Correlation Approach to Propagation of Terahertz Pulse in Dielectrics for Material Characterization

Abstract

With Maxwell's wave equation and an auxiliary equation, we devise a novel approach to simulate terahertz (THz) pulse propagation in a typical THz time-domain spectrometer for material diagnostics. This is based on a correlation analysis of experimentally measured THz wavefrom propagated through the sample and that of a simulated one with material properties as adjustable parameters. The Lorentz model for dielectrics is assumed. Using fused quartz as an example, we find this approach can yield reliable static relative permittivity and optical constants beyond the bandwidth of a THz pulse.

Equivalent source of reflector in finite‐different time‐domain for rapid analysis of corner scattering in terahertz computed tomography imaging

“…According to the model in Figure 3B, four samples were designed to analyze the effect of different permittivity on the corner scattering properties. The material composition of the samples is shown in Table 1, where the permittivities of polyimide, fused silica, and aluminum oxide (Al 2 O 3 ) are 3.43, 15 3.81, 16 and 9.32, 17 respectively. Since the materials of the three areas of sample A are the same, the corner structure of sample A disappears and sample A is smooth.…”