太赫兹电磁波低通滤波器与中药材指纹数据提取∗

摘要

太赫兹时域光谱技术可以为中药材鉴别和研究提供新方法。视每种中药材标准样品为一个太赫兹电磁波低通滤波器，用三参数二阶微分方程或频域系统函数H (f )描述滤波器的特性。利用中药材的透射太赫兹电磁波电场强度时域波形采样数据和频域幅频数据，可以计算出中药滤波器的阻尼系数α、固有频率β、放大系数γ。数据分析发现，所用的5种中药材都有惟一确定的滤波器参数，若用中药材的二阶阻尼振子的三个参数作为中药材的指纹数据，可以有效地区分不同种类的中药材。%Terahertz time-domain spectroscopy provides a new method of identifying and studying Chinese herbal medicines. We utilize a second-order terahertz filter to describe the samples of Chinese herbal medicines, and the behaviors of terahertz filter are characterized by a second-order differential equations with three parameters {α,β,γ} or the corre-sponding frequency domain system function H (f ). The results of data analysis show that five kinds of Chinese herbal medicines which are used in the experiments have unique filter parameters. Thus, if these filter parameters are used as the fingerprint data of Chinese herbal medicines, we can effectively determine the types and origins of Chinese herbal medicines.