| In this thesis, the Finite-Difference-Time-Domain (FDTD) method is applied to time-resolved-terahertz-spectroscopy (TRTS) experiments in superconductors and semiconductors. In a TRTS experiment, a pump pulse (400nm/800nm) is used to excite the sample, after which a terahertz (THz) pulse arrives to probe the sample at different delay times. The transient changes in the optical properties of the excited medium are obtained as a function of the delay time between the pump and THz probe pulses by analyzing the transmitted THz probe pulses.; The FDTD method can effectively reproduce and interpret the phenomena occurring in TRTS experiments by simulating the propagation of THz probe pulses through the excited medium. By using this method, some proposed theoretical models can be verified and many optical parameters of the medium can be obtained by fitting the simulated output THz probe pulses to the experimental results. |
