应用太赫兹时域光谱(THz-TDS)技术对红薯淀粉中的添加剂明矾进行了实验研究, 获得了红薯淀粉和明矾的太赫兹时域光谱和频域光谱, 通过计算得到二者的吸收系数谱和折射率谱, 吸收系数谱显示明矾在太赫兹波段有明显的特征吸收峰, 可以用THz-TDS技术对淀粉中的明矾进行特征识别。 实验获得了红薯淀粉中掺杂不同百分比(质量分数)明矾的太赫兹时域光谱, 计算得到吸收系数谱和折射率谱, 发现随着明矾含量的增加吸收峰的幅度下降, 折射率逐渐下降, 说明THz-TDS技术可以用于淀粉中明矾的定性识别和定量检测。

The Terahertz spectra of sweet potato starch, potassium alum and their compounds are measured in 0.3~2.0 THz using Terahertz time - domain spectroscopy ( THz-TDS) system. The refractive index and absorption coefficient spectrum are calculated. Experimental results show that potassium alum has distinct absorption features in the THz region, which can be used as fingerprint for the material identification. in addition, The Terahertz spectra of sweet potato starch doped with different percentages potassium alum are measured. The refractive index and absorption coefficient spectrum which are calculated indicate that the higher proportion of Potassium alum is, the larger the absorption coefficient in the compounds is. So is the refractive index. The results indicate that THz-TDS can be used to qualitative and quantitative detection ofpotassium alum in sweet potato starch.