Double-beam CW THz system with photonic phase modulator for sub-THz glucose hydration sensing

We present a double-beam dielectric spectroscopic system using an integrated photonic phase modulator for glucose hydration sensing from 0.25 to 1.0 THz. Compact phase modulators with a photonic circuit and a double-beam scheme using a broadband beam splitter enable us to improve signal stability in sub-THz generation and detection. Using the system, we carried out fast vector measurement on glucose solutions with effective signal stabilization. By incorporating a simple calibration procedure for the extraction of dielectric properties, the Fabry-Perot effect in liquid cell window was mitigated. The system demonstrated accurate detection of glucose dielectric spectra for hydration analysis of glucose-water interaction in sub-THz region.