Far-infrared broadband measurements with Hilbert spectroscopy

A principal possibility of broadband far-infrared (FIR) spectral measurements with Hilbert- transform technique, based on ac Josephson effect, has been experimentally studied. High-pressure 200 W mercury arc lamp was used as a source of FIR broadband radiation. The grain-boundary YBaCuO thin-film Josephson junctions (JJ) with the normalstate resistance R-n = 1-3 Omega and the IcRn-product up to 1 mV were used in the experiments. Broadband spectra with different FIR mesh-type filters have been measured by this technique. First results on the detection of gas absorption spectra in FIR range with Hilbert spectroscopy (HS) were obtained. Several lines of CO absorption spectrum in the range from 300 up to 1000 GHz have been resolved, when broadband blackbody radiation passed through a gas cell. (C) 2002 Elsevier Science B.V. All rights reserved.