火焰碳黑是碳氢燃料不完全燃烧的重要固体产物,对于一些污染物的生成具有重要影响,其光学特性是光学燃烧诊断的基础。利用太赫兹时域光谱技术研究了0.2～1.6 THz火焰碳黑的光学特性,通过傅里叶变换得到了碳黑的频域光谱,利用定点迭代法获得了太赫兹波段火焰碳黑的复折射率,把太赫兹波段的复折射率与热辐射波段的复折射率进行了比较,此外还对比了两种光学参数提取方法所得到的结果,结果表明,碳黑在太赫兹波段的吸收性较强,其折射率在太赫兹波段与在热辐射波段的差别不是很大,而吸收率在热辐射波段变化更大一些,两种参数提取方法得到的复折射率差别不是很大,研究结果可为太赫兹波技术应用于光学燃烧诊断提供基础性数据,扩展了光学燃烧诊断应用的范围。

Flame soot is an import product as a result of incomplete combustion of hydrocarbon fuels, and has important effect on the generation of some pollutant. The optical properties of the soot are the base for the optical combustion diagnostics. Terahertz time-domain spectroscopy technique was used to study the optical properties of the soot within 0.2－1.6 THz and the frequencydomain spectra were obtained through Fourier transform. The complex refractive index of the soot was deduced by the fixed-point iteration. The comparison of the complex refractive index between terahertz spectra domain and thermal radiation spectra domain was conducted and two methods of extracting the parameters were also compared. The results indicated that the soot has strong absorption in the studied spectra and the difference in the refractive index between the two spectra domains was not obvious, but the absorptive index variation in the thermal radiation spectra domain was larger. The difference between the two parameter extraction methods was not significant. The deduced results can provide the optical data of soot for the application of terahertz time-domain spectroscopy technique to the optical combustion diagnostics, and extend the optical combustion diagnostics application area.