A Method for Measuring the Complex Refractive Index of Low-Volume Materials Using Integrated Terahertz Time-Domain Transmissometry

This study presents the development of an on-chip terahertz characterization process for low-volume or thin-film materials. A time-domain method based on the transmission of picosecond electrical pulses through the material to be characterized is proposed to determine the complex refractive index of materials up to hundreds of gigahertz. We demonstrate the capability of this method by determining the complex refractive index of a 15 nL droplet of glycerol over the 50–550 GHz frequency range.