  A Bragg waveguide-based resonant fluidic sensor operating in THz band is
studied. A fused deposition modeling 3D printing technique is employed to
fabricate the sensor where the liquid analyte is flowing in the microfluidic
channel integrated into the waveguide cladding. The analyte refractive
index-dependent resonant defect state supported by the fluidic channel is
probed by tracking the resulting absorption dip and phase change of the
core-guided mode on waveguide transmission spectra. The proposed fluidic sensor
can open new opportunities in applied chemical and biological sensing as it
offers a non-contact measurement technique for monitoring refractive index
changes in flowing liquids.
