太赫兹(THz)波检测是一种新型有效的相干检测方法,它可以同时获得被检测物质的振幅和相位信息.利用太赫兹时域光谱技术(THz-TDS)对几种常见水进行了测谱分析;采取迭代的方法,消除了吸收近似带来的误差,完善了透射式太赫兹时域光谱技术中传统的数据处理方法;通过比较不同的滤波器,确定了Symlets9 小波滤波为最优的滤波方式;拟合得到了折射率和吸收系数随频率指数变化的规律,其相关系数的平方达到0.9 以上.结果表明,不同水的折射率和吸收系数变化曲线的参数值的差异和拟合相关性的不同,可以作为区分水质好坏的依据.

Terahertz (THz) detection is a novel and very effective coherent detection method,and both abundant amplitude information and ample phase information of materials which need to be detected and consequently contrast can be achieved.The THz spectral properties of several kinds of water are investigated based on the terahertz time domain spectroscopy (THZ-TDS) system.A sort of iterative approach is given,in order to avoid the result error caused by weak absorption approximation,which improves the traditional methods of data processing of transmission spectroscopy of terahertz time-domain.Compared with different filters,Symlets9 wavelet filter is considered to be optimal filter.The exponential change laws of refractive index and absorption coefficient with frequency are gotten with square of correlation coefficient up to 0.9 upwards.The results indicate that both square of correlation coefficient and fitting curve parameters of different kinds of water are different,which can be defined as the criteria to distinguish water quality.