Josephson Spectroscopy for Identification of Liquids

One of future public security techniques will be related with non-invasive, fast and reliable detection of liquids. To distinguish between liquids under concern, we have suggested a concept using our Hilbert spectroscopy, based on high-Tc Josephson junctions. This spectroscopy is the only technique, which covers a frequency range of main dispersions of liquids from a few GHz to a few THz. Several demonstration setups of liquid identifiers, consisting of Hilbert spectrometers integrated on Stirling coolers and polychromatic radiation sources, have been developed. A critical consideration of the main sources of fluctuations in these measurements was carried out and a signal accuracy of around 0.3% has been reached with a total measurement time of a few seconds. Identification of samples of benign and threat liquids was demonstrated.