Download or read book Coherent Thz Sources: Present Status and the Potential of New Approaches written by and published by . This book was released on 1995 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main aim of this report is to give a state of the art view of the different approaches toward the realisation of THz sources. The report concentrates on semiconductor based sources which can be integrated in MMICs. At the lower end of the spectrum in the inn to 700 GHz range several commercially available semiconductor sources operate at room temperature. Field effect transistors and oscillators such as IMPATT diodes or Gunn oscillators have reached frequencies between 100 and 200 GHz with power levels well above the 100 mW range. Due to the advances in semiconductor growth techniques new concepts for the realisation of THz sources can be persued. The most interesting concept is the Voltage driven Bloch oscillator, which would lead to a coherent and widely tuneable source. A second concept is the intersubband laser already demonstrated for infrared frequencies. A quite promising approach is the current induced generation of collective excitations - plasma waves - to generate tuneable radiation in the THz region. This concept combines classical methods of carrier bunching with confinement concepts and the shaping of bandstructures. Finally THz radiation generated by short pulses offers also a new source with a wide frequency range for coherent spectroscopy. (AN).