Propagation of terahertz radiation through random structures: An alternative theoretical approach and experimental validation

A model describing the propagation of terahertz frequency radiation through inhomogeneous materials is proposed. In such materials (e.g., powders or clothing), the size of the scattering centers, their separation, and the wavelength of the radiation are all commensurate. A phase distribution function is used to model the optical properties of a randomly structured transmitting layer. The predictions of the model are compared with exact (Mie) theory for isolated spherical scatterers and with previously published experimental data. Measurements of the transmission of terahertz radiation through a variety of samples in order to validate the present model are also reported. These include arrays of cylinders, textiles, powders, and glass balls. Overall, satisfactory agreement between the experimental data and theoretical predictions is obtained.