云冈石窟石质、降尘样品的太赫兹光谱分析

Research on Terahertz Spectrum of the YunGang Grotto Samples

利用太赫兹时域光谱系统,分析了由云冈石窟所采集的石柱、降尘和新鲜岩石3种样品在THz波段的光谱特征。通过比较分析得出,3种样品在整个波段,均无明显的吸收峰,低频区吸收都很弱,高频区吸收系数以接近指数函数趋势增长,特别是降尘的吸收最大,新鲜岩石的次之,石柱的吸收最弱。在整个波段,石柱的折射率很稳定,基本不发生变化,其余两个样品的折射率则发生波动。

In this paper,the terahertz time domain spectroscopy technology is used to analyse the terahertz spectral characteristics of the World Cultural Heritages of Yungang Grottoes samples.The three samples are column,dust and fresh rock separately.It is found that the three samples have not distinct absorption peak in the whole THz wave band.Experimental results also indicate that all of the samples have weak absorption in low frequency region,but the absorption coefficient increased quickly by exponential function as the frequency increasing.This character is more obvious especially for the absorption spectrum of the dust,followed by fresh rock;column＇s absorption is the weakest.In the whole THz wave band,the refraction coefficient of column is very stable,while the other two samples are fluctuated.