太赫兹波能与极性液体的氢键发生强烈的共振吸收作用, 分子极性越大, 吸收作用越强。基于此特性, 在 0.2～1.0 THz波段利用太赫兹时域光谱技术对甲醇、乙醇、正丙醇、正丁醇四种一元醇液体的极性进行检测研究。根据测量得到的四种液体太赫兹波谱数据, 得出了液体的极性与其太赫兹波谱的关系式, 再利用此关系式求得四种液体的计算值。通过对四种液体极性的标准值和计算值比对, 验证了所得液体极性求取公式的有效性。研究结果表明, 四种不同液体的时域光谱因分子的极性差异有显著的不同, 所用的液体极性测量方法能够对液体的极性进行快速有效的检测与鉴别, 可为其他液体极性的检测提供参考。

Terahertz (THz) wave has strong resonance absorption with the hydrogen bond of polar substances. The bigger the molecular polarity, the stronger the absorption. Based on this characteristic, monohydric alcohol liquids from methanol to 1-butanolwere have been detected by terahertz time-domain spectroscopy (THz-TDS) within the spectral range of 0.2-1.0 THz. The relationship between the polarity of monohydric alcohol and their terahertz spectra are analyzed, which proves that the terahertz spectroscopy of monohydric alcohol molecules is mainly determined by the polarity, which can be quantitatively calculated. These results conclude that terahertz spectroscopy can realize the effective and fast identification of the polarity of chemical solution, which can provide a reference for liquid polarity detection.