Photonic Bandgap Bragg Waveguide-based Terahertz Microfluidic Sensor

A 3D printed photonic bandgap Bragg waveguide-based resonant fluidic sensor operating in the THz spectral range is theoretical analyzed and experimental studied. The liquid analytes injected into a microfluidic channel inside the reflector region result in anticrossing of the dispersion relation between the core-guided mode and the defect state. By tracking the spectral positions of the induced absorption dips and phase changes on the transmission spectra, the fluidic sensor exhibits a sensitivity of 110 GHz/RIU and a resolution of 0.0045 RIU. The sensor provides a non-contact measurement method for real-time monitoring of the refractive index change of liquid flow in practical applications.