a high signal/noise ratio is required. Several methods have been presented to accelerate the classical one channel THz pulse detection. For example 2D electrooptic sampling provides a short scan time, but the signal/noise ratio is low and there is a need for an expensive low repetition fs-laser amplifier system to generate high energy THz pulses. This paper presents a THz ultrashort pulse system with 128 emission and detection channels based on photoconductive antennas. Both emitter and detector have the same structure consisting of dipole antennas with electrode distance of 40 mum and a gap width of 7.5 mum. The efficient excitation of such a multichannel dipole structure is done by microlens array for 16 detection channels. The presented method is highly scalable and in future even 2D sensors based on photoconductive antennas and microlens arrays are possible.