[Analytical Chemistry] On-chip Terahertz-Frequency Measurements of Liquids
Terahertz-frequency-range measurements can offer potential insight into the picosecond dynamics, and therefore function, of many chemical systems. There is a need to develop technologies capable of performing such measurements in aqueous and polar environments, particularly when it is necessary to maintain the full functionality of biological samples. In this study, we present a proof-of-concept technology comprising an on-chip planar Goubau line, integrated with a microfluidic channel, which is capable of low-loss, terahertz-frequency-range spectroscopic measurements of liquids. We also introduce a mathematical model that accounts for changes in the electric field distribution around the waveguide, allowing accurate, frequency-dependent liquid parameters to be extracted. We demonstrate the sensitivity of this technique by measuring a homologous alcohol series across the 0.1-0.8 THz frequency range.
Matthew Swithenbank, Andrew David Burnett, Christopher Russell, Lianhe H. Li, Alexander Giles Davies, Edmund H. Linfield, John E. Cunningham, and Christopher David Wood Anal. Chem., Just Accepted Manuscript DOI: 10.1021/acs.analchem.7b01235 Publication Date (Web): July 6, 2017 Copyright © 2017 American Chemical Society