Propagation characteristics of terahertz wave through a single slit

摘要

In the terahertz (THz) spectroscopic system, the research of propagation characteristics of terahertz electromagnetic field is very important. Using a single slit which width is close to the central wavelength of terahertz pulse, we investigate the spectral distribution of terahertz beam at the location of samples. We obtain the following results by analyzing the experimental data. Firstly, the size of THz beam is different for the THz wave of the different frequency. The width of THz beam is small for the high frequency of THz radiation. At the same frequency, THz beam becomes wider for the narrower slit, that is, THz wave show the obvious diffraction phenomenon. Secondly, the frequency spectra distribution is different at the different position of THz beam. The peak position of frequency spectra appears red shift with the increasing of the distance away from the center of terahertz beam. These results provide an important reference for the further terahertz experiments of spectroscopy and imaging.