爆炸性物质太赫兹时间分辨光谱测量

利用自由空间电光取样方法，研究了四种炸药在太赫兹(THz)频段的光学特性。通过太赫兹时间分辨光谱测量，作者得到了四种炸药DNT(2,4-二硝基甲苯)、钝化的RDX(黑索今)、HMX(奥克托金)和TNT(2,4,6-三硝基甲苯)的透射光谱，进而计算得出它们在0.2～2.5 THz频段的吸收系数和折射率。作者发现，2,4-DNT在1.08 THz，HMX在1.82 THz存在显著的吸收尖峰，RDX在此频段存在多个吸收峰，TNT的吸收谱线相对其他三种样品比较平缓，这种共振吸收一般认为是由分子间相互作用或声子共振模式引起的。四种炸药对太赫兹波独特的吸收性质说明，太赫兹时间分辨光谱测量技术在炸药特征识别及安全检测领域具有潜在应用价值。作者对致癌物质偶氮苯进行了太赫兹光谱研究，发现了国产偶氮苯和进口偶氮苯在太赫兹波段均存在特征吸收峰，可用于物质鉴别。

Time-Resolved Terahertz Spectroscopy of Explosives

The authors present a time-resolved measurement in terahertz(THz) frequency region by means of the free-space electro-optic sampling(FSEOS).The transmission spectra and complex refractive index of four kinds of explosives were obtained.The authors found that DNT,RDX,HMX and TNT all have absorption peaks within the frequency range of 0.2 and 2.5 THz.It can be seen that DNT and HMX have obvious absorption peaks at 1.08 and 1.82 THz respectively.The authors can use the terahertz spectra as the fingerprint of the detected materials.Therefore,time-resolved terahertz spectroscopy can be applied to detect and identify explosives.The authors also detected a kind of carcinogen named azobenzene.The authors found that azobenzene bought both in China or from American all have the absorption peaks in the frequency range between 0.2 and 2.5 THz.