Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Field-effect transistor based detector for measuring power fluctuations of 4.75-THz quantum-cascade laser-generated radiation

TeraFET detector for measuring power fluctuations of radiation from a 4.75-THz QCL
: Zdanevicius, J.; Cibiraitė, D.; Ikamas, K.; Bauer, M.; Matukas, J.; Lisauskas, A.; Richter, H.; Krozer, V.; Hübers, H.-W.; Roskos, H.G.

IEEE Microwave Theory and Techniques Society:
29th International Symposium on Space Terahertz Technology (ISSTT 2018) : Pasadena, California, USA, 26-28 March 2018
Red Hook, NY: Curran, 2018
ISBN: 978-1-5108-7474-9
International Symposium on Space Terahertz Technology (ISSTT) <29, 2018, Pasadena/Calif.>
Fraunhofer ITWM ()

n order to understand the formation of massive young stars, observation of a major coolant of dense interstellar medium, neutral atomic oxygen which has a fine-structure line at 4.7448 THz, is an important task. It requires high-sensitivity and high-resolution spectroscopy systems in the terahertz (THz) frequency range. One of such systems is in the Stratospheric Observatory For Infrared Astronomy (SOFIA). It essentially requires stable local oscillator (LO) source for heterodyne detection. Therefore, we explore a field-effect transistor based THz detector (TeraFET) with an integrated resonant patch antenna fabricated in commercially available standard 90-nm CMOS technology. At 4.75 THz, the detector exhibits an area-normalized minimal noise-equivalent power (NEP) of 404 pW/Hz and a maximum responsivity of 75 V/W where the effective area is 1750 µm2 and directivity reaches 7.4 dBi. These sensitivity and responsivity values contributes to the state of the art for room-temperature electronic detectors operating at around 4.7 THz. We demonstrate experimentally, that the TeraFET detector can monitor the intensity of THz QCL radiation using only a small fraction of the beam power with S/N ratio of 40 dB and does not require chopping and could be employed in a heterodyne instrument.