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Terahertz Radiometry

Working Group 7.34


Poster WG 7.34

The central task of the working group is the quantitative measurement of the radiant power of electromagnetic radiation in the far infrared spectral range, which is also known as the terahertz range. Being unique in the world, the service of calibrating the spectral responsivity of THz detectors traceable to the International System of Units (SI) actually covers the frequency range from 700 GHz to 5 THz.

The lowest possible uncertainties are achieved at a measurement facility with a far infrared molecular gas laser. It is optically pumped by a frequency-stabilized CO2-laser and produces tunable monochromatic radiation of rotational transitions of the applied molecular gas. Terahertz radiometry helps to bridge the metrological gap between the electronic power measurement at ultra-high frequencies and radiometry at very long wavelengths. For instance, it is important for novel noncontact techniques of nondestructive material testing or new technologies of homeland security (e.g. body and mail scanners).

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  • Design, development and characterization of novel spectrally flat THz detectors used as radiometric reference detectors for terahertz time-domain spectrometers (THz-TDS) in cooperation with industry partners
  • Realizing the spectral responsivity at a frequency range extended below 700 GHz
  • Comparing the wave-guide-based power measurement technique at high frequencies Opens internal link in current window(WG 2.22) with the radiant THz power measurement
  • Characterization of a new measurement facility for determining optical properties by reflection and transmission measurements in the spectral range spanning from 0.1 THz to 1 THz by means of a fiber-based time-domain spectroscopy (THz-TDS) system
  • Cooperation with a industry partner to develop and validate a reference material for characterizing reflection and transmission measurements by means of THz-TDS systems
  • Compiling VDI/VDE-GMA directives of terahertz systems by the German technical committee FA 8.17 Terahertz Systems

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 Calibration and measurements capabilities in WG 7.34:

  • Measuring the spectral responsivity with respect to radiant power of detectors in the frequency range spanning from 1 THz to 5 THz
  • Measuring the spatial uniformity and the power variation (linearity) of the spectral responsivity of THz detectors


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