P. Kužel has introduced the terahertz (THz) time-domain spectroscopy in the Czech Republic in the late 90s. Since that time the THz group at FZU has built four related experimental setups and obtained a large number of results in the field of soft mode spectroscopy in ferroelectrics and related materials, in photonic crystals and metamaterials for the THz range and in the area of ultrafast photoconductivity of semiconductors. In particular, P. Kužel currently devotes a large effort to investigation of ultrafast charge carrier transport in semiconductor nanostructures. In this context, the importance of THz spectroscopy stems from the non-contact character of measurements; in addition, owing to its high frequency and broadband character, it allows us to characterize charge transport properties within individual nanoobjects and also among them. Probing of ultrafast charge dynamics after photoexcitation is possible thanks to the sub-picosecond time resolution.
