We present experimental results as well as modelling concerning terahertz (THz) wave scattering by powder materials with grain size of the order of the wavelength. The studied material is a mixture of high density polyethylene and fructose powders, whose grain size is varied from a sample to another one while the volume concentration is kept constant. Experimental data are recorded with a THz time-domain spectroscopy set up. The scattering contribution to the total propagation loss in such powders shows a resonant behaviour for grain size roughly equal to the THz wavelength, for which it reaches 80%–90% of the total loss. Modelling using Mie theory allows us to well describe the absorption and scattering phenomena.
Abstract-Terahertz spectroscopy brings precious complementary information in life science by probing directly low energy bindings inside matter. This property has been demonstrated on dehydrated substances, and interesting results are obtained on liquid solutions. The next step is the characterization of living cells.We have successfully integrated THz passive circuits inside Biological MicroElectroMechanical Systems (BioMEMS). They are based on metallic wires called Planar Goubau Line (PGL). We demonstrate that high THz measurement sensitivity can be reached with new design based on spirals. But we show that the principal interest of this design is its high spatial resolution below the wavelength size compatible with living cell investigation.
The structure of most of fabrics is an almost periodic network of interlaced yarns or threads, whose periodicity is of the order of the terahertz wavelength. We report here on the diffraction of terahertz electromagnetic waves by the yarn network in common cloths. In the case of linen, this effect could lead to overestimating (by a factor as large as 3) the absorption when determined from the classical terahertz time-domain experiment. Our results are confirmed by a HFSS numerical simulation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.