Correlation approach to propagation of terahertz pulse in dielectrics for material characterization

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.