New sources and schemes for terahertz spectroscopy

We review recent advances in terahertz spectroscopy and the generation of THz waves. This includes i) a terahertz time domain spectrometer which does not rely on an external delay line but employs a single ultrafast laser with an adjustable pulse repetition rate, ii) an inexpensive spectroscopy approach termed terahertz quasi-time-domain spectroscopy, iii) THz antennas for telecom wavelength with improved efficiency and iv) a new room temperature source which is capable of emitting continuous wave THz radation at mW power levels.