Fluidic channel waveguide coupler for nl-volume sensing applications

A waveguide coupler configuration enabling the investigation of streaming liquids at terahertz frequencies is presented. The device is based on two electromagnetically coupled hollow core dielectric waveguides. One waveguide is air-filled and is used for terahertz signal transmission while the second waveguide is filled with the sample liquid. Experimental data supported by numerical field simulations are presented for an air-, water- and isopropanol-filled waveguide in the 0.2-0.8 THz frequency range.