Journal ArticleDOI
Atmospheric absorption of terahertz radiation and water vapor continuum effects
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TLDR
In this article, the water vapor continuum absorption spectrum was investigated using Fourier transform spectroscopy (FTS) and the absorption coefficient as a function of frequency was determined and compared with theoretical predictions and available water vapor absorption data.Abstract:
The water vapor continuum absorption spectrum was investigated using Fourier Transform Spectroscopy. The transmission of broadband terahertz radiation from 0.300 to 1.500 THz was recorded for multiple path lengths and relative humidity levels. The absorption coefficient as a function of frequency was determined and compared with theoretical predictions and available water vapor absorption data. The prediction code is able to separately model the different parts of atmospheric absorption for a range of experimental conditions. A variety of conditions were accurately modeled using this code including both self and foreign gas broadening for low and high water vapor pressures for many different measurement techniques. The intensity and location of the observed absorption lines were also in good agreement with spectral databases. However, there was a discrepancy between the resonant line spectrum simulation and the observed absorption spectrum in the atmospheric transmission windows caused by the continuum absorption. A small discrepancy remained even after using the best available data from the literature to account for the continuum absorption. From the experimental and resonant line simulation spectra the air-broadening continuum parameter was calculated and compared with values available in the literature.read more
Citations
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Journal ArticleDOI
Determination of the water vapor continuum absorption by THz-TDS and Molecular Response Theory.
TL;DR: An accurate continuum absorption is obtained within four THz absorption windows, that agrees well with the empirical theory and is significantly smaller than that obtained using the van Vleck-Weisskopf lineshape with a 750 GHz cut-off.
Journal ArticleDOI
Nanoscale Surface Roughness Effects on THz Vacuum Electron Device Performance
Diana Gamzina,Hanyan Li,Logan Himes,Robert Barchfeld,Branko Popovic,Pan Pan,Rosa Letizia,Mauro Mineo,Jinjun Feng,Claudio Paoloni,Neville C. Luhmann +10 more
TL;DR: In this article, the surface roughness of metal waveguides has been investigated at the nanoscale using microfabrication techniques, and two significant examples are considered: a 0.346-THz backward wave tube oscillator and an 0.263-thz traveling wave tube.
Book ChapterDOI
Waves and Fields
TL;DR: In this article, the authors considered a homogeneous lossless material at far distance from the source and in a limited angular range such that the field is regarded as a function of distance r only.
Journal ArticleDOI
Terahertz communications at various atmospheric altitudes
TL;DR: Numerical results show that as the altitude increases, the concentration of the water vapor molecules decreases, enabling the communication over the THz-band to be more feasible as compared to the sea-level communication.
Journal ArticleDOI
910-m propagation of THz ps pulses through the Atmosphere.
TL;DR: A new procedure involving the measurement of phase in the frequency domain is introduced and achieves comparable results for the calculated time shifts, compared to the previous direct measurements of time shifts.
References
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The HITRAN 2008 molecular spectroscopic database
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Infrared Study of Adsorbed Molecules on Metal Surfaces by Reflection Techniques
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The HITRAN 2008 molecular spectroscopic database
Laurence S. Rothman,Iouli E. Gordon,Yurii L. Babikov,A. Barbe,D. Chris Benner,Peter F. Bernath,Manfred Birk,Luca Bizzocchi,Vincent Boudon,Linda R. Brown,Alain Campargue,Kelly Chance,Edward A. Cohen,L. H. Coudert,V. M. Devi,Brian J. Drouin,André Fayt,Jean-Marie Flaud,Robert R. Gamache,Jeremy J. Harrison,Jean-Michel Hartmann,Christian Hill,Joseph T. Hodges,D. Jacquemart,Antoine Jolly,Julien Lamouroux,R. J. Le Roy,Gang Li,David A. Long,O.M. Lyulin,C.J. Mackie,Steven T. Massie,Semen Mikhailenko,Holger S. P. Müller,Olga V. Naumenko,Andrei Nikitin,Johannes Orphal,V.I. Perevalov,Agnes Perrin,E. R. Polovtseva,Charlotte Richard,Mary Ann H. Smith,Evgeniya Starikova,Keeyoon Sung,S.A. Tashkun,Jonathan Tennyson,Geoff Toon,Vl.G. Tyuterev,G. Wagner +48 more