Research on THz On-Chip System Based on Asynchronous Optical Sampling

Currently, terahertz (THz) technology has various applications in the sensing field, which can rely on the resonance absorption effect of biology to detect the fingerprint spectrum of substances and sense their concentration. In this study, we developed a THz on-chip system that integrates THz generation, transmission, and detection using self-made LT-GaAs epitaxial wafers. An asynchronous optical sampling system and a THz on-chip system were used to detect the concentration of nicotinamide, pyrazinamide and riboflavin solutions. The obtained THz signals show good signal-to-noise ratio. Meanwhile, the solid samples of each sample are verified by traditional THz-TDS system, and the results show that the on-chip system has good accuracy. The efficiency of the system in solution concentration sensing and sample identification was demonstrated. The system has the advantage of rapid detection and is suitable for transient measurement of organic solutions or bioactive substances. In addition, we use the simulation software CST studio suite to simulate the experimental process and explain the experimental principle. The simulation results are in good self-agreement with the experimental results, which proves the feasibility of the whole experimental system.