Light scattering effect of powder in terahertz subwavelength band

Light scattering effect can be commonly occurred in the terahertz transmitting spectra of various powders (particle sizes are average less than 50μm), include pure materials and mixtures. Light scattering of various materials distort absorption spectra. We demonstrate the effect using mixture of two kinds of powders with different refractive index. According to the Mie theory, we explain the reason of light scattering effect in subwavelength domain, relying on refractive index between the powders and their surrounding medium. Furthermore, we show a wavelet method which can extracts terahertz spectral information without considering scattering effect.

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