Development of planar Goubau line – microfluidic integrated devices for THz spectroscopy of liquid analytes

We demonstrate the integration of planar Goubau lines with microfluidic systems for the measurement of liquid samples including water and isopropanol. Picosecond pulses are generated and detected by the inclusion of low-temperature-grown GaAs based photoconductive switches which transmit picosecond pulses along the transmission line. A change in the propagation velocity of pulses is detected and is used to estimate the permittivity of each liquid.