The Study Of Terahertz Spectrum System Based On Fourier Transform

Terahertz wave is the electromagnetic radiation with the frequency range of0.1THz to10THz（1THz=1012Hz,wavelength rang of30μm to3mm）. In order to measure terahertzspectrum, Fourier transform spectrum measurement method is used. Fourier transformterahertz spectrometer system is set up, which is based on Michelson interferometer lightpath. The system is simple, wide bandwidth, fast aquisition speed and has wide applicationprospect. The following results have been achieved in this thesis.Transiation stages control system and data acquisition system has been designed usingLabVIEW software. Control and acquisition LabVIEW program has been used in terehertzone-dimension, two-dimension tansmission imaging and knife-edge measuring terahertz spotsize experiment. This has obtained good experimental result, which comfirmed thecorrectness of the LabVIEW program. It has realized synchronization of optical pathdifference change and terahertz interference intensity data acquisition in terahertz spectrummeasurement. Experimental data has been processed using Origin software.Fourier transform terahertz spectrum system has been built using laboratory equipment,and measured the spectrum of light pump terahertz sources. Measuring result has accordedwith theoretical value. In addition, frequency component with frequency interval of0.15THzhas been achieved, which is resulted from energy level transition of methanol molecules, notFourier transform terahertz spectrum system. It has been analysed that the relationship ofterahertz spectrum and these parameters of plane mirror’s displacement, movement velocity,sampling rate, pump light wavelength. Therefore, Fourier transform terahertz spectrumsystem can accurately measure terahertz spectrum and has high spectral resolution.