All–optoelectronic continuous–wave terahertz systems

We discuss the optoelectronic generation and detection of continuous–wave terahertz (THz) radiation by the mixing of visible/near–infrared laser radiation in photoconductive antennas. We review attempts to reach higher THz output–power levels by reverting from mobility–lifetime–limited photomixers to transit–time–limited p–i–n photodiodes. We then describe our implementation of a THz spectroscopy and imaging–measurement system and demonstrate its imaging performance with several examples. Possible application areas of THz imaging in the biomedical field and in surface characterization for industrial purposes are explored.

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