Terahertz generation by means of optical lasers

Generation of high-power radiation in terahertz frequency range 0.3 – 10 THz is a fast developing research area attracting considerable interest over the past years due to its important applications in spectroscopy, communication, biomedical imaging and tomography. A brief review of laser-based generation methods is presented, starting from the schemes of resonance laser excitation of photoconductive materials, organic molecules and ionized gases, and proceeding with more detailed description of non-resonance schemes of optical rectification and difference frequency generation in materials with high optical nonlinearity. Recent progress achieved in both groups of methods is compared.