Terahertz spectroscopy is a promising tool for analyzing the picosecond dynamics of biomolecules, which is influenced by surrounding water molecules. However, water causes extreme losses to terahertz signals, preventing sensitive measurements at this frequency range. Here, we present sensitive on-chip terahertz spectroscopy of highly lossy aqueous solutions using a vector network analyzer, contact probes, and a coplanar waveguide with a 0.1-mm-wide microfluidic channel. The complex permittivities of various deionized water/isopropyl alcohol concentration are extracted from a known reference measurement across the frequency range 750–1100 GHz and agrees well with literature data. The results prove the presented method as a high-sensitive approach for on-chip terahertz spectroscopy of high-loss liquids, capable of resolving the permittivity of water.

中文翻译：

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750 GHz 至 1100 GHz 之间高损耗液体的片上表征

太赫兹光谱是一种很有前途的工具，可用于分析受周围水分子影响的生物分子的皮秒动力学。然而，水会导致太赫兹信号的极端损失，从而阻止在该频率范围内进行敏感测量。在这里，我们使用矢量网络分析仪、接触探针和具有 0.1 毫米宽微流体通道的共面波导，展示了高损耗水溶液的敏感片上太赫兹光谱。各种去离子水/异丙醇浓度的复介电常数是从 750–1100 GHz 频率范围内的已知参考测量中提取的，与文献数据非常吻合。结果证明所提出的方法是一种用于高损耗液体的片上太赫兹光谱的高灵敏度方法，能够解析水的介电常数。